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19-1519 Rev 0; 8/99
6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable
General Description
The MAX4447/MAX4448/MAX4449 single-ended-todifferential line drivers are designed for high-speed communications. Using current feedback for greater bandwidth, these devices deliver full-power bandwidths up to 405MHz and feature slew rates as high as 6500V/s. The MAX4447 has a fixed gain of +2V/V and a small-signal bandwidth of 430MHz. The MAX4448/ MAX4449 have small-signal bandwidths of 330MHz and 400MHz, respectively, and are internally compensated for minimum gain configurations of +2V/V and +5V/V, respectively. For greater design flexibility, the MAX4448/MAX4449 allow for variable gain selection using external gain-setting resistors. A low-power enable mode reduces current consumption below 5.5mA and places the outputs in a high-impedance state. The MAX4447/MAX4448/MAX4449 can deliver differential output swings of 6.2V from 5V supplies with a 50 load. Excellent differential gain/phase and noise specifications make these amplifiers ideal for a wide variety of video and RF signal-processing and transmission applications. o 6500V/s Slew Rate (MAX4449) o Small-Signal Bandwidth 430MHz (MAX4447) 330MHz (MAX4448) 400MHz (MAX4449) o 200MHz 0.1dB Gain Flatness (MAX4447) o 130mA Output Drive Current o +2V/V Internally Fixed Gain (MAX4447) o External Gain Selection +2V/V (MAX4448) +5V/V (MAX4449) o -78dB SFDR at 100kHz o Low Differential Gain/Phase: 0.01%/0.02 o Ultra-Low Noise: 23nV/Hz at fIN = 1MHz o 8ns Settling Time to 0.1%
Features
MAX4447/MAX4448/MAX4449
Applications
Differential Line Driver Single-Ended-to-Differential Conversion High-Speed Differential Transmitter Coaxial to Twisted-Pair Converter Differential Pulse Amplifier Differential ADC Driver xDSL Applications Video and RF Signal Processing and Transmission
PART MAX4447ESE MAX4448ESE MAX4449ESE
Ordering Information
TEMP. RANGE -40C to +85C -40C to +85C -40C to +85C PIN-PACKAGE 16 Narrow SO 16 Narrow SO 16 Narrow SO
Typical Operating Circuit
+5V
Pin Configuration
0.1F
TOP VIEW
VCC 1 VCC 2 N.C. 3 N.C. (RG) 4 IN 5 N.C. 6 VEE 7 VEE 8 16 GND 15 OUT14 VEE
75 75 INPUT 75 VCC IN EN OUT+ RT TO LOAD OUTRT 75
MAX4447 MAX4448 MAX4449
13 VEE 12 VEE 11 VEE 10 OUT+ 9 EN
MAX4447
VEE GND 0.1F
SO ( ) ARE FOR MAX4448/MAX4449 ONLY
-5V
________________________________________________________________ Maxim Integrated Products
1
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
ABSOLUTE MAXIMUM RATINGS
VCC to VEE ..........................................................................+12V Voltage on IN, EN, OUT+, OUT-, RG ....(VEE - 0.3V) to (VCC + 0.3V) Output Short-Circuit Duration to GND ...........................Indefinite Continuous Power Dissipation (TA = +70C) 16-Pin Narrow SO (derate 20mW/C above +70C) ...1600mW Operating Temperature Range ...........................-40C to +85C Storage Temperature Range ............................-65C to +150C Lead Temperature (soldering, 10sec) .............................+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, VEE = -5V, VEN 2V, VOUT = VOUT+ - VOUT- , RL = , TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25C.) PARAMETER Operating Supply Voltage Range Input Voltage Range Input Offset Voltage Input Offset Voltage Temperature Coefficient Input Bias Current Input Resistance Gain SYMBOL VCC VEE VIN VOS TCVOS IB RIN AV CONDITIONS VCC guaranteed by PSRR test VEE guaranteed by PSRR test Guaranteed by gain-error test VIN = 0 VIN = 0 VIN = 0 -3.0V VIN 3.0V MAX4447 -6V VOUT 6V MAX4448/MAX4449 (Note 1) MIN 4.5 -5.5 -6/AV 1.3 25 7 50 2 2 * (1+300/RG) 0.1 -0.3 -0.002 0.01 7.4 6.2 130 140 75 4 2 5 V/V 45 TYP MAX 5.5 -4.5 +6/AV 50 UNITS V V mV V/C A k
