19-1519 Rev 0; 8/99 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable Features ♦ 6500V/µs Slew Rate (MAX4449) The MAX4447/MAX4448/MAX4449 can deliver differential output swings of ±6.2V from ±5V supplies with a 50Ω 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. ♦ -78dB SFDR at 100kHz ♦ 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) ♦ Low Differential Gain/Phase: 0.01%/0.02° ♦ Ultra-Low Noise: 23nV/√Hz at fIN = 1MHz ♦ 8ns Settling Time to 0.1% Ordering Information Applications Differential Line Driver Single-Ended-to-Differential Conversion High-Speed Differential Transmitter Coaxial to Twisted-Pair Converter PART MAX4447ESE MAX4448ESE MAX4449ESE TEMP. RANGE PIN-PACKAGE -40°C to +85°C -40°C to +85°C -40°C to +85°C 16 Narrow SO 16 Narrow SO 16 Narrow SO Differential Pulse Amplifier Differential ADC Driver Typical Operating Circuit xDSL Applications Video and RF Signal Processing and Transmission +5V Pin Configuration 0.1µF TOP VIEW VCC 1 16 GND VCC 2 15 OUT- N.C. 3 14 VEE N.C. (RG) 4 IN 5 MAX4447 MAX4448 MAX4449 N.C. 6 13 VEE 12 VEE 11 VEE VEE 7 10 OUT+ VEE 8 9 SO 75Ω 75Ω VCC IN INPUT 75Ω EN MAX4447 VEE GND OUT+ RT TO LOAD OUT- RT 75Ω 0.1µF EN -5V ( ) ARE FOR MAX4448/MAX4449 ONLY ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 1-800-835-8769. MAX4447/MAX4448/MAX4449 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/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 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. MAX4447/MAX4448/MAX4449 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable 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 = +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, 10sec) .............................+300°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. 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.) PARAMETER CONDITIONS MIN VCC VCC guaranteed by PSRR test 4.5 5.5 VEE VEE guaranteed by PSRR test -5.5 -4.5 Input Voltage Range VIN Guaranteed by gain-error test -6/AV Input Offset Voltage VOS VIN = 0 1.3 TCVOS VIN = 0 25 IB VIN = 0 7 Operating Supply Voltage Range Input Offset Voltage Temperature Coefficient Input Bias Current Input Resistance SYMBOL RIN TYP -3.0V ≤ VIN ≤ 3.0V AV Gain Drift Output Voltage Swing VOUT 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 IOUT ISC PSRR 2 MAX4448/MAX4449 (Note 1) MAX4447 MAX4448/MAX4449 MAX4447 VOUT = 0 MAX4448/MAX4449 RL = 100Ω between OUT+ and OUTRL = 50Ω between OUT+ and OUTRL = 20Ω between OUT+ and OUTShort circuit to GND VS = ±4.5V to ±5.5V VEN = 0, VOUT+ = VOUT- = 3.15V or -3.15V IOUT(OFF) VIL VIH IIL IIH IQ V 50 mV µV/°C 45 µA kΩ V/V 2 · (1+300/RG) ±6.3 ±5.2 90 53 0.1 -0.3 -0.002 0.01 ±7.4 ±6.2 130 140 75 4 2 5 -2.5 0.8 46 3.2 _______________________________________________________________________________________ % %/°C V 30 0.8 2 VEN = 0 VEN = 5V VIN = 0, VEN ≥ VIH VIN = 0, VEN ≤ VIL V 2 -6V ≤ VOUT ≤ 6V Gain Error Quiescent Current -6V ≤ VOUT ≤ 6V UNITS +6/AV 50 MAX4447 Gain MAX 10 10 55 5.5 mA mA dB µA V V µA µA