General Description
The MAX4447/MAX4448/MAX4449 single-ended-to-
differential 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/µs. 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 compen-
sated 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 differen-
tial output swings of ±6.2V from ±5V supplies with a
50Ωload. Excellent differential gain/phase and noise
specifications make these amplifiers ideal for a wide
variety of video and RF signal-processing and transmis-
sion applications.
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
Features
♦6500V/µs Slew Rate (MAX4449)
♦Small-Signal Bandwidth
430MHz (MAX4447)
330MHz (MAX4448)
400MHz (MAX4449)
♦200MHz 0.1dB Gain Flatness (MAX4447)
♦130mA Output Drive Current
♦+2V/V Internally Fixed Gain (MAX4447)
♦External Gain Selection
≥+2V/V (MAX4448)
≥+5V/V (MAX4449)
♦-78dB SFDR at 100kHz
♦Low Differential Gain/Phase: 0.01%/0.02°
♦Ultra-Low Noise: 23nV/√Hz at fIN = 1MHz
♦8ns Settling Time to 0.1%
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
________________________________________________________________ Maxim Integrated Products 1
0.1µF
0.1µF
+5V
MAX4447
75Ω
TO
LOAD
75Ω
RT
RT
OUT+
OUT-
GND
VEE
VCC
EN
-5V
75Ω
INPUT
75Ω
IN
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
VCC GND
OUT-
VEE
VEE
VEE
VEE
OUT+
EN
TOP VIEW
MAX4447
MAX4448
MAX4449
SO
VCC
N.C.
N.C.
N.C. (RG)
IN
VEE
VEE
( ) ARE FOR MAX4448/MAX4449 ONLY
Typical Operating Circuit
19-1519 Rev 1; 10/99
PART
MAX4447ESE
MAX4448ESE -40°C to +85°C
-40°C to +85°C
TEMP. RANGE PIN-PACKAGE
16 Narrow SO
16 Narrow SO
Pin Configuration
Ordering Information
MAX4449ESE -40°C to +85°C 16 Narrow SO
EVALUATION KIT
AVAILABLE
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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= +25°C.)
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.
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= +70°C)
16-Pin Narrow SO (derate 20mW/°C above +70°C) ..1600mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
VIN = 0, VEN ≤VIL
VEN = 5V
Guaranteed by gain-error test
VEN = 0
VEE guaranteed by PSRR test
VCC guaranteed by PSRR test
VEN = 0, VOUT+ = VOUT- = 3.15V or -3.15V
VS= ±4.5V to ±5.5V
Short circuit to GND
RL= 20Ωbetween OUT+ and OUT-
RL= 50Ωbetween OUT+ and OUT-
-3.0V ≤VIN ≤3.0V
VIN = 0
VIN = 0
RL= 100Ωbetween OUT+ and OUT-
VIN = 0
CONDITIONS
3.2 5.5
IQ
Quiescent Current mA
46 55
µA0.8 10IIH
EN Logic Input High Current
µA-2.5 10IIL
EN Logic Input Low Current
V2VIH
EN Logic High Threshold
V0.8VIL
EN Logic Low Threshold
µA430IOUT(OFF)
Output Leakage Current
dB53 75PSRRPower-Supply Rejection Ratio
mA140ISC
Output Short-Circuit Current
mA90 130IOUT
Output Current Drive
V
±5.2 ±6.2
VOUT
Output Voltage Swing ±6.3 ±7.4
V-6/AV+6/AV
VIN
Input Voltage Range
V
-5.5 -4.5VEE
4.5 5.5VCC
Operating Supply Voltage
Range
2
kΩ50RIN
Input Resistance
mV1.3 50VOS
Input Offset Voltage
µV/°C25TCVOS
Input Offset Voltage
Temperature Coefficient
µA745IB
Input Bias Current
UNITSMIN TYP MAXSYMBOLPARAMETER
MAX4447
-6V ≤VOUT ≤6VAVMAX4448/MAX4449
(Note 1)
Gain V/V
2 ×(1+300/RG)
VIN = 0, VEN ≥VIH
-6V ≤VOUT ≤6V %
0.1 2
Gain Error
VOUT = 0 %/°C
-0.002
Gain Drift
MAX4447
MAX4447
MAX4448/MAX4449
MAX4448/MAX4449
-0.3 5
0.01
Large-Signal -3dB Bandwidth
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
_______________________________________________________________________________________ 3
AC ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = -5V, RL= 100Ωbetween OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449,
VOUT = VOUT+ - VOUT-, TA= +25°C, unless otherwise noted.)
