View MAX3275_887706.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

19-2207; Rev 1; 3/05
Low-Noise, Fibre Channel Transimpedance Amplifiers
General Description
The MAX3275/MAX3277 transimpedance amplifiers provide a compact low-power solution for communication up to 2.125Gbps. They feature 300nA inputreferred noise at 2.1GHz bandwidth (BW) with 0.85pF input capacitance. The parts also have 2mA P-P AC input overload. The MAX3277 is identical to the MAX3275, but with the output polarities inverted for optimum packaging flexibility. Both parts operate from a single 3.3V supply and consume only 83mW. The MAX3275/MAX3277 are compact 24mil x 47mil die and require no external compensation capacitor. A space-saving filter connection is provided for positive bias to the photodiode through an on-chip 600 resistor to V CC. These features allow easy assembly into a TO-46 or TO-56 header with a photodiode. The MAX3275/MAX3277 and MAX3274 limiting amplifiers provide a two-chip solution for dual-rate, fibre channel receiver applications. o Up to 2.125Gbps (NRZ) Data Rates o 7psP-P Deterministic Jitter for <100AP-P Input Current o 300nARMS Input-Referred Noise at 2.1GHz Bandwidth o 25mA Supply Current at +3.3V o 2.3GHz Small-Signal Bandwidth o 2.0mAP-P AC Overload o Die Size: 24mil x 47mil
Features
MAX3275/MAX3277
Ordering Information
PART MAX3275U/D MAX3277U/D TEMP RANGE 0C to +85C 0C to +85C PIN-PACKAGE Dice* Dice*
Applications
Dual-Rate Fibre Channel Optical Receivers Gigabit Ethernet Optical Receivers
*Dice are guaranteed to operate from 0C to +85C, but are tested only at TA = +25C.
Typical Application Circuit
SMALL FORM FACTOR OPTICAL RECEIVER +3.3V +3.3V 4.7k TO 10k HOST SERVER OR SWITCH
400pF
600 CFILTER 400pF IN
VCC MAX3275 OUT+ TIA OUT0.1F GND 660 TH SQUELCH IN0.1F IN+ 100 MAX3274
LOS LOS 0.1F OUT+ LIMITING AMP OUT0.1F BWSEL RATE SELECT DESERIALIZER
100
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
Low-Noise, Fibre Channel Transimpedance Amplifiers MAX3275/MAX3277
ABSOLUTE MAXIMUM RATINGS
Power-Supply Voltage (VCC) .................................-0.5V to +4.0V Continuous CML Output Current (OUT+, OUT-) ...............................................-25mA to +25mA Continuous Input Current (IN)...............................-4mA to +4mA Continuous Input Current (FILTER).......................-8mA to +8mA Operating Junction Temperature Range (TJ) ....-55C to +150C Storage Ambient Temperature Range (TSTG) ...-55C to +150C Die Attach Temperature...................................................+400C
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.