mA 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable (VCC = +5V, VEE = -5V, RL = 100Ω between OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449, VOUT = VOUT+ - VOUT-, TA = +25°C, unless otherwise noted.) PARAMETER Small-Signal -3dB Bandwidth SYMBOL BWSS CONDITIONS VOUT = 100mVp-p VOUT = 8Vp-p VOUT = 4Vp-p Large-Signal -3dB Bandwidth Large-Signal -3dB Bandwidth BWLS VOUT = 2Vp-p 0.1dB Gain Flatness VOUT = 100mVp-p VOUT = 8V step Slew Rate (Note 2) SR VOUT = 4V step VOUT = 2V step VOUT = 8V step Rise Time (Note 2) tRISE VOUT = 4V step VOUT = 2V step MIN TYP MAX4447 430 MAX4448 330 MAX4449 400 MAX4449 250 MAX4447 250 MAX4448 260 MAX4449 320 MAX4447 285 MAX4448 310 MAX4449 405 MAX4447 200 MAX4448 40 MAX4449 140 MAX4447 5700 MAX4448 4300 MAX4449 6500 MAX4447 3000 MAX4448 3000 MAX4449 3700 MAX4447 1700 MAX4448 1900 MAX4449 1800 MAX4447 670 MAX4448 1030 MAX4449 850 MAX4447 720 MAX4448 820 MAX4449 660 MAX4447 720 MAX4448 520 MAX4449 740 MAX UNITS MHz MHz MHz V/µs ps _______________________________________________________________________________________ 3 MAX4447/MAX4448/MAX4449 AC ELECTRICAL CHARACTERISTICS MAX4447/MAX4448/MAX4449 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable AC ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, VEE = -5V, RL = 100Ω between OUT+ and OUT-, AVCL = +2V/V for MAX4447/MAX4448, AVCL = +5V/V for MAX4449, VOUT = VOUT+ - VOUT-, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS VOUT = 8V step Fall Time (Note 2) tFALL VOUT = 4V step VOUT = 2V step TYP 1100 MAX4448 900 MAX4449 900 MAX4447 900 MAX4448 810 MAX4449 780 MAX4447 800 MAX4448 770 MAX4449 660 fC = 100kHz -78 fC = 5MHz -78 fC = 20MHz -62 fC = 100MHz -46 fC = 100kHz -78 fC = 5MHz -78 fC = 20MHz -62 fC = 100MHz -46 fC = 100kHz -86 fC = 5MHz -86 fC = 20MHz -71 Settling Time Spurious-Free Dynamic Range MIN MAX4447 MAX 8 SFDR 2nd Harmonic Distortion VOUT = 2Vp-p VOUT = 2Vp-p VOUT = 2Vp-p 3rd Harmonic Distortion fC = 100MHz UNITS ps ns dBc dBc dBc -54 Differential Phase Error DP NTSC, RL = 150Ω 0.02 Differential Gain Error DG NTSC, RL = 150Ω 0.01 % Input Noise Voltage Density eN f = 1MHz (Note 3) 24 nV/√Hz Input Noise Current Density iN f = 1MHz 1.8 pA/√Hz f = 10MHz, each output to ground 1.0 Ω VIN = 1V, VOUT settle to within 1% 55 ns Output Impedance ZOUT± Enable Time Disable Time degrees VIN = 1V, VOUT settle to within 1% 0.4 µs Power-Up Time tON VIN = 1V, VOUT settle to within 1% 0.08 µs Power-Down Time tOFF VIN = 1V, VOUT settle to within 1% 0.5 µs 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 _______________________________________________________________________________________ 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4448 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) 2 1 0 0 -1 -2 3 2 1 GAIN (dB) 1 -1 -2 0 -1 -2 -3 -3 -3 -4 -4 -4 -5 -5 -5 -6 -6 1M 10M 100M 1G -6 100k 1M 10M 100M 1G 100k 10M 100M FREQUENCY (Hz) FREQUENCY (Hz) MAX4447 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p) MAX4448 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p) MAX4449 GAIN FLATNESS vs. FREQUENCY (VOUT = 100mVp-p) 0.4 0.3 0.4 0.3 0.5 0.4 0.3 0.2 0.1 0.1 0.1 -0.1 GAIN (dB) 0.2 GAIN (dB) 0.2 0 0 -0.1 0 -0.1 -0.2 -0.2 -0.2 -0.3 -0.3 -0.3 -0.4 -0.4 -0.4 -0.5 -0.5 -0.5 1M 10M 100M 1G 100k 1M 10M 100M 1G MAX4447 TOC06 0.5 MAX4447 TOC04 0.5 100k 1M FREQUENCY (Hz) MAX4447 TOC05 100k 100k 1G 1M 10M 100M 1G FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) MAX4447 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p) MAX4448 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p) MAX4449 LARGE-SIGNAL GAIN vs. FREQUENCY (VOUT = 2Vp-p) 2 3 2 1 0 0 GAIN (dB) 1 -1 -2 4 3 2 1 GAIN (dB) 3 -1 -2 0 -1 -2 -3 -3 -3 -4 -4 -4 -5 -5 -5 -6 -6 100k 1M 10M FREQUENCY (Hz) 100M 1G MAX4447 TOC09 4 MAX4447 TOC07 4 MAX4447 TOC08 GAIN (dB) 3 GAIN (dB) GAIN (dB) 2 4 MAX4447 TOC02 3 GAIN (dB) 4 MAX4447 TOC01 4 MAX4449 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) MAX4447 TOC03 MAX4447 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) -6 100k 1M 10M FREQUENCY (Hz) 100M 1G 100k 1M 10M 100M 1G FREQUENCY (Hz) _______________________________________________________________________________________ 5 MAX4447/MAX4448/MAX4449 Typical Operating Characteristics (VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ω between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ω between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25°C, unless otherwise noted.) MAX4448 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) 15 20 15 CLOAD = 15pF 5 0 -5 CLOAD = 5pF 15 CLOAD = 15pF 10 GAIN (dB) 10 20 5 0 -5 CLOAD = 5pF 5 0 -5 -10 -10 -15 -15 -15 -20 -20 -20 1M 10M 100M -25 100k 1G 1M 10M 100M 1G 100k 10M 100M MAX4447 SMALL-SIGNAL PULSE RESPONSE MAX4448 SMALL-SIGNAL PULSE RESPONSE MAX4449 SMALL-SIGNAL PULSE RESPONSE INPUT 50mV/div INPUT 25mV/div OUTPUT 100mV/div OUTPUT 100mV/div OUTPUT 125mV/div (5ns/div) MAX4447 LARGE-SIGNAL PULSE RESPONSE MAX4448 LARGE-SIGNAL PULSE RESPONSE MAX4449 LARGE-SIGNAL PULSE RESPONSE MAX4447 TOC17 MAX4447 TOC18 (5ns/div) MAX4447 TOC16 (5ns/div) INPUT 500mV/div INPUT 500mV/div INPUT 200mV/div OUTPUT 1V/div OUTPUT 1V/div OUTPUT 1V/div (5ns/div) (5ns/div) 1G MAX4447 TOC15 FREQUENCY (Hz) MAX4447 TOC14 FREQUENCY (Hz) INPUT 50mV/div 6 1M FREQUENCY (Hz) MAX4447 TOC13 100k CLOAD = 5pF -10 -25 -25 CLOAD = 15pF 10 GAIN (dB) 20 25 MAX4447 TOC11 25 MAX4447 TOC10 25 MAX4449 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) MAX4447 TOC12 MAX4447 SMALL-SIGNAL GAIN vs. FREQUENCY (VOUT = 100mVp-p) GAIN (dB) MAX4447/MAX4448/MAX4449 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable (5ns/div) _______________________________________________________________________________________ 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable MAX4447 DIFFERENTIAL GAIN AND PHASE MAX4447 0.000 -0.002 -0.004 MAX4448 4000 0 100 0 2 4 6 8 10 0.03 0.02 0.01 0 -0.01 0 12 0 10 20 30 40 50 60 70 80 90 100 IRE IRE MAX4449 DIFFERENTIAL GAIN AND PHASE MAX4447 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p) MAX4448 