Gain Error Gain Drift Output Voltage Swing Output Current Drive Output Short-Circuit Current Power-Supply Rejection Ratio Output Leakage Current EN Logic Low Threshold EN Logic High Threshold EN Logic Input Low Current EN Logic Input High Current Quiescent Current VOUT IOUT ISC PSRR IOUT(OFF) VIL VIH IIL IIH IQ
MAX4447 MAX4448/MAX4449 MAX4447 VOUT = 0 MAX4448/MAX4449 RL = 100 between OUT+ and OUTRL = 50 between OUT+ and OUTRL = 20 between OUT+ and OUTShort circuit to GND VS = 4.5V to 5.5V VEN = 0, VOUT+ = VOUT- = 3.15V or -3.15V -6V VOUT 6V
% %/C V mA mA dB A V V A A mA
6.3 5.2 90 53
30 0.8 10 10 55 5.5
2 VEN = 0 VEN = 5V VIN = 0, VEN VIH VIN = 0, VEN VIL -2.5 0.8 46 3.2
2
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable
AC ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = -5V, RL = 100 between OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449, VOUT = VOUT+ - VOUT-, TA = +25C, unless otherwise noted.) PARAMETER Small-Signal -3dB Bandwidth SYMBOL BWSS CONDITIONS MAX4447 VOUT = 100mVp-p VOUT = 8Vp-p VOUT = 4Vp-p Large-Signal -3dB Bandwidth Large-Signal -3dB Bandwidth BWLS VOUT = 2Vp-p MAX4448 MAX4449 MAX4449 MAX4447 MAX4448 MAX4449 MAX4447 MAX4448 MAX4449 MAX4447 0.1dB Gain Flatness VOUT = 100mVp-p MAX4448 MAX4449 MAX4447 VOUT = 8V step MAX4448 MAX4449 MAX4447 Slew Rate (Note 2) SR VOUT = 4V step MAX4448 MAX4449 MAX4447 VOUT = 2V step MAX4448 MAX4449 MAX4447 VOUT = 8V step MAX4448 MAX4449 MAX4447 Rise Time (Note 2) tRISE VOUT = 4V step MAX4448 MAX4449 MAX4447 VOUT = 2V step MAX4448 MAX4449 MIN TYP 430 330 400 250 250 260 320 285 310 405 200 40 140 5700 4300 6500 3000 3000 3700 1700 1900 1800 670 1030 850 720 820 660 720 520 740 ps V/s MHz MHz MHz MAX UNITS
MAX4447/MAX4448/MAX4449
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3
6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V, VEE = -5V, RL = 100 between OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449, VOUT = VOUT+ - VOUT-, TA = +25C, unless otherwise noted.) PARAMETER SYMBOL VOUT = 8V step CONDITIONS MAX4447 MAX4448 MAX4449 MAX4447 Fall Time (Note 2) tFALL VOUT = 4V step MAX4448 MAX4449 MAX4447 VOUT = 2V step Settling Time fC = 100kHz Spurious-Free Dynamic Range SFDR VOUT = 2Vp-p fC = 5MHz fC = 20MHz fC = 100MHz fC = 100kHz 2nd Harmonic Distortion VOUT = 2Vp-p fC = 5MHz fC = 20MHz fC = 100MHz fC = 100kHz 3rd Harmonic Distortion VOUT = 2Vp-p fC = 5MHz fC = 20MHz fC = 100MHz Differential Phase Error Differential Gain Error Input Noise Voltage Density Input Noise Current Density Output Impedance Enable Time Disable Time Power-Up Time Power-Down Time tON tOFF DP DG eN iN ZOUT NTSC, RL = 150 NTSC, RL = 150 f = 1MHz (Note 3) f = 1MHz f = 10MHz, each output to ground VIN = 1V, VOUT settle to within 1% VIN = 1V, VOUT settle to within 1% VIN = 1V, VOUT settle to within 1% VIN = 1V, VOUT settle to within 1% MAX4448 MAX4449 MIN TYP 1100 900 900 900 810 780 800 770 660 8 -78 -78 -62 -46 -78 -78 -62 -46 -86 -86 -71 -54 0.02 0.01 24 1.8 1.0 55 0.4 0.08 0.5 degrees % nV/Hz pA/Hz ns s s s dBc dBc dBc ns ps MAX UNITS
Note 1: RG is the gain resistor. See Figure 1. Note 2: Input step voltage has <100ps rise (fall) time. Measured at the output from 10% to 90% (90% to 10%) levels. Note 3: Includes the current noise contribution through the on-die feedback resistor.