ELECTRICAL CHARACTERISTICS
(VCC = +3.0V to +3.6V, TA = 0C to +85C. Typical values are at VCC = +3.3V, source capacitance (CIN) = 0.85pF, TA = +25C, unless otherwise noted.) (Notes 1, 2)
PARAMETER Supply Current Small-Signal Bandwidth Low-Frequency Cutoff Input Bias Voltage Input Resistance CIN = 0.6pF, BW = 0.8GHz (Notes 3, 4) CIN = 0.6pF, BW = 1.6GHz (Notes 3, 4) Input-Referred Noise IN CIN = 0.6pF, BW = 2.1GHz (Notes 3, 4) CIN = 0.85pF, BW = 0.8GHz (Notes 3, 4) CIN = 0.85pF, BW = 1.6GHz (Notes 3, 4) CIN = 0.85pF, BW = 2.1GHz (Notes 3, 4) AC Input Overload DC Input Overload Filter Resistance Output Resistance (OUT+, OUT-) Deterministic Jitter Transimpedance Transimpedance Linear Range Data Output Swing Output Data-Transition Time Output Return Loss Power-Supply Rejection PSR DJ (Notes 3, 5) (Note 5)
P-P
SYMBOL ICC BW
CONDITIONS Including output termination current -3dB, CIN = 0.6pF (Note 3) -3dB, CIN = 0.85pF (Note 3) -3dB, input current = 40A (Note 3)
MIN 2.0 1.7
TYP 25 2.7 2.3 65
MAX 41 3.3 2.7 1.0
UNITS mA GHz kHz V
40 185 245 275 193 272 300 2 1 510 42.5 600 50 15 15 7 2.8 50 220 300 90 15 10 40 34 500 140 3.3 690 57.5 40 31 16 3.8 250 350 380 275 400 430
nARMS
mAP-P mA psP-P k AP-P mVP-P ps dB dB
Single-ended 1mAP-P < input < 2mAP-P (Notes 3, 6, 7) 100AP-P < input 1mAP-P (Notes 3, 6, 7) 10AP-P < input 100AP-P (Notes 3, 6, 7) Differential output 0.95 < linearity < 1.05 (Note 8) Input > 100AP-P (Note 9) Input > 200AP-P, 20% to 80% rise/fall time (Notes 3, 10) Freq 1GHz 1GHz < freq 2GHz f < 1MHz (Note 11) 1MHz f < 10MHz (Note 11)
2
_______________________________________________________________________________________
Low-Noise, Fibre Channel Transimpedance Amplifiers
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +3.0V to +3.6V, TA = 0C to +85C. Typical values are at VCC = +3.3V, source capacitance (CIN) = 0.85pF, TA = +25C, unless otherwise noted.) (Notes 1, 2) Note 1: Die parameters are production tested at room temperature only, but are guaranteed by design and characterization from 0C to +85C. Note 2: Source capacitance represents the total capacitance at the IN pad during characterization of the noise and bandwidth parameters. Note 3: Guaranteed by design and characterization. Note 4: Measured using an RF-power meter with no pattern applied at the input. The TIA output is bandwidth limited for measurement using a 4th-order Bessel Thompson filter. The -3dB frequency of the filter matches the frequency (0.8GHz, 1.6GHz, or 2.1GHz) for the specified noise BW. Note 5: DC offset and deterministic jitter may exceed specification if AC or DC overload conditions are exceeded. Note 6: Using fibre channel K28.5 pattern. The input bandwidth is limited to 0.75 (2.125Gbps) by a 4th-order Bessel Thompson filter. Measured differentially across an AC-coupled 100 external load. Note 7: K28.5 pattern: (00111110101100000101). Note 8: Gain may vary 5% relative to reference measured with 30AP-P input. Note 9: Production tested with 1mAP-P input. Note 10: Using a K28.7 (0011111000) pattern. Measured differentially across an AC-coupled 100 external load. Note 11: Power-supply rejection PSR = -20log(VOUT/VCC), where VOUT is the differential output voltage and VCC is the noise on VCC.
MAX3275/MAX3277
Typical Operating Characteristics
(VCC = +3.3V, CIN = 0.85pF, TA = +25C, unless otherwise noted.)
INPUT-REFERRED NOISE vs. TEMPERATURE
350 340 330 320 310 300 290 280 270 260 250 240 230 220 210 200 0
MAX3275 toc01
INPUT-REFERRED NOISE vs. TEMPERATURE
MAX3275 toc02
FREQUENCY RESPONSE
71 TRANSIMPEDANCE (dB) 69 67 65 63 61 59
MAX3275 toc03
250 240 INPUT-REFERRED NOISE (nARMS) 230 220 210 200 190 180 170 160 150 BW = 0.8GHz CIN = 0.85pF CIN = 0.6pF CIN IS SOURCE CAPACITANCE PRESENTED TO DIE, INCLUDING PIN DIODE, AND PARASITIC INTERCONNECT CAPACITANCE
INPUT-REFERRED NOISE (nARMS)
CIN IS SOURCE CAPACITANCE PRESENTED TO DIE, INCLUDING PIN DIODE, AND PARASITIC INTERCONNECT CAPACITANCE
CIN = 0.85pF CIN = 0.6pF
BW = 1.6GHz 20 40 60 80 100
57 0 20 40 60 80 100 100M 1G FREQUENCY (Hz) 10G AMBIENT TEMPERATURE (C)
AMBIENT TEMPERATURE (C)
_______________________________________________________________________________________
3
Low-Noise, Fibre Channel Transimpedance Amplifiers MAX3275/MAX3277
Typical Operating Characteristics (continued)
(VCC = +3.3V, CIN = 0.85pF, TA = +25C, unless otherwise noted.)