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p) -10 0.015 0.010 0.005 0.000 -0.005 -30 -40 -50 -60 2ND -70 -10 -20 -30 DISTORTION (dB) 100 IRE DISTORTION (dB) -20 0 0 -40 -50 -70 -90 -100 -100 1M 10M IRE MAX4449 HARMONIC DISTORTION vs. FREQUENCY (VOUT = 2Vp-p) -40 -50 2ND -60 -70 MAX4447 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz) MAX4448 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz) -10 -20 DISTORTION (dB) -30 -30 -40 -50 -60 2ND -80 -80 -90 -90 1M 10M FREQUENCY (Hz) 100M -20 -30 -40 -50 -60 3RD -80 3RD 2ND -90 -100 -100 -100 0 -10 -70 -70 3RD 100M FREQUENCY (Hz) DISTORTION (dB) -20 10M FREQUENCY (Hz) MAX4447 TOC26 -10 1M 100M 0 MAX4447 TOC25 0 2ND -80 -90 10 20 30 40 50 60 70 80 90 100 3RD -60 3RD -80 MAX4447 TOC24 0 MAX4447 TOC23 0.02 0.00 -0.02 -0.04 -0.06 -0.08 0 10 20 30 40 50 60 70 80 90 100 OUTPUT VOLTAGE (V) MAX4447 TOC22 0 DIFFERENTIAL GAIN (%) 100 IRE 0.04 0.03 0.02 0.01 0 -0.01 DIFFERENTIAL PHASE (°) DIFFERENTIAL PHASE (°) 1000 DIFFERENTIAL PHASE (°) 0 IRE 3000 2000 DISTORTION (dB) 0.002 0.000 -0.002 -0.004 -0.006 MAX4447 TOC27 SLEW RATE (V/µs) 5000 0.002 MAX4447 TOC21 6000 0.004 DIFFERENTIAL GAIN (%) MAX4449 MAX4448 DIFFERENTIAL GAIN AND PHASE MAX4447 TOC20 MAX4447 TOC19 7000 DIFFERENTIAL GAIN (%) SLEW RATE vs. OUTPUT VOLTAGE 0 1 2 3 4 5 6 OUTPUT VOLTAGE SWING (V) 7 8 0 1 2 3 4 5 6 7 8 OUTPUT VOLTAGE SWING (V) _______________________________________________________________________________________ 7 MAX4447/MAX4448/MAX4449 Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ω between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ω between OUT+ and OUT-, AV = +2V/V for MAX4447/MAX4448, AV = +5V/V for MAX4449, TA = +25°C, unless otherwise noted.) MAX4449 HARMONIC DISTORTION vs. OUTPUT VOLTAGE SWING (fC = 5MHz) -40 -50 2ND 3RD -70 -80 -90 -100 2 3 4 5 6 7 1 10 100 1k 10k 100k 10 100 1k 10k 100k 1M FREQUENCY (Hz) ISOLATION RESISTANCE vs. CAPACITIVE LOAD OUTPUT IMPEDANCE vs. FREQUENCY DIFFERENTIAL OUTPUT VOLTAGE SWING vs. RESISTIVE LOAD 18 16 14 10 1 10 40 60 80 100 120 14 12 10 8 6 4 2 0 0.1 20 16 MAX4447 TOC33 MAX4447 TOC31 20 100 DIFFERENTIAL OUTPUT VOLTAGE SWING (Vp-p) FREQUENCY (Hz) 12 100k 1M 10M 100M 0 1G 40 80 120 CAPACITIVE LOAD (pF) FREQUENCY (Hz) RL (Ω) POWER-SUPPLY REJECTION vs. FREQUENCY SHUTDOWN RESPONSE TIME OFFSET VOLTAGE vs. TEMPERATURE VOS (mV) -50 OUTPUT VOLTAGE 1V/div -70 85 2 -40 -60 60 3 VEN = 0.8V TO 2V -30 200 MAX4447 TOC36 -20 EN 160 4 MAX4447 TOC35 MAX4447 TOC34 0 -10 1 0 -1 -2 -80 -3 -90 0.1 1 10 FREQUENCY (MHz) 8 1 1M OUTPUT VOLTAGE SWING (V) 22 0 MAX4447 TOC30 MAX4447 TOC29 8 CURRENT IMPEDANCE (Ω) 1 10 1 10 0 ISOLATION RESISTANCE (Ω) 100 100 CURRENT NOISE DENSITY (pA/ Hz) -30 MAX4447 TOC32 DISTORTION (dB) -20 1000 VOLTAGE NOISE DENSITY (nV/ Hz) MAX4447 TOC28 0 -60 CURRENT NOISE DENSITY vs. FREQUENCY VOLTAGE NOISE DENSITY vs. FREQUENCY -10 PSR (dB) MAX4447/MAX4448/MAX4449 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable 100 1000 (50ns/div) -40 -15 10 35 