VOUT = 100mVp-p
CONDITIONS
MHz
400
BWSS
Small-Signal -3dB Bandwidth 330
430
UNITSMIN TYP MAXSYMBOLPARAMETER
MAX4447
MAX4448
MAX4449
250MAX4449
VOUT = 2Vp-p
MHz
405
VOUT = 4Vp-p
310
285MAX4447
MAX4448
MAX4449
320
260
250MAX4447
MAX4448
MAX4449
VOUT = 8V step
6500
VOUT = 100mVp-p
SRSlew Rate (Note 2)
4300
5700MAX4447
MAX4448
MAX4449
VOUT = 2V step
V/µs
1800
VOUT = 4V step
1900
1700MAX4447
MAX4448
MAX4449
3700
3000
3000MAX4447
MAX4448
MAX4449
MHz
140
0.1dB Gain Flatness 40
200MAX4447
MAX4448
MAX4449
VOUT = 8V step
850
tRISE
Rise Time (Note 2)
1030
670MAX4447
MAX4448
MAX4449
VOUT = 2V step
ps
740
VOUT = 4V step
520
720MAX4447
MAX4448
MAX4449
660
820
720MAX4447
MAX4448
MAX4449
VOUT = 8Vp-p
BWLS
Large-Signal -3dB Bandwidth
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
4 _______________________________________________________________________________________
Note 1: RGis 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.
AC ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V, VEE = -5V, RL= 100Ωbetween OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449,
VOUT = VOUT+ - VOUT-, TA= +25°C, unless otherwise noted.)
µs
nV/√Hz
pA/√Hz
VOUT = 4V step
780
VOUT = 8V step
810
900MAX4447
MAX4448
MAX4449
VOUT = 2V step
660
CONDITIONS
tFALL
Fall Time (Note 2)
770
800MAX4447
MAX4448
MAX4449
-78
8
fC= 5MHz
ps
900
900
1100
UNITSMIN TYP MAXSYMBOLPARAMETER
MAX4447
MAX4448
MAX4449
dBc
Settling Time
-46
-62fC= 20MHz
fC= 100MHz
NTSC, RL= 150Ω
NTSC, RL= 150Ω
0.01DGDifferential Gain Error
0.02DP
-46
2nd Harmonic Distortion
Differential Phase Error
fC= 100MHz
-62
-78
-78fC= 100kHz
fC= 5MHz
fC= 20MHz
VIN = 1V, VOUT settle to within 1%
VIN = 1V, VOUT settle to within 1%
VIN = 1V, VOUT settle to within 1%
0.08tON
Power-Up Time
µs0.4
ns55Enable Time
Disable Time
VIN = 1V, VOUT settle to within 1%
f = 10MHz, each output to ground
f = 1MHz
f = 1MHz (Note 3)
Ω1.0ZOUT±
Output Impedance
%
1.8iN
24eN
Input Noise Voltage Density
Input Noise Current Density
µs
0.5tOFF
Power-Down Time
VOUT = 2Vp-p
-54
3rd Harmonic Distortion
fC= 100MHz
-71
-86
-86fC= 100kHz
fC= 5MHz
fC= 20MHz
ns
-78fC= 100kHz
VOUT = 2Vp-pSFDRSpurious-Free Dynamic Range dBc
degrees
Settle to 0.1%, VOUT = 2V step
VOUT = 2Vp-p dBc
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
_______________________________________________________________________________________ 5
4
-6
100k 1M 10M 100M 1G
MAX4447
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-4
MAX4447 TOC01
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
4
-6
100k 1M 10M 100M 1G
MAX4448
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-4
MAX4447 TOC02
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
4
-6
100k 1M 10M 100M 1G
MAX4449
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-4
MAX4447 TOC03
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
0.5
-0.5
100k 1M 10M 100M 1G
MAX4447
GAIN FLATNESS vs. FREQUENCY
(VOUT = 100mVp-p)
-0.3
MAX4447 TOC04
FREQUENCY (Hz)
GAIN (dB)
-0.1
0.1
0.3
0.4
-0.4
-0.2
0
0.2
0.5
-0.5
100k 1M 10M 100M 1G
MAX4448
GAIN FLATNESS vs. FREQUENCY
(VOUT = 100mVp-p)
-0.3
MAX4447 TOC05
FREQUENCY (Hz)
GAIN (dB)
-0.1
0.1
0.3
0.4
-0.4
-0.2
0
0.2
0.5
-0.5
100k 1M 10M 100M 1G
MAX4449
GAIN FLATNESS vs. FREQUENCY
(VOUT = 100mVp-p)
-0.3
MAX4447 TOC06
FREQUENCY (Hz)
GAIN (dB)
-0.1
0.1
0.3
0.4
-0.4
-0.2
0
0.2
4
-6
100k 1M 10M 100M 1G
MAX4447
LARGE-SIGNAL GAIN vs. FREQUENCY
(VOUT = 2Vp-p)
-4
MAX4447 TOC07
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
4
-6
100k 1M 10M 100M 1G
MAX4448
LARGE-SIGNAL GAIN vs. FREQUENCY
(VOUT = 2Vp-p)
-4
MAX4447 TOC08
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
4
-6
100k 1M 10M 100M 1G
MAX4449
LARGE-SIGNAL GAIN vs. FREQUENCY
(VOUT = 2Vp-p)
-4
MAX4447 TOC09
FREQUENCY (Hz)
GAIN (dB)
-2
0
2
3
-5
-3
-1
1
Typical Operating Characteristics
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ωbetween OUT+ and OUT-, AV= +2V/V for MAX4447/MAX4448,
AV= +5V/V for MAX4449, TA= +25°C, unless otherwise noted.)
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
6 _______________________________________________________________________________________
25
-25
100k 1M 10M 100M 1G
MAX4447
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-15
MAX4447 TOC10
FREQUENCY (Hz)
GAIN (dB)
-5
5
15
20
-20
-10
0
10 CLOAD = 15pF
CLOAD = 5pF
25
-25
100k 1M 10M 100M 1G
MAX4448
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-15
MAX4447 TOC11
FREQUENCY (Hz)
GAIN (dB)
-5
5
15
20
-20
-10
0
10 CLOAD = 15pF
CLOAD = 5pF
25
-25
100k 1M 10M 100M 1G
MAX4449
SMALL-SIGNAL GAIN vs. FREQUENCY
(VOUT = 100mVp-p)
-15
MAX4447 TOC12
FREQUENCY (Hz)
GAIN (dB)
-5
5
15
20
-20
-10
0
10 CLOAD = 15pF
CLOAD = 5pF
MAX4447
SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC13
(5ns/div)
INPUT
50mV/div
OUTPUT
100mV/div
MAX4448
SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC14
(5ns/div)
INPUT
50mV/div
OUTPUT
100mV/div
MAX4449
SMALL-SIGNAL PULSE RESPONSE
MAX4447 TOC15
(5ns/div)
INPUT
25mV/div
OUTPUT
125mV/div
MAX4447
LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC16
(5ns/div)
INPUT
500mV/div
OUTPUT
1V/div
MAX4448
LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC17
(5ns/div)
INPUT
500mV/div
OUTPUT
1V/div
MAX4449
LARGE-SIGNAL PULSE RESPONSE
MAX4447 TOC18
(5ns/div)
INPUT
200mV/div
OUTPUT
1V/div
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ωbetween OUT+ and OUT-, AV= +2V/V for MAX4447/MAX4448,
AV= +5V/V for MAX4449, TA= +25°C, unless otherwise noted.)
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
_______________________________________________________________________________________ 7
0
2000
1000
4000
3000
6000
5000
7000
046281012
SLEW RATE
vs. OUTPUT VOLTAGE
MAX4447 TOC19
OUTPUT VOLTAGE (V)
SLEW RATE (V/µs)
MAX4449
MAX4447
MAX4448
0.000
0.004
0.002
-0.002
-0.004
-0.01
0 102030405060708090100
0100
MAX4447
DIFFERENTIAL GAIN AND PHASE
0.01
0
IRE
IRE
DIFFERENTIAL
PHASE (°)
DIFFERENTIAL
GAIN (%)
0.03
0.02
MAX4447 TOC20
0.000
0.002
-0.002
-0.004
-0.006
-0.01
0 100
MAX4448
DIFFERENTIAL GAIN AND PHASE
0.01
0
IRE
IRE
DIFFERENTIAL
PHASE (°)
DIFFERENTIAL
GAIN (%)
0.03
0.04
0.02
MAX4447 TOC21
0 102030405060708090100
0.00
0.02
-0.02
-0.04
-0.06
-0.08
-0.005
0100
MAX4449
DIFFERENTIAL GAIN AND PHASE
0.000
IRE
IRE
DIFFERENTIAL
PHASE (°)
DIFFERENTIAL
GAIN (%)
0.010
0.015
0.005
MAX4447 TOC22
0 102030405060708090100
0
-100
1M 10M 100M
MAX4447
HARMONIC DISTORTION vs. FREQUENCY
(VOUT = 2Vp-p)
-80
-90
MAX4447 TOC23
FREQUENCY (Hz)
DISTORTION (dB)
-60
-70
-40
-30
-50
-20
-10
2ND
3RD
0
-100
1M 10M 100M
MAX4448
HARMONIC DISTORTION vs. FREQUENCY
(VOUT = 2Vp-p)
-80
-90
MAX4447 TOC24
FREQUENCY (Hz)
DISTORTION (dB)
-60
-70
-40
-30
-50
-20
-10
2ND
3RD
0
-100
1M 10M 100M
MAX4449
HARMONIC DISTORTION vs. FREQUENCY
(VOUT = 2Vp-p)
-80
-90
MAX4447 TOC25
FREQUENCY (Hz)
DISTORTION (dB)
-60
-70
-40
-30
-50
-20
-10
2ND
3RD
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
0 2341 5678
MAX4447
HARMONIC DISTORTION vs. OUTPUT
VOLTAGE SWING (fC = 5MHz)
MAX4447 TOC26
OUTPUT VOLTAGE SWING (V)
DISTORTION (dB)
2ND
3RD
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
0 2341 5678
MAX4448
HARMONIC DISTORTION vs. OUTPUT
VOLTAGE SWING (fC = 5MHz)
MAX4447 TOC27
OUTPUT VOLTAGE SWING (V)
DISTORTION (dB)
2ND
3RD
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ωbetween OUT+ and OUT-, AV= +2V/V for MAX4447/MAX4448,
AV= +5V/V for MAX4449, TA= +25°C, unless otherwise noted.)
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
8 _______________________________________________________________________________________
-100
-80
-90
-60
-70
-40
-50
-30
-10
-20
0
0 2341 5678
MAX4449
HARMONIC DISTORTION vs. OUTPUT
VOLTAGE SWING (fC = 5MHz)
MAX4447 TOC28
OUTPUT VOLTAGE SWING (V)
DISTORTION (dB)
2ND
3RD
1000
10
1 1k 10k 100k10 100 1M
VOLTAGE NOISE DENSITY
vs. FREQUENCY
100
MAX4447 TOC29
FREQUENCY (Hz)
VOLTAGE NOISE DENSITY (nV/ Hz)
100
1
1 1k 10k 100k10 100 1M
CURRENT NOISE DENSITY
vs. FREQUENCY
10
MAX4447 TOC30
FREQUENCY (Hz)
CURRENT NOISE DENSITY (pA/ Hz)
10
14
12
18
16
20
22
0608020 40 100 120
ISOLATION RESISTANCE
vs. CAPACITIVE LOAD
MAX4447 TOC31
CAPACITIVE LOAD (pF)
ISOLATION RESISTANCE (Ω)
100
0.1
100k 10M 100M 1G
OUTPUT IMPEDANCE
vs. FREQUENCY
1
10
MAX4447 TOC32
FREQUENCY (Hz)
CURRENT IMPEDANCE (Ω)
1M
0
2
4
6
8
10
12
14
16
0 40 80 120 160 200
DIFFERENTIAL OUTPUT VOLTAGE SWING
vs. RESISTIVE LOAD
MAX4447 TOC33
RL (Ω)
DIFFERENTIAL OUTPUT VOLTAGE SWING (Vp-p)
100 1000
-90
-70
-80
-60
-50
-40
-20
-30
-10
0
0.1 1 10
POWER-SUPPLY REJECTION
vs. FREQUENCY
MAX4447 TOC34
FREQUENCY (MHz)
PSR (dB)
MAX4447 TOC35
EN
VEN =
0.8V TO 2V
OUTPUT
VOLTAGE
1V/div
SHUTDOWN RESPONSE TIME
(50ns/div)
-3
-2
-1
0
1
2
3
4
-40 -15 10 35 60 85
OFFSET VOLTAGE
vs. TEMPERATURE
MAX4447 TOC36
TEMPERATURE (°C)
VOS (mV)
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ωbetween OUT+ and OUT-, AV= +2V/V for MAX4447/MAX4448,
AV= +5V/V for MAX4449, TA= +25°C, unless otherwise noted.)
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
_______________________________________________________________________________________ 9
0
10
20
30
40
50
-40 -15 10 35 60 85
QUIESCENT CURRENT
vs. TEMPERATURE
MAX4447 TOC37
TEMPERATURE (°C)
QUIESCENT CURRENT (mA)
EN = VCC
EN = GND
0
3
6
9
12
-40 -15 10 35 60 85
INPUT BIAS CURRENT
vs. TEMPERATURE
MAX4447 TOC38
TEMPERATURE (°C)
INPUT BIAS CURRENT (µA)
Pin Description
Typical Operating Characteristics (continued)
(VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ωbetween OUT+ and OUT-, AV= +2V/V for MAX4447/MAX4448,
AV= +5V/V for MAX4449, TA= +25°C, unless otherwise noted.)
1, 2 Positive Power Supply. Bypass with a 0.1µF capacitor to GND.
FUNCTION
MAX4447 MAX4448
MAX4449
PIN
1, 2
NAME
VCC
3, 6 N.C.3, 4, 6 No Connection. Not internally connected. Connect to GND for best AC perfor-
mance.
5IN5Amplifier Noninverting Input
4RG—Gain-Set Resistor. Connect gain-setting resistor from RG to GND.
9EN9Active-High, TTL-Compatible, Enable Input. Connect to VCC for normal operation.
Connect to GND for low-power operation.
15 OUT-
7, 8, 11, 12,
13, 14
15 Negative Polarity Output
10 OUT+10 Positive Polarity Output
VEE
7, 8, 11, 12,
13, 14 Negative Power-Supply Input. Bypass with a 0.1µF capacitor to GND.
16 GND16 Ground
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
10 ______________________________________________________________________________________
Detailed Description
The MAX4447/MAX4448/MAX4449 single-ended-to-dif-
ferential converters are capable of transmitting high-
speed 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-sig-
nal bandwidths of 430MHz, 330MHz, and 400MHz,
respectively. Internally trimmed resistors minimize gain
errors to under 2% over the full output range. Other fea-
tures include a high slew rate up to 6500V/µs and high
output current (130mA), which allow these amplifiers to
be used in numerous high-speed communications
applications.
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 0.1µF. 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.
Output Short-Circuit Protection
Output short-circuit protection typically limits the cur-
rent 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 signifi-
cantly higher and cause damage to the device.
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.
MAX4448
MAX4449
VEE
VCC
RGAIN
RG
IN
OUT+
AVCL = 2 ( 1 + )
OUT-
300
RGAIN
INPUT
Figure 1. Setting the Amplifier Gain
MAX4447
MAX4448
MAX4449
RGAIN
RG
IN OUT+
CLOAD
RISO
RISO
OUT- CLOAD
VCC
VEE
INPUT
Figure 2. Using an Isolation Resistor for High Capacitive Loads
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 ≤200Ω.
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 isola-
tion resistor at the output helps reduce the ringing but
slightly increases gain error.
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.
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
______________________________________________________________________________________ 11
IN
500mV/div
OUT
1V/div
CL = 15pF
IN
500mV/div
OUT
1V/div
CL = 15pF
Figure 3. Capacitive-Loaded Output Step Response Without
Isolation Resistor
Figure 4. Capacitive-Loaded Output Step Response with 14Ω
Isolation Resistor
Chip Information
TRANSISTOR COUNT: 291
MAX4447/MAX4448/MAX4449
6500V/µs, Wideband, High-Output-Current, Single-
Ended-to-Differential Line Drivers with Enable
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
© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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
© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
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
© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.
Package Information
SOICN.EPS