DETERMINISTIC JITTER vs. INPUT AMPLITUDE
MAX3275 toc04
SMALL-SIGNAL TRANSIMPEDANCE vs. TEMPERATURE
74 73 72 71 70 69 68 67 66 65 64 63 62 61 60 0 20 40 60 80 AMBIENT TEMPERATURE (C)
MAX3275 toc05
BANDWIDTH vs. TEMPERATURE
2.9 2.8 BANDWIDTH (GHz) 2.7 2.6 2.5 2.4 2.3 2.2 2.1 2.0 100 0 20 40 60 80 100 AMBIENT TEMPERATURE (C) CIN = 0.85pF CIN = 0.6pF
MAX3275 toc06
50 45 DETERMINISTIC JITTER (psP-P) 40 35 30 25 20 15 10 5 0 0.01 0.1 1 2.125Gbps K28.5 INPUT
3.0
10
INPUT AMPLITUDE (mAP-P)
TRANSIMPEDANCE (dB)
EYE DIAGRAM (INPUT = 10AP-P)
MAX3275 toc07
EYE DIAGRAM (INPUT = 2mAP-P)
MAX3275 toc08
DIFFERENTIAL OUTPUT REFLECTION COEFFICIENT
-5 -10 S22 (dB) -15 -20 -25 -30 -35
MAX3275 toc09
0
5mV/div
50mV/div
INPUT: K28.5 80ps/div
INPUT: K28.5 80ps/div
-40 0 500M 1G 1.5G 2G 2.5G 3G FREQUENCY (Hz)
SUPPLY CURRENT vs. TEMPERATURE
45 40 SUPPLY CURRENT (mA) 35 30 25 20 15 10 5 0 0 20 40 60 80 100 AMBIENT TEMPERATURE (C) -150 -200 -200
MAX3275 toc10
DC TRANSFER FUNCTION (FILTER = GND)
150 OUTPUT VOLTAGE (mV) 100 50 0 -50 -100
MAX3275 toc11
50
200
-100
0
100
200
INPUT CURRENT (A)
4
_______________________________________________________________________________________
Low-Noise, Fibre Channel Transimpedance Amplifiers
Pad Description
MAX3275 BOND PAD 1, 9 2, 5 3 4 6 MAX3277 BOND PAD 1, 9 2, 5 4 3 6 NAME VCC GND OUTOUT+ N.C. Supply Voltage Circuit Ground Inverting Data Output. Current flowing into IN causes the voltage at OUT- to decrease. Noninverting Data Output. Current flowing into IN causes the voltage at OUT+ to increase. No Connection. Not internally connected. Provides bias voltage for the photodiode through a 600 resistor to VCC. When grounded, this pin disables the DC cancellation amplifier to allow a DC path from IN to OUT+ and OUT- for testing. TIA Input. Signal current from photodiode flows into this pin. FUNCTION
MAX3275/MAX3277
7
7
FILTER
8
8
IN
VCC Rf VOLTAGE AMPLIFIER IN TIA OUTPUT BUFFER 50 50 OUT+ OUT-
VCC VCC 600 FILTER DISABLE LOWPASS FILTER DC CANCELLATION GND
MAX3275 MAX3277
Figure 1. Functional Diagram
Detailed Description
The MAX3275/MAX3277 are transimpedance amplifiers designed for up to 2.125Gbps fibre channel applications. A functional diagram of the MAX3275/MAX3277 is shown in Figure 1. The MAX3275/MAX3277 comprises a transimpedance amplifier stage, a voltage amplifier stage, an output buffer, and a direct-current feedback cancellation circuit.