TEMPERATURE (°C) _______________________________________________________________________________________ 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable QUIESCENT CURRENT vs. TEMPERATURE 30 20 10 MAX4447 TOC38 40 12 INPUT BIAS CURRENT (µA) QUIESCENT CURRENT (mA) EN = VCC MAX4447 TOC37 50 INPUT BIAS CURRENT vs. TEMPERATURE 9 6 3 EN = GND 0 -40 -15 10 35 60 0 85 -40 TEMPERATURE (°C) -15 10 35 60 85 TEMPERATURE (°C) Pin Description PIN MAX4448 MAX4449 NAME MAX4447 FUNCTION 1, 2 1, 2 VCC Positive Power Supply. Bypass with a 0.1µF capacitor to GND. 3, 4, 6 3, 6 N.C. No Connection. Not internally connected. Connect to GND for best AC performance. — 4 RG Gain-Set Resistor. Connect gain-setting resistor from RG to GND. 5 5 IN Amplifier Noninverting Input 7, 8, 11, 12, 13, 14 7, 8, 11, 12, 13, 14 VEE Negative Power-Supply Input. Bypass with a 0.1µF capacitor to GND. 9 9 EN Active-High, TTL-Compatible, Enable Input. Connect to VCC for normal operation. Connect to GND for low-power operation. 10 10 OUT+ Positive Polarity Output 15 15 OUT- Negative Polarity Output 16 16 GND Ground _______________________________________________________________________________________ 9 MAX4447/MAX4448/MAX4449 Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, VEN = +5V, VOUT = VOUT+ - VOUT-, RL = 100Ω between 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, SingleEnded-to-Differential Line Drivers with Enable 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. VCC INPUT IN OUT+ MAX4448 MAX4449 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/µs and high output current (130mA), which allow these amplifiers to be used in numerous high-speed communications applications. RG 300 AVCL = 2 ( 1 + RGAIN ) RGAIN VEE Applications Information Grounding and Bypassing OUT- Figure 1. Setting the Amplifier Gain Use high-frequency design techniques when designing the PC board for the MAX4447/MAX4448/MAX4449: VCC • 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. INPUT IN OUT+ RISO CLOAD MAX4447 MAX4448 MAX4449 RG RISO OUT- CLOAD RGAIN 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 ______________________________________________________________________________________ 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable IN 500mV/div CL = 15pF OUT 1V/div CL = 15pF OUT 1V/div Figure 3. Capacitive-Loaded Output Step Response Without Isolation Resistor Figure 4. Capacitive-Loaded Output Step Response with 14Ω Isolation Resistor Setting Gain Twisted-Pair Line Driver 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. 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 Chip Information 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 ______________________________________________________________________________________ 11 MAX4447/MAX4448/MAX4449 IN 500mV/div 6500V/µs, Wideband, High-Output-Current, SingleEnded-to-Differential Line Drivers with Enable SOICN.EPS MAX4447/MAX4448/MAX4449 Package Information 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.