4
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable
Typical Operating Characteristics
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100 between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25C, unless otherwise noted.)
MAX4447 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC01
MAX4447/MAX4448/MAX4449
MAX4448 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC02
MAX4449 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
3 2 1 GAIN (dB) 0 -1 -2 -3 -4 -5 -6
MAX4447 TOC03
4 3 2 1 GAIN (dB)
4 3 2 1 GAIN (dB) 0 -1 -2 -3 -4 -5 -6
4
0 -1 -2 -3 -4 -5 -6 100k 1M 10M FREQUENCY (Hz) 100M 1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
MAX4447 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC04
MAX4448 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC05
MAX4449 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p)
0.4 0.3 0.2 GAIN (dB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5
MAX4447 TOC06
0.5 0.4 0.3 0.2 GAIN (dB)
0.5 0.4 0.3 0.2 GAIN (dB) 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5
0.5
0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 100k 1M 10M FREQUENCY (Hz) 100M 1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
MAX4447 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p)
MAX4447 TOC07
MAX4448 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p)
MAX4447 TOC08
MAX4449 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p)
3 2 1 GAIN (dB) 0 -1 -2 -3 -4 -5 -6
MAX4447 TOC09
4 3 2 1 GAIN (dB)
4 3 2 1 GAIN (dB) 0 -1 -2 -3 -4 -5 -6
4
0 -1 -2 -3 -4 -5 -6 100k 1M 10M FREQUENCY (Hz) 100M 1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
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5
6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100 between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25C, unless otherwise noted.)
MAX4447 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC10
MAX4448 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
MAX4447 TOC11
MAX4449 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p)
20 15 10 GAIN (dB) 5 0 -5 -10 -15 -20 -25 CLOAD = 5pF CLOAD = 15pF
MAX4447 TOC12
25 20 15 10 GAIN (dB) 5 0 -5 -10 -15 -20 -25 100k 1M 10M FREQUENCY (Hz) 100M CLOAD = 5pF CLOAD = 15pF
25 20 15 10 GAIN (dB) 5 0 -5 -10 -15 -20 -25 CLOAD = 5pF CLOAD = 15pF
25
1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
100k
1M
10M FREQUENCY (Hz)
100M
1G
MAX4447 SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC13
MAX4448 SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC14
MAX4449 SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC15
INPUT 50mV/div
INPUT 50mV/div
INPUT 25mV/div
OUTPUT 100mV/div
OUTPUT 100mV/div
OUTPUT 125mV/div
(5ns/div)
(5ns/div)
(5ns/div)
MAX4447 LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC16
MAX4448 LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC17
MAX4449 LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC18
INPUT 500mV/div
INPUT 500mV/div
INPUT 200mV/div
OUTPUT 1V/div
OUTPUT 1V/div
OUTPUT 1V/div
(5ns/div)
(5ns/div)
(5ns/div)
6
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100 between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25C, unless otherwise noted.)
SLEW RATE vs. OUTPUT VOLTAGE
MAX4447 TOC19
MAX4447/MAX4448/MAX4449
MAX4447 DIFFERENTIAL GAIN AND PHASE
MAX4447 TOC20
MAX4448 DIFFERENTIAL GAIN AND PHASE
DIFFERENTIAL GAIN (%) 0.002 0.000 -0.002 -0.004 -0.006 0 IRE 0.04 0.03 0.02 0.01 0 -0.01 0 10 20 30 40 50 60 70 80 90 100 IRE DIFFERENTIAL PHASE ()
MAX4447 TOC21
MAX4449 6000 MAX4447 SLEW RATE (V/s) 5000 4000 3000 2000 1000 0 0 2 4 6 8 10 MAX4448
DIFFERENTIAL GAIN (%)
7000
0.004 0.002 0.000 -0.002 -0.004 0 IRE 0.03 0.02 0.01 0 -0.01 0
100
100
DIFFERENTIAL PHASE ()
12
10 20 30 40 50 60 70 80 90 100 IRE
OUTPUT VOLTAGE (V)
MAX4449 DIFFERENTIAL GAIN AND PHASE
0.02 0.00 -0.02 -0.04 -0.06 -0.08 0 IRE 0.015 0.010 0.005 0.000 -0.005 0 10 20 30 40 50 60 70 80 90 100 IRE DIFFERENTIAL PHASE ()
MAX4447 TOC22
MAX4447 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p)
MAX4447 TOC23
MAX4448 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p)
-10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 -80 -90 -100 2ND 3RD
MAX4447 TOC24
DIFFERENTIAL GAIN (%)
0 -10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 -80 -90 -100 1M 10M FREQUENCY (Hz) 2ND 3RD
0
100
100M
1M
10M FREQUENCY (Hz)
100M
MAX4449 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p)
MAX4447 TOC25
MAX4447 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz)
MAX4447 TOC26
MAX4448 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz)
-10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 3RD 2ND
MAX4447 TOC27
0 -10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 -80 -90 -100 1M 10M FREQUENCY (Hz) 2ND 3RD
0 -10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 -80 -90 -100 3RD 2ND
0
-80 -90 -100
100M
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
OUTPUT VOLTAGE SWING (V)
OUTPUT VOLTAGE SWING (V)
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100 between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25C, unless otherwise noted.)
MAX4449 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz)
MAX4447 TOC28
VOLTAGE NOISE DENSITY vs. FREQUENCY
MAX4447 TOC29
CURRENT NOISE DENSITY vs. FREQUENCY
MAX4447 TOC30
0 -10 -20 DISTORTION (dB) -30 -40 -50 -60 -70 -80 -90 -100 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE SWING (V) 2ND 3RD
1000
100
VOLTAGE NOISE DENSITY (nV/ Hz)
CURRENT NOISE DENSITY (pA/ Hz)
100
10
10 1 10 100 1k 10k 100k 1M FREQUENCY (Hz)
1 1 10 100 1k 10k 100k 1M FREQUENCY (Hz)
ISOLATION RESISTANCE vs. CAPACITIVE LOAD
MAX4447 TOC31
OUTPUT IMPEDANCE vs. FREQUENCY
DIFFERENTIAL OUTPUT VOLTAGE SWING (Vp-p)
MAX4447 TOC32
DIFFERENTIAL OUTPUT VOLTAGE SWING vs. RESISTIVE LOAD
14 12 10 8 6 4 2 0 0 40 80 120 RL () 160 200
MAX4447 TOC33
22 20 18 16 14 12 10 0 20 40 60 80 100
100
16
ISOLATION RESISTANCE ()
CURRENT IMPEDANCE ()
10
1
0.1 120 100k 1M 10M FREQUENCY (Hz) 100M 1G CAPACITIVE LOAD (pF)
POWER-SUPPLY REJECTION vs. FREQUENCY
MAX4447 TOC34
SHUTDOWN RESPONSE TIME
EN VEN = 0.8V TO 2V VOS (mV)
MAX4447 TOC35
OFFSET VOLTAGE vs. TEMPERATURE
MAX4447 TOC36
0 -10 -20 -30 PSR (dB) -40 -50 -60 -70 -80 -90 0.1 1 10 FREQUENCY (MHz) 100
4 3 2 1 0 -1 -2 -3
OUTPUT VOLTAGE 1V/div
1000
(50ns/div)
-40
-15
10
35
60
85
TEMPERATURE (C)
8
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100 between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25C, unless otherwise noted.)
QUIESCENT CURRENT vs. TEMPERATURE
MAX4447 TOC37
INPUT BIAS CURRENT vs. TEMPERATURE
MAX4447 TOC38
50 EN = VCC QUIESCENT CURRENT (mA) 40
12
INPUT BIAS CURRENT (A) EN = GND -40 -15 10 35 60 85
9
30
6
20
10
3
0 TEMPERATURE (C)
0 -40 -15 10 35 60 85 TEMPERATURE (C)
Pin Description
PIN MAX4447 1, 2 3, 4, 6 -- 5 7, 8, 11, 12, 13, 14 9 10 15 16 MAX4448 MAX4449 1, 2 3, 6 4 5 7, 8, 11, 12, 13, 14 9 10 15 16 NAME FUNCTION
VCC N.C. RG IN VEE EN OUT+ OUTGND
Positive Power Supply. Bypass with a 0.1F capacitor to GND. No Connection. Not internally connected. Connect to GND for best AC performance. Gain-Set Resistor. Connect gain-setting resistor from RG to GND. Amplifier Noninverting Input Negative Power-Supply Input. Bypass with a 0.1F capacitor to GND. Active-High, TTL-Compatible, Enable Input. Connect to VCC for normal operation. Connect to GND for low-power operation. Positive Polarity Output Negative Polarity Output Ground
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9
6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
Detailed Description
The MAX4447/MAX4448/MAX4449 single-ended-to-differential converters are capable of transmitting highspeed signals such as T1 or xDSL over twisted-pair cable. Excellent gain and phase characteristics, along with low distortion, make these devices suitable for video and RF signal processing and transmission. These converters can be interfaced directly to some of Maxim's wireless products, such as the MAX2450/ MAX2451. The MAX4447/MAX4448/MAX4449 offer wide small-signal bandwidths of 430MHz, 330MHz, and 400MHz, respectively. Internally trimmed resistors minimize gain errors to under 2% over the full output range. Other features include a high slew rate up to 6500V/s and high output current (130mA), which allow these amplifiers to be used in numerous high-speed communications applications.
VCC
INPUT
IN OUT+
MAX4448 MAX4449
RG RGAIN
OUT300 AVCL = 2 ( 1 + RGAIN )
Applications Information
Grounding and Bypassing
Use high-frequency design techniques when designing the PC board for the MAX4447/MAX4448/MAX4449: * Use a multilayer board with one layer dedicated as the ground plane. * Do not wire-wrap or use breadboards, due to high inductance. * Avoid IC sockets, due to high parasitic capacitance and inductance. * Bypass supplies with 0.1F. Use surface-mount capacitors to minimize lead inductance. * Keep signal lines as short and straight as possible. Do not make 90 turns; round all corners. Do not cross signals if possible. * Ensure that the ground plane is free from voids.
INPUT IN OUT+
VEE
Figure 1. Setting the Amplifier Gain
VCC
RISO CLOAD
MAX4447 MAX4448 MAX4449
RG RGAIN
RISO OUTCLOAD
Output Short-Circuit Protection
Output short-circuit protection typically limits the current to 140mA when shorted to GND, thereby keeping the power dissipation under the absolute maximum power dissipating rating. However, when shorted to either supply, the short-circuit current can be significantly higher and cause damage to the device.
VEE
Figure 2. Using an Isolation Resistor for High Capacitive Loads
Low-Power Enable Mode
The MAX4447/MAX4448/MAX4449 are disabled when EN goes low. This reduces supply current to only 3.2mA and places the outputs into a higher impedance.
10
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6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
IN 500mV/div
IN 500mV/div
CL = 15pF OUT 1V/div OUT 1V/div
CL = 15pF
Figure 3. Capacitive-Loaded Output Step Response Without Isolation Resistor
Figure 4. Capacitive-Loaded Output Step Response with 14 Isolation Resistor
Setting Gain
The MAX4448/MAX4449 are stable with minimum gain of +2V/V and +5V/V, respectively. An external resistor, RGAIN, connected between RG and GND sets the gain of these devices. Calculate the gain as follows: Gain = 2 (1 + 300 / RGAIN) RGAIN for the MAX4449 must be 200.
Twisted-Pair Line Driver
The MAX4447/MAX4448/MAX4449 are well-suited to drive twisted-pair cables. The 24AWG telephone wire widely used produces losses at the higher frequencies. Compensate for these losses by increasing the gain slightly.
Driving Capacitive Loads
The MAX4447/MAX4448/MAX4449 are designed to drive capacitive loads. However, excessive capacitive loads may cause ringing or instability at the output as phase margin is reduced. Adding a small series isolation resistor at the output helps reduce the ringing but slightly increases gain error. TRANSISTOR COUNT: 291
Chip Information
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11
6500V/s, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447/MAX4448/MAX4449
Package Information
SOICN.EPS
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.
12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 (c) 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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