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(R)
Preliminary
SP3282EB
Intelligent +2.35V to +5.5V RS-232 Transceivers
FEATURES Operates over entire Li+ Battery range Interoperable with EIA/TIA-232-F and adheres to EIA/TIA-562 down to a +2.35V power supply AUTO ON-LINE(R) circuitry automatically wakes up from a 1A shutdown Minimum 250Kbps data rate Regulated charge pump yields stable RS-232 outputs regardless of VCC variations Unique VL for low logic compatibility regardless of VCC Enhanced ESD Specifications for all TTL and RS-232 I/O lines. +15kV Human Body Model +15kV IEC1000-4-2 Air Discharge +8kV IEC1000-4-2 Contact Discharge Enhanced battery life as the VCC drops below 3.1V
C2+ 1 GND 2 C2- 3 V- 4 T1OUT 5 T2OUT 6 T3OUT 7 R1IN 8 R2IN 9 T4OUT 10 R3IN 11 T5OUT 12 ONLINE 13 SHUTDOWN 14 SP3282EB 28 C1+ 27 26 25 V+ VCC C1-
24 T1IN 23 T2IN 22 T3IN 21 R1OUT 20 R2OUT
19 T4IN 18 17 16 R3OUT T5IN VL
15 STATUS
Now Available in Lead Free Packaging
APPLICATIONS Cell phone data cables PDAs, PDA cradles Hand held equipment Peripherals
DESCRIPTION
The SP3282EB device is an RS-232 transceiver solution intended for portable or hand-held applications such as notebook and palmtop computers, PDAs, cell phones and their data cables and cradles. The SP3282EB is compatible with low voltage logic down to 1.8V using a logic select pin (VL) which conditions the logic inputs and outputs to be compatible with system logic. The SP3282EB uses an internal high-efficiency, charge-pump power supply that requires only 0.1F capacitors in 3.3V operation. This charge pump and Sipex's driver architecture allow the SP3282EB device to deliver compliant RS-232 performance from a single +3.3V to +5.5Vpower supply and additionally adhere to EIA/TIA-562 driver outputs levels down to a power supply voltage of 2.35V. The AUTO ON-LINE(R) feature allows the device to automatically "wake-up" during a shutdown state when an RS-232 cable is connected and a connected peripheral is turned on. Otherwise, the device automatically shuts itself down drawing less than 1A. TABLE 1
Device SP3282EB Power Supplies 2.35V to 5.5V RS-232 Drivers 5 RS232 Receivers 3 External AUTO ON-LINE(R) Components Circuitry 4 yes Data No. of Rate Pins 250kbps 28
Applicable U.S. Patents - 5,306,954; and 6,378,026.
Date: 02/24/05 SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers (c) Copyright 2005 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability and cause permanent damage to the device. VCC......................................................-0.3V to +6.0V V+ (note 1).........................................-0.3V to +7.0V V- (note 1)..........................................+0.3V to -7.0V V+ + |V-| (note 1).............................................+13V ICC (DC VCC or GND current).........................+100mA Input Voltages VL........................................................-0.3V to +6.0V
TxIN, ONLINE, SHUTDOWN, .............0.3V to +6.0V RxIN..................................................................+25V Output Voltages TxOUT............................................................+13.2V RxOUT, STATUS.......................-0.3V to (VL + 0.3V) Short-Circuit Duration TxOUT.....................................................Continuous Storage Temperature......................-65C to +150C Power Dissipation per package 28-pin SSOP (derate 11.2mW/oC above +70oC)............900mW 28-pin TSSOP (derate 13.2mW/oC above +70oC).........1100mW
ELECTRICAL CHARACTERISTICS
VCC = +2.35 to +5.5V, VL=+1.8 to +5.5V, C1 - C4 = 0.22F. TA=TMIN to TMAX, unless otherwise noted. Typical values are at VCC=VL=+3.3V, and TA = +25C.)
PARAMETER SUPPLY CURRENT Supply Current, AUTO ON-LINE(R) Supply Current, Shutdown
MIN.
TYP. 1.0
MAX. 10
UNITS A
CONDITIONS All RxIN open, all TxIN at VLor GND, VCC=VL=+3.3V, TA=25C ONLINE = GND, SHUTDOWN = VL, All RxIN open, all TxIN at VL or GND VCC=VL=+3.3V, TA=25C ONLINE = VL or GND, SHUTDOWN = GND All TxIN at VL or GND, ONLINE = VL, VCC=VL=+3.3V, TA=25C SHUTDOWN = VL,no load TxIN, ONLINE, SHUTDOWN VL = +3.3V or +5.0V VL = +2.5V VL = +1.8V TxIN, ONLINE, SHUTDOWN VL = +5.0V VL = +3.3V VL = +2.5V VL = +1.8V TxIN, ONLINE, SHUTDOWN, TA = 25C RxOUT, Receivers disabled IOUT = +1.6mA, VL=2.5V, 3.3V, or 5.0V IOUT = +0.8mA, VL=1.8V IOUT = -1.0mA, VL=2.5V, 3.3V, 5.0V IOUT = -0.5mA, VL=1.8V TxOUT=5.0V to 3.7V TxOUT=3.7V to 5.0V
1.0
10
A
Supply Current, AUTO ON-LINE(R) Disabled
0.3
1.0
mA
LOGIC INPUTS AND RECEIVER OUTPUTS Input Logic Threshold LOW 0.8 0.6 0.4 Input Logic Threshold HIGH 2.4 2.0 1.4 0.9 Transmitter Input Hysteresis Input Leakage Current Output Leakage Current Output Voltage LOW Output Voltage HIGH DRIVER OUTPUTS VCC Mode Switch Point (VCC is Falling) VCC Mode Switch Point (VCC is Rising) VCC Mode Switch Point Hysteresis 2.95 3.3 3.1 3.5 400 3.25 3.7 V V mV VL - 0.6 VL - 0.6 VL - 0.1 VL - 0.1 0.3 0.01 0.05 1.0 10 0.4 0.4 V A A V V V V
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
2
ELECTRICAL CHARACTERISTICS
VCC = +2.35 to +5.5V, VL=+1.8 to +5.5V, C1 - C4 = 0.22F. TA=TMIN to TMAX, unless otherwise noted. Typical values are at VCC=VL=+3.3V, and TA = +25C.)
PARAMETER Output Voltage Swing
MIN.
TYP.
MAX.
UNITS
CONDITIONS All driver outputs loaded with 3K to GND, TA=25C VCC=3.25V to 5.5V, VCC=2.35 to 2.95V, VCC = V+ = V- = 0V, VTXOUT = 2V VTXOUT = GND VTXOUT=+/-12V, transmitter disabled, VCC=0V or 2.35V to 5.5V
5.0 +/-3.7 Output Resistance Output Short-Circuit Current Ouput Leakage Current RECEIVER INPUTS Input Voltage Range Input Threshold LOW -25 0.3 0.6 0.8 300
5.4
V
35
60 +/-25
mA A
25 0.8 1.2 1.5 1.0 1.5 1.8 0.3 1.8 2.4 2.4 7
V V VL=1.8V, TA=25C VL=2.5V or 3.3V, TA=25C VL=5.0V, TA=25C VL=1.8V, TA=25C VL=2.5V or 3.3V, TA=25C VL=5.0V, TA=25C TA=25C
HIGH
V
Input Hysteresis Input Resistance STATUS Output Voltage LOW HIGH Receiver Threshold to Drivers Enabled (tONLINE) Receiver +/- Threshold to Status HIGH (tSTSH) to Status LOW (tSTSL) AC Characteristics Maximum Data Rate Receiver Propagation Delay t PHL t PLH Receiver Output Enable Time Receiver Output Disable Time Time to Exit Shutdown Driver Skew |tPHL-tPLH| Receiver Skew |tPHL-tPLH| Transition-Region Slew Rate 250 VL - 0.6 3
V k
5
AUTO ON-LINE(R) CIRCUITRY CHARACTERISTICS (ONLINE = GND, SHUTDOWN = VCC) 0.4 VL-0.1 200 s V IOUT = 1.6mA, VL=2.5V, 3.3V, 5.0V or IOUT = +0.8mA, VL=1.8V IOUT = -1.0mA, VL=2.5V, 3.3V, 5.0V or IOUT = -0.5mA, VL=1.8V
20 20
s s kbps SP3282EB: RL = 3k, CL = 1000pF, one driver switching Receiver input to output, CL = 150pF
0.15 0.15 200 200 100 100 50
s ns ns s ns ns Normal operation Normal operation |VTXOUT|>3.7V, VCC=3.3V Measured at zero crossover Measured at zero crossover VCC = 3.3V, RL = 3k to 7k , TA = 25C, measurements taken from -3.0V to +3.0V or +3.0V to -3.0V CL = 150pF to 1000pF
30
V/s
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
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PIN DESCRIPTION
NAME C2+ GND C2VT1OUT T2OUT T3OUT R1IN R2IN T4OUT R3IN T5OUT ONLINE SHUTDOWN STATUS VL T5IN R3OUT T4IN R2OUT R1OUT T3IN T2IN T1IN C1VCC V+ C1+ FUNCTION Positive terminal of the symmetrical charge-pump capacitor C2. Ground. Negative terminal of the symmetrical charge-pump capacitor C2. Regulated -4.0V or -5.5V output generated by the charge pump. RS-232 driver output. RS-232 driver output. RS-232 driver output. RS-232 receiver input. RS-232 receiver input. RS-232 driver output. RS-232 receiver input. RS-232 driver output. Apply logic HIGH to override AUTO ON-LINE(R) circuitry keeping drivers active (SHUTDOWN must also be logic HIGH, refer to Table 2). Apply logic LOW to shut down drivers and charge pump. This overrides all AUTO ON-LINE(R) circuitry and ONLINE (refer to Table 2). TTL/CMOS Output indicating if a RS-232 signal is present on any Rx input. Logic level supply voltage selection TTL/CMOS driver input. TTL/CMOS receiver output. TTL/CMOS driver input. TTL/CMOS receiver output. TTL/CMOS receiver output. TTL/CMOS driver input. TTL/CMOS driver input. TTL/CMOS driver input. Negative terminal of the symmetrical charge-pump capacitor C1. +2.35V to +5.5V supply voltage. Regulated +4.0V or +5.5V output generated by the charge pump. Positive terminal of the symmetrical charge-pump capacitor C1 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 13 PIN NO. 1 2 3 4 5 6 7 8 9 10 11 12
Table 2. Device Pin Description
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
4
TYPICAL PERFOMANCE CHARACTERISTICS
Unless otherwise noted, the following perfomance characteristics apply for VCC = +4.2V, 250kbps data rate, all drivers loaded with 3k, 0.22F charge pump capacitors, and TAMB = +25C.
VCC + 26 VCC 28 C1+ 0.1F 25 C11 C2+ C2 + 0.1F 3 C224 T1IN 23 T2IN TTL/CMOS INPUTS 22 T3IN 19 T4IN 17 T5IN
T1OUT 5 T2OUT 6 T3OUT 7 T4OUT 10 T5OUT 12
C2+ 1 GND 2 C2- 3 V- 4 T1OUT 5 T2OUT 6 T3OUT 7 R1IN 8 R2IN 9 T4OUT 10 R3IN 11 T5OUT 12 ONLINE 13 SHUTDOWN 14 SP3282EB
28 C1+ 27 26 25 V+ VCC C1-
C5
0.1F
C1
+
V+
27 C3 + 0.1F
SP3282EB
V- 4 C4 + 0.1F
24 T1IN 23 T2IN 22 T3IN 21 R1OUT 20 R2OUT
RS-232 OUTPUTS
19 T4IN 18 17 16 R3OUT T5IN VL
VCC
21 R1OUT TTL/CMOS OUTPUTS 5k 20 R2OUT 5k 18 R3OUT 5k 14 13
Logic Level Select
R1IN R2IN R3IN
8 9 11 RS-232 INPUTS
SHUTDOWN ONLINE
15 STATUS
16 VL
GND 2
Figure 2. SP3282EB Pinout Configuration
Figure 3. SP3282EB Application Diagram
VCC + 26 VCC 28 C1+ 0.1F 25 C11 C2+ C2 + 0.1F 3 C224 T1IN 23 T2IN TTL/CMOS INPUTS 22 T3IN 19 T4IN 17 T5IN
T1OUT 5 T2OUT 6 T3OUT 7 T4OUT 10 T5OUT 12
C5
0.1F
C1
+
V+
27 C3 + 0.1F
SP3282EB
V-
4 C4 + 0.1F
RS-232 OUTPUTS
21 R1OUT TTL/CMOS OUTPUTS 5k 20 R2OUT 5k 18 R3OUT
VCC
R1IN R2IN R3IN
8 9 11 RS-232 INPUTS
5k 14 13
SHUTDOWN ONLINE
Logic Level Select
16 V L
GND 2
Figure 4. Circuit for the connectivity of the SP3282EB with a DB-9 connector
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
5
DESCRIPTION The SP3282EB device meets the EIA/TIA-232 and ITU-T V.28/V.24 communication protocols and can be implemented in battery-powered, portable, or hand-held applications such as notebook or palmtop computers. The SP3282EB device features Sipex's proprietary and patented (U.S. #5,306,954) on-board charge pump circuitry that generates 5.5V RS-232 voltage levels from a single +3.3V to +5.5V power supply. The SP3282EB will adhere to EIA/TIA-562 voltage levels with VCC as low as 2.35V. The SP3282EB device is an ideal choice for power sensitive designs. The SP3282EB device features AUTO ON-LINE(R) circuitry which reduces the power supply drain to a 1A supply current. In many portable or hand-held applications, an RS232 cable can be disconnected or a connected peripheral can be turned off. Under these conditions, the internal charge pump and the drivers will be shut down. Otherwise, the system automatically comes online. This feature allows design engineers to address power saving concerns without major design changes.
THEORY OF OPERATION The SP3282EB device is made up of four basic circuit blocks: 1. Drivers, 2. Receivers, 3. The Sipex proprietary charge pump, and 4. AUTO ON-LINE(R) circuitry. Drivers The drivers are inverting level transmitters that , when VCC is between +3.3V and +5.5V, convert TTL or CMOS logic levels to 5.0V EIA/TIA-232 levels with an inverted sense relative to the input logic levels . Typically, the RS-232 output voltage swing is +5.4V with no load and +5V minimum fully loaded. The driver outputs are protected against infinite short-circuits to ground without degradation in reliability. These drivers comply with the EIA-TIA-232F and all previous RS-232 versions. The driver outputs will adhere to EIA/ TIA-562 when VCC is as low as 2.35V. The SP3282EB drivers can guarantee a data rate of 250 kbps fully loaded with 3k in parallel with 1000pF, ensuring compatibility with PC-to-PC communication software. All unused driver inputs must be connected to VL or GND. Figure 6 shows a loopback test circuit used to test the SP3282EB RS-232 drivers. Figure 7 shows the test results of the loopback circuit with all five drivers active at 120kbps with typical RS-232 loads in parallel with 1000pF capacitors. Figure 8 shows the test results where one driver was active at 250kbps and all five drivers loaded with an RS232 receiver in parallel with a 1000pF capacitor. A solid RS-232 data transmission rate of 120kbps provides compatibility with many designs in personal computer peripherals and LAN applications. Receivers The receivers convert 5.0V EIA/TIA-232 levels to TTL or CMOS logic output levels. Receivers are not active when in shutdown. If there is no activity present at the receivers for a period longer than 100s during AUTO ONLINE(R) mode or when SHUTDOWN is enabled, the device goes into a standby mode where the circuit draws 1A. The truth table logic of the driver and receiver outputs can be found in Table 3.
VCC + 0.1F 28 C1+ 0.1F 25 C11 C2+ C2 + 0.1F 3 C224 T1IN 23 T2IN 22 T3IN 19 T4IN 17 T5IN
T1OUT 5 T2OUT 6 T3OUT 7 T4OUT 10 T5OUT 12
C5
26 VCC V+ 27 C3 + 0.1F
C1
+
SP3282EB
V- 4 C4 + 0.1F
RxD CTS DSR DCD RI
RS-232 OUTPUTS
UART or Serial C
TxD RTS DTR
VCC
21 R1OUT 5k 20 R2OUT 5k 18 R3OUT 5k 14 13 15
SHUTDOWN ONLINE STATUS
R1IN 8 R2IN
9
RS-232 INPUTS
R3IN 11
VL 16
GND 2
RESET
P Supervisor IC
VIN
Figure 5. Interface Circuitry Being Controlled by Microprocessor Supervisory Circuit
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
6
VCC +
C5
0.1F C1+ 0.1F C1C2+
VCC V+ C3 + 0.1F
C1
+
Since receiver input is usually from a transmission line where long cable lengths and system interference can degrade the signal, the inputs have a typical hysteresis margin of 300mV. This ensures that the receiver is virtually immune to noisy transmission lines. Should an input be left unconnected, an internal 5k pulldown resistor to ground will commit the output of the receiver to a HIGH state. Charge Pump The charge pump is a Sipex-patented design (U.S. #5,306,954) and uses a unique approach compared to older less-efficient designs. The charge pump uses a four-phase voltage shifting technique to attain symmetrical 5.5V power supplies. The internal power supply consists of a regulated dual charge pump that provides output voltages 5.5V regardless of the input voltage (VCC) over the +3.3V to +5.5V range. This is important to maintain compliant RS-232 levels regardless of power supply fluctuations. The charge pump will provide output voltage levels of 4.0V when the input voltage (VCC) is from +3.1V to +2.35V. The charge pump operates in a discontinuous mode using an internal oscillator. If the output voltages are less than a magnitude of 5.5V ( VCC > 3.3V ) and 4.0V (VCC < 3.1V), the charge pump is enabled. If the output voltages exceed a magnitude of 5.5V (VCC > 3.3V) and 4.0V (VCC < 3.1V), the charge pump is disabled. This oscillator controls the four phases of the voltage shifting (Figure 10). A description of each phase follows. Phase 1 (Figure 11)
SP3282EB
C2
+
VC4 + 0.1F
0.1F C2-
LOGIC INPUTS LOGIC OUTPUTS VCC
TxIN
TxOUT 1000pF
RxOUT 5k
RxIN
ONLINE SHUTDOWN GND
Figure 6. Loopback Test Circuit for RS-232 Driver Data Transmission Rates
Figure 7. Loopback Test Circuit Result at 120kbps (All Drivers Fully Loaded)
[ T ] +6V a) C2+
1 2 2
T
0V 0V
b) C2T -6V Ch1 2.00V Ch2 2.00V M 1.00s Ch1 1.96V
Figure 8. Loopback Test Circuit result at 250kbps (All Drivers Fully Loaded)
Date: 02/24/05
Figure 10. Charge Pump Waveforms
(c) Copyright 2005 Sipex Corporation
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
7
-- VSS charge storage -- During this phase of the clock cycle, the positive side of capacitors C1 and C2 are initially charged to VCC. Cl+ is then switched to GND and the charge in C1- is transferred to C2- . Since C2+ is connected to VCC, the voltage potential across capacitor C2 is now 2 times VCC. Phase 2 (Figure 12) -- VSS transfer -- Phase two of the clock connects the negative terminal of C2 to the VSS storage capacitor and the positive terminal of C2 to GND. This transfers a negative generated voltage to C 3 . This generated voltage is regulated to a minimum voltage of -5.5V (VCC > 3.3V) and -4.0V (VCC < 3.1V). Simultaneous with the transfer of the voltage to C3, the positive side of capacitor C1 is switched to VCC and the negative side is connected to GND. Phase 3 (Figure 13) -- VDD charge storage -- The third phase of the clock is identical to the first phase -- the charge transferred in C1 produces -VCC in the negative terminal of C1, which is applied to the negative side of capacitor C2. Since C2+ is at VCC, the voltage potential across C2 is 2 times VCC. Phase 4 (Figure 14) -- VDD transfer -- The fourth phase of the clock connects the negative terminal of C2 to GND, and transfers this positive generated voltage across C2 to C4, the VDD storage capacitor. This voltage is regulated to +5.5V (VCC > 3.3V) and +4.0V (VCC<3.1V). At this voltage, the internal oscillator is disabled. Simultaneous with the transfer of the voltage to C4, the positive side of capacitor C1 is switched to VCC and the negative side is connected to GND, allowing the charge pump cycle to begin again. The charge pump cycle will continue as long as the operational conditions for theinternal oscillator are present. Since both V+ and V- are separately generated
VCC
from VCC, in a no-load condition V+ and V- will be symmetrical. Older charge pump approaches that generate V- from V+ will show a decrease in the magnitude of V- compared to V+ due to the inherent inefficiencies in the design. The clock rate for the charge pump typically operates at 500kHz. The external capacitors should be 0.22F with a 16V working voltage rating for a VCC input range of +2.35V to +5.5V.
Charge Pump Capacitor Selection The charge pump capacitors C1-C4 and bypass C5 can be of any type including ceramic. If polarized capacitors are used, refer to figure 3 application diagram for proper orientation. The following chart illustrates the minimum capacitor valve for a given input voltage range.
VCC (V) 3.0 to 3.6 4.5 to 5.5 2.35 to 5.5 C1 and C5 (F) 0.1 0.047 0.22 C2,C3,C4 (F) 0.1 0.33 0.22
+VCC + C1 C2 + -VCC
C4 ++ C3
VDD Storage Capacitor VSS Storage Capacitor
-VCC
Figure 11. Charge Pump -- Phase 1
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
8
VCC
C4 ++ C1 C2 + + C3 -5.5V or -4.0V
VDD Storage Capacitor VSS Storage Capacitor
Figure 12. Charge Pump -- Phase 2
VCC
+VCC + C1 -VCC C2 + -VCC
C4 ++ C3
VDD Storage Capacitor VSS Storage Capacitor
Figure 13. Charge Pump -- Phase 3
VCC
+5.5V or +4.0V + C1 C2 + -
C4 ++ C3
VDD Storage Capacitor VSS Storage Capacitor
Figure 14. Charge Pump -- Phase 4
Inactive Detection Block
RXINACT
RECEIVER +2.7V 0V RS-232 INPUT VOLTAGES -2.7V VCC STATUS
S H U T D O W N
RXIN
RS-232 Receiver Block
RXOUT
0V
tSTSL tSTSH tONLINE
+5V DRIVER RS-232 OUTPUT VOLTAGES 0V -5V
Figure 15. Stage I of AUTO ON-LINE(R) Circuitry
Figure 17. AUTO ON-LINE(R) Timing Waveforms
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
9
Delay Stage
Delay Stage
Delay Stage
STATUS R1 INACT R2 INACT R3 INACT
Figure 16. Stage II of AUTO ON-LINE(R) Circuitry
SHUTDOWN INPUT HIGH HIGH HIGH LOW LOW
ONLINE INPUT HIGH LOW -
RS-232 SIGNAL AT RECEIVER INPUT YES NO NO YES NO
STATUS OUTPUT HIGH LOW LOW HIGH LOW
TXOUT Active Active High-Z High-Z High-Z
RXOUT Active Active Active High-Z High-Z
TRANSCEIVER STATUS Normal Operation Normal Operation
AUTO ON-LINE(R)
Mode Shutdown Shutdown
Table 3. AUTO ON-LINE(R) Logic
AUTO ON-LINE(R) Circuitry The SP3282EB device has a patent pending AUTO ON-LINE(R) circuitry on board that saves power in applications such as laptop computers, palmtop (PDA) computers, and other portable systems. The SP3282EB device incorporates an AUTO ON-LINE(R) circuit that automatically enables itself when the external transmitters are enabled and the cable is connected. Conversely, the AUTO ON-LINE(R) circuit also disables most of the internal circuitry when the device is not being used and goes into a standby mode where the device typically draws 1A. This function is controlled by the ONLINE pin. When this pin is tied to a logic LOW, the AUTO ON-LINE(R) function is active. Once active, the device is enabled until there is no activity on the receiver inputs. The receiver input typically sees at least +3V, which are generated from the transmitters at the other end of the cable with a +5V minimum. When the external transmitters are disabled or the cable is disconnected, the receiver inputs will be pulled down by their internal 5k resistors to ground. When this occurs over a period of time, the internal transmitters will be disabled and the device goes into a shutdown or standby mode. When ONLINE is HIGH, the AUTO ON-LINE(R) mode is disabled. The AUTO ON-LINE(R) circuit has two stages: 1) Inactive Detection 2) Accumulated Delay The first stage, shown in Figure 15, detects an inactive input. A logic HIGH is asserted on RXINACT if the cable is disconnected or the
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
10
external transmitters are disabled. Otherwise, RXINACT will be at a logic LOW. This circuit is duplicated for each of the other receivers. The second stage of the AUTO circuitry, shown in Figure 16, processes all the receiver's RXINACT signals with an accumulated delay that disables the device to a 1A supply current. The STATUS pin goes to a logic LOW when the cable is disconnected, or when the external transmitters are disabled. When the drivers or internal charge pump are disabled, the supply current is reduced to 1A. This can commonly occur in hand-held or portable applications where the RS-232 cable is disconnected or the RS-232 drivers of the connected peripheral are turned off. The AUTO ON-LINE(R) mode can be disabled by the SHUTDOWN pin. If this pin is a logic LOW, the AUTO ON-LINE(R) function will not operate regardless of the logic state of the ONLINE pin. Table 3 summarizes the logic of the AUTO ONLINE(R) operating modes and the truth table logic of the driver and receiver outputs. When the SP3282EB device is shut down, the charge pump is turned off. V+ charge pump output decays to VCC, the V- output decays to GND. The decay time will depend on the size of capacitors used for the charge pump. Once in shutdown, the time required to exit the shut down state and have valid V+ and V- levels is typically 200s. For easy programming, the STATUS pin can be used to indicate DTR or a Ring Indicator signal. Tying ONLINE and SHUTDOWN together will bypass the AUTO ON-LINE(R) circuitry so this connection acts like a shutdown input pin. ESD TOLERANCE The SP3282EB device incorporates ruggedized ESD cells on all driver output and receiver input pins. The ESD structure is improved over our previous family for more rugged applications and environments sensitive to electro-static discharges and associated transients. The improved ESD tolerance is at least +15kV without damage nor latchup. There are different methods of ESD testing applied:
Date: 02/24/05
a) MIL-STD-883, Method 3015.7 b) IEC1000-4-2 Air-Discharge c) IEC1000-4-2 Direct Contact
ON-LINE(R)
The Human Body Model has been the generally accepted ESD testing method for semiconductors. This method is also specified in MIL-STD-883, Method 3015.7 for ESD testing. The premise of this ESD test is to simulate the human body's potential to store electro-static energy and discharge it to an integrated circuit. The simulation is performed by using a test model as shown in Figure 18. This method will test the IC's capability to withstand an ESD transient during normal handling such as in manufacturing areas where the ICs tend to be handled frequently. The IEC-1000-4-2, formerly IEC801-2, is generally used for testing ESD on equipment and systems. For system manufacturers, they must guarantee a certain amount of ESD protection since the system itself is exposed to the outside environment and human presence. The premise with IEC1000-4-2 is that the system is required to withstand an amount of static electricity when ESD is applied to points and surfaces of the equipment that are accessible to personnel during normal usage. The transceiver IC receives most of the ESD current when the ESD source is applied to the connector pins. The test circuit for IEC10004-2 is shown on Figure 19. There are two methods within IEC1000-4-2, the Air Discharge method and the Contact Discharge method. With the Air Discharge Method, an ESD voltage is applied to the equipment under test (EUT) through air. This simulates an electrically charged person ready to connect a cable onto the rear of the system only to find an unpleasant zap just before the person touches the back panel. The high energy potential on the person discharges through an arcing path to the rear panel of the system before he or she even touches the system. This energy, whether discharged directly or through air, is predominantly a function of the discharge current rather than the discharge voltage. Variables with an air discharge such as approach speed of the object carrying the ESD potential to the system and humidity will tend to change the discharge current. For example, the rise time of the discharge current varies with the approach speed. The Contact Discharge Method applies the ESD current directly to the EUT. This method was
(c) Copyright 2005 Sipex Corporation
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
11
The circuit model in Figures 18 and 19 represent the typical ESD testing circuit used for all three methods. The CS is initially charged with the DC power supply when the first switch (SW1) is on. Now that the capacitor is charged, the second switch (SW2) is on while SW1 switches off. The voltage stored in the capacitor is then applied through RS, the current limiting resistor, onto the device under test (DUT). In ESD tests, the SW2 switch is pulsed so that the device under test receives a duration of voltage. For the Human Body Model, the current limiting resistor (RS) and the source capacitor (CS) are 1.5k an 100pF, respectively. For IEC-1000-4-2, the current limiting resistor (RS) and the source capacitor (CS) are 330 an 150pF, respectively.
RC C SW1
DC Power Source
30A
15A
0A t=0ns t Figure 20. ESD Test Waveform for IEC1000-4-2 t=30ns
i
RS S SW2 CS S
Device Under Test
Contact-Discharge Module
devised to reduce the unpredictability of the ESD arc. The discharge current rise time is constant since the energy is directly transferred without the air-gap arc. In situations such as hand held systems, the ESD charge can be directly discharged to the equipment from a person already holding the equipment. The current is transferred on to the keypad or the serial port of the equipment directly and then travels through the PCB and finally to the IC.
The higher CS value and lower RS value in the IEC1000-4-2 model are more stringent than the Human Body Model. The larger storage capacitor injects a higher voltage to the test point when SW2 is switched on. The lower current limiting resistor increases the current charge onto the test point.
Figure 18. ESD Test Circuit for Human Body Model
RC C SW1
DC Power Source
RS RS
RV SW2
CS S
Device Under Test
RS and RV add up to 330 for IEC1000-4-2. 330
Figure 19. ESD Test Circuit for IEC1000-4-2
Date: 02/24/05 SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers (c) Copyright 2005 Sipex Corporation
12
DEVICE PIN TESTED
Driver Outputs Receiver Inputs
HUMAN BODY MODEL
15kV 15kV
Air Discharge
15kV 15kV
IEC1000-4-2 Direct Contact
8kV 8kV
Level
4 4
Table 4. Transceiver ESD Tolerance Levels
PACKAGE: 28 PIN TSSOP
D e
O2
E1
E
Seaing Plane
O3
L L1
O1
1
2
DETAIL A
INDEX AREA D x E1 22
SEE DETAIL "A"
A2
A
Seating Plane
b A1
B B
28 Pin TSSOP JEDEC MO-153 (AE) Variation MIN NOM MAX SYMBOL A 1.2 A1 0.05 0.15 A2 0.8 1 1.05 b 0.19 0.3 c 0.09 0.2 D 9.6 9.7 9.8 0.65 BSC e E 6.40 BSC E1 4.3 4.4 4.5 L 0.45 0.6 0.75 L1 1.00 REF O1 0 8 12 REF O2 O3 12 REF Note: Dimensions in (mm)
b
C
Section B-B
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
13
PACKAGE: 28 PIN SSOP
D N
SEE DETAIL "A"
E1
E
1
2
INDEX AREA D x E1 22
2 NX R R1
Gauge Plane Seaing Plane L1 A
A
L
O
DETAIL A
28 Pin SSOP JEDEC MO-150 (AH) Variation MIN NOM MAX SYMBOL A 2 A1 0.05 A2 1.65 1.75 1.85 b 0.22 0.38 c 0.09 0.25 D 9.9 10.2 10.5 E 7.4 7.8 8.2 E1 5 5.3 5.6 L 0.55 0.75 0.95 1.25 REF L1 o 0 4 8 Note: Dimensions in (mm)
c
A2
A
Seating Plane
b A1
WITH LEAD FINISH
BASE METAL b
Section A-A
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
14
ORDERING INFORMATION
Model Temperature Range Package Types SP3282EBCA ................................................. 0C to +70C ..................................................... 28-pin SSOP SP3282EBCA/TR ............................................ 0C to +70C ..................................................... 28-pin SSOP SP3282EBCY .................................................. 0C to +70C ................................................... 28-pin TSSOP SP3282EBCY/TR ............................................ 0C to +70C ................................................... 28-pin TSSOP SP3282EBEA ................................................. 40C to +85C .................................................... 28-pin SSOP SP3282EBEA/TR ........................................... 40C to +85C .................................................... 28-pin SSOP SP3282EBEY ................................................. 40C to +85C .................................................. 28-pin TSSOP SP3282EBEY/TR ........................................... 40C to +85C .................................................. 28-pin TSSOP Available in lead free packaging. To order add "-L" suffix to part number. Example: SP3282EBEYTR = standard; SP3282EBEY-L/TR = lead free /TR = Tape and Reel Pack quantity is 1,500 for SSOP or TSSOP.
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Corporation
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Sipex Corporation Headquarters and Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described herein; neither does it convey any license under its patent rights nor the rights of others.
Date: 02/24/05
SP3282EB Intelligent +2.35V to +5.5V RS-232 Transceivers
(c) Copyright 2005 Sipex Corporation
15

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