Transimpedance Amplifier Stage
The signal current at the input flows into the summing node of a high-gain amplifier. Shunt feedback through the resistor RF converts this current to a voltage. In parallel with the feedback are two back-to-back Schottky diodes that clamp the output signal for large input currents as shown in Figure 2.
Voltage Amplifier Stage
The voltage amplifier stage provides gain and converts the single-ended input to differential outputs.
_______________________________________________________________________________________
5
Low-Noise, Fibre Channel Transimpedance Amplifiers MAX3275/MAX3277
AMPLITUDE AMPLITUDE INPUT FROM PHOTODIODE
TIME OUTPUT (SMALL SIGNALS) INPUT (AFTER DC CANCELLATION) OUTPUT (LARGE SIGNALS)
TIME
Figure 2. MAX3275/MAX3277 Limited Output
Figure 3. DC Cancellation Effect on Input
Output Buffer
The output buffer provides a reverse-terminated voltage output. The buffer is designed to drive a 100 differential load between OUT+ and OUT-. The output current is divided between internal 50 resistors and the external load resistor. For optimum supply-noise rejection, the MAX3275/ MAX3277 should be terminated with a differential load. If a single-ended output is required, the unused output should be terminated in a similar manner. The MAX3275/MAX3277 will not drive a DC-coupled, 50 grounded load; however, it will drive a compatible 50 CML input.
average optical power and extinction ratio. Figure 4 and Table 1 show relations that are helpful for converting optical power to input signal when designing with the MAX3275/MAX3277. (Refer to Application note HFAN-3.0.0 Accurately Estimating Optical Receiver Sensitivity.)
Table 1. Optical Power Relations
PARAMETER Average Power Extinction Ratio Optical Power of a 1 Optical Power of a 0 Signal Amplitude SYMBOL PAVG re P1 P0 PIN RELATION PAVG = (P0 + P1)/2 re = P1/P0 P1 = 2PAVG(re)/(re + 1) P0 = 2PAVG/(re + 1) PIN = P1 - P0 PIN = 2PAVG(re - 1)/(re + 1)
DC Cancellation Circuit
The direct-current (DC) cancellation circuit uses lowfrequency feedback to remove the DC component of the input signal (Figure 3). This feature centers the input signal within the transimpedance amplifier's linear range, thereby reducing pulse-width distortion caused by large input signals. Pulse-width distortion in small signals will not be corrected. The DC cancellation circuit is internally compensated and therefore does not require external capacitors. This circuit minimizes pulse-width distortion for data sequences that exhibit a 50% mark density and 8b/10b coding. A mark density significantly different from 50% will cause the MAX3275/MAX3277 to generate pulsewidth distortion. DC cancellation current is drawn from the input and creates noise. For low-level signals with little or no DC component, the added noise is insignificant.
P1
OPTICAL POWER
PAVG
P0
TIME
Applications Information
Optical Power Relations
Many of the MAX3275/MAX3277 specifications relate to the input signal amplitude. When working with optical receivers, the input is sometimes expressed in terms of
Figure 4. Optical Power Relations
Optical Sensitivity Calculation
The input-referred RMS noise current (I N ) of the MAX3275/MAX3277 generally determines the receiver
6
_______________________________________________________________________________________
Low-Noise, Fibre Channel Transimpedance Amplifiers
sensitivity. To obtain a system bit error rate (BER) of 1E12, the signal-to-noise ratio must always exceed 14.1. The input sensitivity, expressed in average power, can be estimated as: 14.1IN (re +1) x 1000 Sensitivity =10 log dBm 2(re -1) where is the photodiode responsivity in A/W and IN is RMS current in Amps. form using chip and wire technology provides the best possible performance. Figure 5 shows a suggested layout for a TO header for the MAX3275/MAX3277. Special care should be taken to ensure that ESD at IN does not exceed 500V.
