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19-2536; Rev 0; 7/02
15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
General Description
The MAX3060E/MAX3061E/MAX3062E high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature failsafe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This means that the receiver output is a logic high if all transmitters on a terminated bus are disabled (high impedance). These devices also feature hot-swap circuitry that eliminates data glitches during hot insertion. The MAX3060E features slew-rate-limited drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 115kbps. The MAX3061E, also slewrate limited, transmits up to 500kbps. The MAX3062E driver is not slew-rate limited, allowing transmit speeds up to 20Mbps. All transmitter outputs are protected to 15kV using the Human Body Model. These transceivers typically draw 910A of supply current when unloaded, or 790A when fully loaded with the drivers disabled. All devices have a 1/8-unit-load receiver input impedance that allows up to 256 transceivers on the bus. These devices are intended for half-duplex communication.
Features
o True Fail-Safe Receiver While Maintaining EIA/TIA-485 Compatibility o Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission (MAX3060E and MAX3061E) o 1nA Low-Current Shutdown Mode o Hot-Swappable for Telecom Applications o ESD Protection: 15kV Human Body Model o Allow Up to 256 Transceivers on the Bus o Space-Saving 8-Pin SOT23 Package
MAX3060E/MAX3061E/MAX3062E
Ordering Information
PART MAX3060EEKA-T MAX3061EEKA-T MAX3062EEKA-T TEMP RANGE -40C to +85C -40C to +85C -40C to +85C PINPACKAGE 8 SOT23-8 8 SOT23-8 8 SOT23-8 TOP MARK AAKI AAKJ AAKK
Applications
RS-422/RS-485 Communications Level Translators Transceivers for EMI-Sensitive Applications Industrial-Control Local-Area Networks
PART MAX3060E MAX3061E MAX3062E DATA RATE (Mbps) 0.115 0.5 20
Selector Guide
SLEWRATE LIMITED Yes Yes No TRANSCEIVERS ON BUS 256 256 256
Typical Operating Circuit/Pin Configuration
+5V
TOP VIEW
RO 1 R 8 VCC 7B Rt 6 A 5 GND
0.1F
MAX3060E MAX3061E MAX3062E
B Rt A R
DE D DI
RE 2 DE 3 DI 4 D
RO
RE
________________________________________________________________ Maxim Integrated Products
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
ABSOLUTE MAXIMUM RATINGS
All Voltages with Respect to GND Supply Voltage (VCC) ............................................................+7V Input Voltage (RE, DE, DI)..........................-0.3V to (VCC + 0.3V) Driver Output/Receiver Input Voltage (A, B) .......-7.5V to +12.5V Receiver Output Voltage (RO)....................-0.3V to (VCC + 0.3V) Continuous Power Dissipation (TA = +70C) 8-Pin SOT23 (derate 8.9mW/C above +70C)............714mW Operating Temperature Range MAX306_EE_ _ ................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Junction Temperature ......................................................+150C Lead Temperature (soldering, 10s) .................................+300C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Notes 1, 2)
PARAMETER DRIVER Differential Driver Output (No Load) Differential Driver Output Change in Magnitude of Differential Output Voltage Driver Common-Mode Output Voltage Change in Magnitude of Common-Mode Voltage Input High Voltage Input Low Voltage DI Input Hysteresis Input Current Hot-Swap Driver Input Current Input Current (A and B) Driver Short-Circuit Output Current ESD Protection for A, B VOD1 VOD2 VOD VOC VOC VIH VIL VHYS IIN1 IHOTSWAP IIN2 VOD1 DE, DI, RE DE, RE (Note 4) DE = GND, VCC = GND or 5.25V VIN = +12V VIN = -7V -100 15 7 7 15 kV 250 VCC = 5V Figure 1, R = 50 (RS-422) Figure 1, R = 27 (RS-485) Figure 1, R = 50 or R = 27 (Note 3) Figure 1, R = 50 or R = 27 Figure 1, R = 50 or R = 27 (Note 3) DE, DI, RE DE, DI, RE 100 1 200 125 2.0 0.8 2.0 1.5 0.2 3 0.2 5 V V V V V V V mV A A A mA SYMBOL CONDITIONS MIN TYP MAX UNITS
-7V VOUT +12V, TA = +25C (Note 5) IEC 1000-4-2 Air-Gap Discharge IEC 1000-4-2 Contact Discharge Human Body Model
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
DC ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Notes 1, 2)
PARAMETER RECEIVER Receiver Differential Threshold Voltage Receiver Input Hysteresis Receiver Output High Voltage Receiver Output Low Voltage Three-State Output Current at Receiver Receiver Input Resistance Receiver Output Short-Circuit Current SUPPLY CURRENT Supply Current Supply Current in Shutdown Mode ICC ISHDN No load, DI = GND or VCC DE = GND, RE = VCC DE = RE = GND DE = RE = VCC 790 910 0.001 1400 1500 1 A A VTH VTH VOH VOL IOZR RIN IOSR IO = -4mA, VID = -50mV IO = 4mA, VID = -200mV 0V VO VCC -7V VCM +12V 0V VRO VCC 96 8 80 0.01 VCC - 1.5 0.4 1 -7V VCM +12V -200 -125 25 -50 mV mV V V A k mA SYMBOL CONDITIONS MIN TYP MAX UNITS
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
SWITCHING CHARACTERISTICS--MAX3060E
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Notes 1, 2)
PARAMETER Driver Input to Output Driver Output Skew (tDPLH - tDPHL) Driver Rise or Fall Time Maximum Data Rate Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Input to Output Differential Receiver Skew (tRPLH - tRPHL) Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Time to Shutdown Driver Enable from Shutdown to Output High Driver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low SYMBOL tDPLH, tDPHL tDSKEW tDR, tDF fMAX tDZH tDZL tDLZ tDHZ tRPLH, tRPHL tRSKD tRZL tRZH tRLZ tRHZ tSHDN Figures 4 and 6, CL = 100pF, S2 closed Figures 4 and 6, CL = 100pF, S1 closed Figures 4 and 6, CL = 15pF, S1 closed Figures 4 and 6, CL = 15pF, S2 closed Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed (Note 6) 50 180 -10 CONDITIONS Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF MIN 1.0 -200 1.3 115 0.6 0.5 60 85 47 -3 1.5 1.5 200 200 80 +10 50 50 50 50 600 2 2 1.5 1.5 TYP 1.7 -7 1.85 MAX 2.4 +200 2.5 UNITS s ns s kbps s s ns ns ns ns ns ns ns ns ns s s s s
tDZH(SHDN) Figures 4 and 6, CL = 100pF, S2 closed tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
SWITCHING CHARACTERISTICS--MAX3061E
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Notes 1, 2)
PARAMETER Driver Input to Output Driver Output Skew (tDPLH - tDPHL) Driver Rise or Fall Time Maximum Data Rate Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Input to Output Differential Receiver Skew (tRPLH - tRPHL) Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Time to Shutdown Driver Enable from Shutdown to Output High Driver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low SYMBOL tDPLH, tDPHL tDSKEW tDR, tDF fMAX tDZH tDZL tDLZ tDHZ tRPLH, tRPHL tRSKD tRZL tRZH tRLZ tRHZ tSHDN tDZH(SHDN Figures 4 and 6, CL = 100pF, S2 closed Figures 4 and 6, CL = 100pF, S1 closed Figures 4 and 6, CL = 15pF, S1 closed Figures 4 and 6, CL = 15pF, S2 closed Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed (Note 6) Figures 4 and 6, CL = 100pF, S2 closed 50 180 -10 CONDITIONS Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF MIN 250 -100 200 500 330 200 60 80 47 -3 1000 1000 200 200 80 +10 50 50 50 50 600 1.5 1.5 1.5 1.5 TYP 470 -4 530 MAX 800 +100 750 UNITS ns ns ns kbps ns ns ns ns ns ns ns ns ns ns ns s s s s
MAX3060E/MAX3061E/MAX3062E
tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
SWITCHING CHARACTERISTICS--MAX3062E
(VCC = +5V 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25C.) (Notes 1, 2)
PARAMETER Driver Input to Output Driver Output Skew (tDPLH - tDPHL) Driver Rise or Fall Time Maximum Data Rate Driver Enable to Output High Driver Enable to Output Low Driver Disable Time from Low Driver Disable Time from High Receiver Input to Output Differential Receiver Skew (tRPLH - tRPHL) Receiver Enable to Output Low Receiver Enable to Output High Receiver Disable Time from Low Receiver Disable Time from High Time to Shutdown Driver Enable from Shutdown to Output High Driver Enable from Shutdown to Output Low Receiver Enable from Shutdown to Output High Receiver Enable from Shutdown to Output Low SYMBOL tDPLH, tDPHL tDSKEW tDR, tDF fMAX tDZH tDZL tDLZ tDHZ tRPLH, tRPHL tRSKD tRZL tRZH tRLZ tRHZ tSHDN Figures 4 and 6, CL = 100pF, S2 closed Figures 4 and 6, CL = 100pF, S1 closed Figures 4 and 6, CL = 15pF, S1 closed Figures 4 and 6, CL = 15pF, S2 closed Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 7 and 9; | VID | 2.0V; rise and fall time of VID 4ns, CL = 15pF Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed Figures 2 and 8, CL = 15pF, S1 closed Figures 2 and 8, CL = 15pF, S2 closed (Note 6) 50 180 -10 CONDITIONS Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF Figures 3 and 5, RDIFF = 54, CDIFF = 50pF 20 250 250 100 100 45 -4 500 500 200 200 80 +10 50 50 50 50 600 100 100 1.5 1.5 -10 MIN TYP 20 +1 8 MAX 30 +10 15 UNITS ns ns ns Mbps ns ns ns ns ns ns ns ns ns ns ns ns ns s s
tDZH(SHDN) Figures 4 and 6, CL = 100pF, S2 closed tDZL(SHDN) Figures 4 and 6, CL = 100pF, S1 closed tRZH(SHDN) Figures 2 and 8, CL = 15pF, S2 closed tRZL(SHDN) Figures 2 and 8, CL = 15pF, S1 closed
Note 1: Overtemperature limits are guaranteed by design and are not production tested. Devices are tested at TA = +25C. Note 2: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device ground, unless otherwise noted. Note 3: VOD and VOC are the changes in VOD and VOC, respectively, when the DI input changes state. Note 4: This input current level is for the hot-swap enable (DE, RE) inputs and is present until the first transition only. After the first transition, the input reverts to a standard high-impedance CMOS input with input current IIN1. For the first 10s, the input current can be as high as 1mA. During this period the input is disabled. Note 5: Maximum current level applies to peak current just prior to foldback-current limiting; minimum current level applies during current limiting. Note 6: The device is put into shutdown by bringing RE high and DE low. If the enable inputs are in this state for less than 50ns, the device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteed to have entered shutdown.
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
A R VOD2 R B VOC S2 RECEIVER OUTPUT TEST POINT S1 1k 1k VCC
CL 15pF
Figure 1. Driver DC Test Load
Figure 2. Receiver Enable/Disable Timing Test Load
5V DE DI A VOD2 B RDIFF CDIFF OUTPUT UNDER TEST CL S2 500 S1 VCC
Figure 3. Driver Timing Test Circuit
Figure 4. Driver Enable/Disable Timing Test Load
5V DI 0 1.5V tDPLH tDPHL 1.5V DE
5V 1.5V 0 tDZL(SHDN), tDZL A, B VOL 2.3V OUTPUT NORMALLY LOW OUTPUT NORMALLY HIGH 2.3V 0 tDZH(SHDN), tDZH tDHZ VOH - 0.5V VOL + 0.5V tDLZ 1.5V
B A VDIFF = V (A) - V (B) 10% tDR 90% 90%
VDIFF
VO 0 -VO
A, B 10%
tDF tDSKEW = | tDPLH - tDPHL |
Figure 5. Driver Propagation Delays
Figure 6. Driver Enable and Disable Times
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
5V RE 0 RO VOH VOL A B 1.5V tRPHL INPUT RO 0 tRZH(SHDN), tRZH tRHZ 1.5V OUTPUT tRPLH OUTPUT NORMALLY HIGH VOH - 0.5V 1.5V VCC RO tRZL(SHDN), tRZL tRLZ VOL + 0.5V 1.5V 1.5V
1.5V OUTPUT NORMALLY LOW
1V -1V
Figure 7. Receiver Propagation Delays
Figure 8. Receiver Enable and Disable Times
B ATE VID A RR RECEIVER OUTPUT
Figure 9. Receiver Propagation Delay Test Circuit
Typical Operating Characteristics
(VCC = +5V, TA = +25C, unless otherwise noted.)
NO-LOAD SUPPLY CURRENT vs. TEMPERATURE
MAX3060E toc01
RECEIVER OUTPUT CURRENT vs. RECEIVER OUTPUT LOW VOLTAGE
MAX3060E toc02
RECEIVER OUTPUT CURRENT vs. RECEIVER OUTPUT HIGH VOLTAGE
18 16 OUTPUT CURRENT (mA) 14 12 10 8 6 4 2
MAX3060E toc03
950 DE = RE = VCC NO-LOAD SUPPLY CURRENT (A) 900 850 800 750 700 650 -40 -15 10 35 60 DE = RE = GND
60 50 OUTPUT CURRENT (mA) 40 30 20 10 0
20
0 0 1 2 3 4 5 0 1 2 3 4 5 OUTPUT LOW VOLTAGE (V) OUTPUT HIGH VOLTAGE (V)
85
TEMPERATURE (C)
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
MAX3060E/MAX3061E/MAX3062E MAX3060E/MAX3061E/MAX3062E
SHUTDOWN CURRENT vs. TEMPERATURE
MAX3060E toc04
RECEIVER OUTPUT LOW VOLTAGE vs. TEMPERATURE
MAX3060E toc05
RECEIVER OUTPUT HIGH VOLTAGE vs. TEMPERATURE
4.2 OUTPUT HIGH VOLTAGE (V) 4.0 3.8 3.6 3.4 IRO = -8mA
MAX3060E toc06
5.0 4.5 SHUTDOWN CURRENT (nA) 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 -40 -15 10 35 60
0.50 0.45 OUTPUT LOW VOLTAGE (V) 0.40 0.35 0.30 0.25 0.20 0.15 0.10 IRO = 8mA
3.2 -40 -15 10 35 60 85 -40 -15 10 35 60 85 TEMPERATURE (C) TEMPERATURE (C)
85
TEMPERATURE (C)
RECEIVER PROPAGATION DELAY (MAX3060E/MAX3061E) vs. TEMPERATURE
MAX3060E toc07
RECEIVER PROPAGATION DELAY (MAX3062E) vs. TEMPERATURE
MAX3060E toc08
DRIVER PROPAGATION DELAY (MAX3060E) vs. TEMPERATURE
1.78 PROPAGATION DEALY (s) 1.76 1.74 1.72 1.70 1.68 1.66 1.64 1.62 1.60 Rt = 54
MAX3060E toc09
70 65 PROPAGATION DEALY (ns) 60 55 50 45 40 35 30 25 20 -40 -15 10 35 60 CL = 15pF
70 65 PROPAGATION DEALY (ns) 60 55 50 45 40 35 30 25 20 CL = 15pF
1.80
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
DRIVER PROPAGATION DELAY (MAX3061E) vs. TEMPERATURE
MAX3060E toc10
DRIVER PROPAGATION DELAY (MAX3062E) vs. TEMPERATURE
MAX3060E toc11
DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs. TEMPERATURE
Rt = 54 3.2 OUTPUT VOLTAGE (V) 3.0 2.8 2.6 2.4 2.2 2.0
MAX3060E toc12
540 Rt = 54 520 PROPAGATION DELAY (ns) 500 480 460 440 420 400 -40 -15 10 35 60
30 Rt = 54 25 PROPAGATION DELAY (ns) 20 15 10 5 0
3.4
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (C)
TEMPERATURE (C)
TEMPERATURE (C)
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
Typical Operating Characteristics (continued)
(VCC = +5V, TA = +25C, unless otherwise noted.)
DRIVER OUTPUT CURRENT vs. DIFFERENTIAL OUTPUT VOLTAGE
MAX3060E toc13
DRIVER OUTPUT CURRENT vs. OUTPUT LOW VOLTAGE
MAX3060E toc14
DRIVER OUTPUT CURRENT vs. OUTPUT HIGH VOLTAGE
MAX3060E toc15
100
90 80 DRIVER OUTPUT CURRENT (mA) 70 60 50 40 30 20 10
120 DRIVER OUTPUT CURRENT (mA) 100 80 60 40 20
OUTPUT CURRENT (mA)
10
1
0.1
0.01 0 1 2 3 4 5 6 DIFFERENTIAL OUTPUT VOLTAGE (V)
0 0 2 4 6 8 10 12 OUTPUT LOW VOLTAGE (V)
0 -8 -6 -4 -2 0 2 4 6 OUTPUT HIGH VOLTAGE (V)
RECEIVER PROPAGATION DELAY (MAX3060E/MAX3061E)
MAX3060E toc16
RECEIVER PROPAGATION DELAY (MAX3062E)
MAX3060E toc17
DRIVER PROPAGATION DELAY (MAX3061E)
MAX3060E toc18
VA - VB 1V/div
VA - VB 1V/div
DI 5V/div
RO 5V/div
RO 5V/div VA - VB 2V/div
20ns/div
20ns/div
1s/div
DRIVER PROPAGATION DELAY (MAX3060E)
MAX3060E toc19
DRIVER PROPAGATION DELAY (MAX3061E)
MAX3060E toc20
DRIVER PROPAGATION DELAY (MAX3062E)
MAX3060E toc21
DI 5V/div DI 5V/div
VA - V B 2V/div 2s/div 10ns/div
VA - VB 2V/div 20ns/div
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
Pin Description
PIN 1 NAME RO FUNCTION Receiver Output. When RE is low and when A - B -50mV, RO is high; if A - B -200mV, RO is low. RO is high impedance when RE is high. Receiver Output Enable. Drive RE low to enable RO; RO is high impedance when RE is high. Drive RE high and DE low to enter low-power shutdown mode. RE is a hot-swap input and reverts to a standard CMOS input after the first low transition. Driver Output Enable. Drive DE high to enable driver outputs. Driver outputs are high impedance when DE is low. Drive RE high and DE low to enter low-power shutdown mode. DE is a hot-swap input and reverts to a standard CMOS input after the first high transition. Driver Input. With DE high, a low on DI forces the noninverting output low and the inverting output high. Similarly, a high on DI forces the noninverting output high and the inverting output low. Ground Noninverting Receiver Input and Noninverting Driver Output Inverting Receiver Input and Inverting Driver Output Positive Supply. Bypass with a 0.1F capacitor to GND.
MAX3060E/MAX3061E/MAX3062E MAX3060E/MAX3061E/MAX3062E
2
RE
3
DE
4 5 6 7 8
DI GND A B VCC
Detailed Description
The MAX3060E/MAX3061E/MAX3062E high-speed transceivers for RS-485/RS-422 communication contain one driver and one receiver. These devices feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted, or when they are connected to a terminated transmission line with all drivers disabled (see the Fail Safe section). All devices have a hot-swap input structure that prevents disturbances on the differential signal lines when a circuit board is plugged into a hot backplane (see the Hot-Swap Capability section). The MAX3060E features a reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 115kbps (see the Reduced EMI and Reflections section). The MAX3061E is also slew-rate limited, transmitting up to 500kbps. The MAX3062E driver is not slew-rate limited, allowing transmit speeds up to 20Mbps. The MAX3060E/MAX3061E/ MAX3062E are half-duplex transceivers. All of these parts operate from a single +5V supply. Drivers are output short-circuit current limited. Thermalshutdown circuitry protects drivers against excessive power dissipation. When activated, the thermal-shutdown circuitry places the driver outputs into a highimpedance state.
Receiver Input Filtering
The receivers of the MAX3060E and MAX3061E incorporate input filtering in addition to input hysteresis. This filtering enhances noise immunity with differential signals that have very slow rise and fall times. Receiver propagation delay increases by 2ns due to this filtering.
Fail-Safe
The MAX3060E family of devices guarantee a logic-high receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. This is done by setting the receiver threshold between -50mV and -200mV. If the differential receiver input voltage (A - B) is greater than or equal to -50mV, RO is logic high. If A - B is less than or equal to -200mV, RO is logic low. In the case of a terminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to 0V by the termination. In the case of an unterminated bus with all transmitters disabled, the receiver's differential input voltage is pulled to 0V by the receiver's input resistors. With the receiver thresholds of the MAX3060E family, this results in a logic high output with a 50mV minimum input noise margin. Unlike previous fail-safe devices, the -50mV to -200mV threshold complies with the 200mV EIA/TIA-485 standard.
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
Functional Tables
Table 1. Transmitter Functional Table
TRANSMITTING INPUTS RE X X 0 1 DE 1 1 0 0 DI 1 0 X X B 0 1 High-Z Shutdown* OUTPUTS A 1 0 High-Z RE 0 0 0 1 1 DE X X X 1 0
Table 2. Receiver Functional Table
RECEIVING INPUTS A-B -0.05V -0.2V Open/shorted X X OUTPUT RO 1 0 1 High-Z Shutdown
X = Don't care. *Shutdown mode, driver and receiver outputs are high impedance.
Hot-Swap Capability
Hot-Swap Input When circuit boards are inserted into a hot or powered backplane, differential disturbances to the data bus can lead to data errors. Upon initial circuit board insertion, the data communication processor undergoes its own powerup sequence. During this period, the processor's logicoutput drivers are high impedance and are unable to drive the DE and RE inputs of the MAX306_E to a defined logic level. Leakage currents up to 10A from the highimpedance state of the processor's logic drivers could cause standard CMOS enable inputs of a transceiver to drift to an incorrect logic level. Additionally, parasitic circuit board capacitance could cause coupling of VCC or GND to the enable inputs. Without the hot-swap capability, these factors could improperly enable the transceiver's driver or receiver. When VCC rises, an internal pulldown circuit holds DE low for at least 10s and until the current into DE exceeds 200A. After the initial positive transition, the pulldown circuit becomes transparent, resetting the hot-swap tolerable input. Hot-Swap Input Circuitry These devices' enable inputs feature hot-swap capability. At the input there are two NMOS devices, M1 and M2 (Figure 10). When VCC ramps from zero, an internal 10s timer turns on M2 and sets the SR latch, which also turns on M1. Transistors M2, a 300A current sink, and M1, a 30A current sink, pull DE to GND through an 8k resistor. M2 is designed to pull DE to the disabled state against an external parasitic capacitance up to 100pF that can drive DE high. After 10s, the timer deactivates M2 while M1 remains on, holding DE low against threestate leakages that can drive DE high. M1 remains on
12
until an external source overcomes the required input current. At this time, the SR latch resets and M1 turns off. When M1 turns off, DE reverts to a standard, highimpedance CMOS input. Whenever VCC drops below 1V, the hot-swap input is reset. For RE, there is a complementary circuit employing two PMOS devices pulling RE to VCC.
VCC 10s TIMER SR LATCH TIMER
8k DE 300A M2
DE (HOT SWAP)
30A M1
Figure 10. Simplified Structure of the Driver Enable Input (DE)
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15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
Hot-Swap Line Transient The circuit of Figure 11 shows a typical offset termination used to guarantee a greater than 200mV offset when a line is not driven (the 50pF represents the minimum parasitic capacitance that would exist in a typical application). During a hot-swap event when the driver is connected to the line and is powered up, the driver must not cause the differential signal to drop below 200mV. Figures 12, 13, and 14 show the results of the MAX3060E during power-up for three different V CC ramp rates (0.1V/s, 1V/s, and 10V/s). The photos show the VCC ramp, the single-ended signal on each side of the 100 termination, as well as the differential signal across the termination.
MAX3060E/MAX3061E/MAX3062E MAX3060E/MAX3061E/MAX3062E
5V VCC A 0 200mV/div
B
200mV/div
A-B
238mV 20mV/div 40s/div
15kV ESD Protection
As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against ESD encountered during handling and assembly. The MAX3060E family's receiver inputs/driver outputs (A, B) have extra protection against static electricity found in normal operation. Maxim's engineers developed stateof-the-art structures to protect these pins against 15kV ESD without damage. After an ESD event, the devices continue working without latchup. ESD protection can be tested in several ways. The receiver inputs are characterized for protection to the following: * 15kV using the Human Body Model * 7kV using the Contact Discharge method specified in IEC 1000-4-2 (formerly IEC 801-2) * 7kV using the Air-Gap Discharge method specified in IEC 1000-4-2 (formerly IEC 801-2)
Figure 12. Differential Power-Up Glitch (0.1V/s)
5V
VCC A
0
20mV/div
B
20mV/div 238mV 20mV/div 2s/div
A-B
Figure 13. Differential Power-Up Glitch (1V/s)
5.0V VCC VCC A DI VCC OR GND B 1k A-B 200ns/div 0.1k 50pF B 1k A
5V 0
50mV/div
50mV/div 238mV 20mV/div
Figure 11. Typical Offset Termination
Figure 14. Differential Power-Up Glitch (10V/s)
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13
15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
ESD Test Conditions ESD performance depends on a number of conditions. Contact Maxim for a reliability report that documents test setup, methodology, and results. Human Body Model Figure 15a shows the Human Body Model, and Figure 15b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the device through a 1.5k resistor. IEC 1000-4-2 The IEC 1000-4-2 standard covers ESD testing and performance of finished equipment; it does not specifically refer to integrated circuits. The main difference between tests done using the Human Body Model and IEC 1000-4-2 is higher peak current in IEC 1000-4-2. Because series resistance is lower in the IEC 1000-4-2 ESD test model (Figure 16), the ESD withstand voltage measured to this standard is generally lower than that measured using the Human Body Model. The Air-Gap test involves approaching the device with a charged probe. The Contact Discharge method connects the probe to the device before the probe is energized. Machine Model The Machine Model for ESD testing uses a 200pF storage capacitor and zero-discharge resistance. It mimics the stress caused by handling during manufacturing and assembly. All pins (not just RS-485 inputs) require this protection during manufacturing. Therefore, the Machine Model is less relevant to the I/O ports than are the Human Body Model and IEC 1000-4-2.
RC 1M CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE RD 1.5k DISCHARGE RESISTANCE DEVICE UNDER TEST
Cs 100pF
STORAGE CAPACITOR
Figure 15a. Human Body ESD Test Model
IP 100% 90% AMPERES 36.8% 10% 0 0 tRL TIME
Ir
PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE)
tDL CURRENT WAVEFORM
Figure 15b. Human Body Current Waveform
RC 50M to 100M CHARGE-CURRENT LIMIT RESISTOR HIGHVOLTAGE DC SOURCE
RD 330 DISCHARGE RESISTANCE DEVICE UNDER TEST
Applications Information
256 Transceivers on the Bus
The standard RS-485 receiver input impedance is 12k (one-unit load), and the standard driver can drive up to 32-unit loads. The MAX3060E family of transceivers have a 1/8-unit-load receiver input impedance (96k), allowing up to 256 transceivers to be connected in parallel on one communication line. Any combination of these devices and/or other RS-485 transceivers with a total of 32 unit loads or less can be connected to the line.
Cs 150pF
STORAGE CAPACITOR
Figure 16. IEC 1000-4-2 ESD Test Model
Reduced EMI and Reflections
The MAX3060E and MAX3061E are slew-rate limited, minimizing EMI and reducing reflections caused by improperly terminated cables. Figure 17 shows the driver output waveform and its Fourier analysis of a 25kHz
signal transmitted by a MAX3062E. High-frequency harmonic components with large amplitudes are evident. Figure 18 shows the same signal displayed for a MAX3061E transmitting under the same conditions.
14
______________________________________________________________________________________
15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT
Figure 18's high-frequency harmonic components are much lower in amplitude, compared with Figure 17's, and the potential for EMI is significantly reduced. Figure 19 shows the same signal displayed for a MAX3060E transmitting under the same conditions. Figure 19's high-frequency harmonic components are even lower. In general, a transmitter's rise time relates directly to the length of an unterminated stub, which can be driven with only minor waveform reflections. The following equation expresses this relationship conservatively: Length = tRISE / (10 x 1.5ns/ft) where tRISE is the transmitter's rise time. For example, the MAX3060E's rise time is typically 1850ns, which results in excellent waveforms with a stub length up to 123ft. A system can work well with longer unterminated stubs, even with severe reflections, if the waveform settles out before the UART samples them.
20dB/div
MAX3060E/MAX3061E/MAX3062E MAX3060E/MAX3061E/MAX3062E
0
125kHz/div
1.25MHz
Figure 17. Driver Output Waveform and FFT Plot of MAX3062E Transmitting a 25kHz Signal
Low-Power Shutdown Mode
Low-power shutdown mode is initiated by bringing both RE high and DE low. In shutdown, the devices typically draw only 1nA of supply current. RE and DE can be driven simultaneously. The parts are guaranteed not to enter shutdown if RE is high and DE is low for less than 50ns. If the inputs are in this state for at least 600ns, the parts are guaranteed to enter shutdown. Enable times t_ ZH and t_ ZL in the Switching Characteristics tables assume the part was not in a lowpower shutdown state. Enable times t_ZH(SHDN) and t_ZL(SHDN) assume the parts were shut down. It takes drivers and receivers longer to become enabled from low-power shutdown mode (t_ZH(SHDN), t_ZL(SHDN)) than from driver/receiver-disable mode (t_ZH, t_ZL).
20dB/div
0
125kHz/div
1.25MHz
Figure 18. Driver Output Waveform and FFT Plot of MAX3061E Transmitting a 25kHz Signal
Driver Output Protection
Two mechanisms prevent excessive output current and power dissipation caused by faults or by bus contention. The first, a foldback current limit on the output stage, provides protection after a 20s delay against short circuits over the whole common-mode voltage range (see Typical Operating Characteristics). The second, a thermal shutdown circuit, forces the driver outputs into a high-impedance state if the die temperature becomes excessive.
20dB/div
0
125kHz/div
1.25MHz
Figure 19. Driver Output Waveform and FFT Plot of MAX3060E Transmitting a 25kHz Signal ______________________________________________________________________________________ 15
15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
120 DI B 120 B DE
D
DE RO RE A B A B A A
D
DI
R R R D
R
RO RE
MAX3060E/MAX3061E/ MAX3062E (HALF-DUPLEX)
DI
D
DE
RO RE
DI
DE
RO RE
Figure 20. Typical Half-Duplex RS-485 Network
Typical Applications
The MAX3060E family of transceivers are designed for bidirectional data communications on multipoint bus transmission lines. Figure 20 shows a typical network application circuit. To minimize reflections, the line should be terminated at both ends in its characteristic impedance, and stub lengths off the main line should be kept as short as possible. The slew-rate-limited MAX3060E and MAX3061E are more tolerant of imperfect termination. TRANSISTOR COUNT: 669 PROCESS: CMOS
Chip Information
16
______________________________________________________________________________________
15kV ESD-Protected, Fail-Safe, 20Mbps, Slew-RateLimited RS-485/RS-422 Transceivers in a SOT MAX3060E/MAX3061E/MAX3062E
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
SOT23, 8L.EPS

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