MAX3275/MAX3277
Photodiode Filter
Supply voltage noise at the cathode of the photodiode produces a current I = CPD V/t, which reduces the receiver sensitivity (C PD is the photodiode capacitance). The filter resistor of the MAX3275/MAX3277, combined with an external capacitor, can be used to reduce this noise (see the Typical Application Circuit). Current generated by supply noise voltage is divided between CFILTER and CPD. The input noise current due to supply noise is (assuming the filter capacitor is much larger than the photodiode capacitance): INOISE = (VNOISE)(CPD) / (RFILTER)(CFILTER) If the amount of tolerable noise is known, the filter capacitor can be easily selected: CFILTER = (VNOISE)(CPD) / (RFILTER)(INOISE) For example, with maximum noise voltage = 100mVP-P, CPD = 0.85pF, RFILTER = 600, and INOISE selected to be 350nA: CFILTER = (100mV)(0.85pF) / (600)(350nA) = 400pF
Input Optical Overload
The overload is the largest input that the MAX3275/ MAX3277 accept while meeting specifications. The optical overload can be estimated in terms of average power with the following equation: (2E - 3) (re +1) x 1000 Overload=10 log dBm 2(re -1)
Optical Linear Range
The MAX3275/MAX3277 have high gain, which limits the output when the input signal exceeds 50AP-P. The MAX3275/MAX3277 operate in a linear range (10% linearity) for inputs not exceeding: (50E - 6) (re +1) x 1000 Linear Range=10 log dBm 2(re -1)
Layout Considerations
Noise performance and bandwidth will be adversely affected by capacitance at the IN pad. Minimize capacitance on this pad and select a low-capacitance photodiode. Assembling the MAX3275/MAX3277 in die
Wire Bonding
For high-current density and reliable operation, the MAX3275/MAX3277 use gold metalization. Connections to the die should be made with gold wire only, using ball-bonding techniques. Wedge bonding is not recommended. Die thickness is typically 15 mils (0.4mm).
Pad Coordinates
VCC CFILTER
PHOTODIODE
PAD# 1 2
CAP
COORDINATES (m) 16, 39 16, 372 16, 806 358, 806 358, 341 358, 36 362, -116 250, -116 138, -116
3 4 5 6 7
OUT+
OUT-
OUTPUT POLARITIES REVERSED FOR MAX3277
MAX3275
CASE IS GROUND
8 9
Figure 5. Suggested Layout for TO-46 Header _______________________________________________________________________________________ 7
Low-Noise, Fibre Channel Transimpedance Amplifiers MAX3275/MAX3277
Chip Topographies
OUT(PAD 3) OUT+ (PAD 4)
MAX3275
GND (PAD 2)
GND (PAD 5) 0.047" (1.2mm)
VCC (PAD 1) INDEX
N.C. (PAD 6)
FILTER (PAD 7)
VCC (PAD 9)
IN (PAD 8)
0.024" (0.6mm)
8
_______________________________________________________________________________________
Low-Noise, Fibre Channel Transimpedance Amplifiers
Chip Topographies (continued)
OUT+ (PAD 3) OUT(PAD 4)
MAX3275/MAX3277
MAX3277
GND (PAD 2)
GND (PAD 5)
0.047" (1.2mm)
VCC (PAD 1) INDEX
N.C. (PAD 6)
FILTER (PAD 7)
VCC (PAD 9)
IN (PAD 8)
0.024" (0.6mm)
Chip Information
TRANSISTOR COUNT: 301 SUBSTRATE: ISOLATED PROCESS: SiGe BIPOLAR
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 _____________________ 9 (c) 2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.

▲Up To Search▲

Price & Availability of MAX3275

	To Download MAX3275 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .