19-4754; Rev 0; 12/97 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable ____________________________Features The MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 are precision, closed-loop, gain of +2 (or -1) buffers featuring high slew rates, high output current drive, and low differential gain and phase error. They operate with a single +3.15V to +11V supply or with ±1.575V to ±5.5V dual supplies. The input common-mode voltage range extends 100mV beyond the negative power-supply rail, and the output swings Rail-to-Rail®. These devices require only 5.5mA of quiescent supply current while achieving a 230MHz -3dB bandwidth and a 600V/µs slew rate. In addition, the MAX4215/ MAX4219 have a disable feature that reduces the supply current to 400µA per buffer. Input voltage noise is only 10nV/√Hz, and input current noise is only 1.3pA/√Hz. This buffer family is ideal for low-power/lowvoltage applications requiring wide bandwidth, such as video, communications, and instrumentation systems. For space-sensitive applications, the MAX4214 comes in a miniature 5-pin SOT23 package. ♦ Internal Precision Resistors for Closed-Loop Gains of +2V/V or -1V/V _______________Ordering Information ♦ Space-Saving SOT23-5, µMAX, or QSOP Packages TEMP. RANGE PINPACKAGE SOT TOP MARK MAX4214EUK-T -40°C to +85°C 5 SOT23-5 ABAH MAX4215ESA MAX4215EUA MAX4217ESA MAX4217EUA MAX4219ESD MAX4219EEE MAX4222ESD MAX4222EEE 8 SO 8 µMAX 8 SO 8 µMAX 14 SO 16 QSOP 14 SO 16 QSOP PART -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C — — — — — — — — ________________________Applications Battery-Powered Instruments Video Line Driver Analog-to-Digital Converter Interface CCD Imaging Systems Video Routing and Switching Systems Video Multiplexing Applications ♦ High Speed: 230MHz -3dB Bandwidth 90MHz 0.1dB Gain Flatness (MAX4219/22) 600V/µs Slew Rate ♦ Single 3.3V/5.0V Operation ♦ Outputs Swing Rail-to-Rail ♦ Input Common-Mode Range Extends Beyond VEE ♦ Low Differential Gain/Phase Error: 0.03%/0.04° ♦ Low Distortion at 5MHz: -72dBc SFDR -71dB Total Harmonic Distortion ♦ High Output Drive: ±120mA ♦ Low 5.5mA Supply Current ♦ 400µA Shutdown Supply Current (MAX4215/19) ______________________Selector Guide PART NO. OF AMPS MAX4214 1 No 5 SOT23 MAX4215 1 Yes 8 SO/µMAX MAX4217 2 No 8 SO/µMAX MAX4219 3 Yes 14 SO, 16 QSOP MAX4222 4 No 14 SO, 16 QSOP ENABLE __________________Pin Configurations TOP VIEW OUT 1 VEE 2 Rail-to-Rail is a registered trademark of Nippon Motorola, Inc. 5 VCC 4 IN- MAX4214 IN+ 3 Typical Application Circuit appears at end of data sheet. PIN-PACKAGE SOT23-5 Pin Configurations continued at end of data sheet. ________________________________________________________________ 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 408-737-7600 ext. 3468. MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 _________________General Description MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE) ..................................................12V IN_-, IN_+, OUT_, EN_ ....................(VEE - 0.3V) to (VCC + 0.3V) Output Short-Circuit Duration to VCC or VEE ..............Continuous Continuous Power Dissipation (TA = +70°C) 5-pin SOT23 (derate 7.1mW/°C above +70°C).............571mW 8-pin SO (derate 5.9mW/°C above +70°C)...................471mW 8-pin µMAX (derate 4.1mW/°C above +70°C) .............330mW 14-pin SO (derate 8.3mW/°C above +70°C)................667mW 16-pin QSOP (derate 8.3mW/°C above +70°C)...........667mW 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 = 0V, IN_- = 0V, EN_ = 5V, RL = ∞ to 0V, VOUT = VCC/2, noninverting configuration, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL Operating Supply Voltage Range VCC to VEE, guaranteed by PSRR tests Input Voltage Range VIN Input Offset Voltage VOS Input Offset Voltage Drift MIN VCC - 2.25 VCC + 0.1 RL = 50Ω SO, QSOP 4 10 SOT23-5, µMAX 4 15 IN_+ 1 mV 5.4 RL ≥ 50Ω, (VEE + 0.5V) ≤ VOUT ≤ (VCC - 2.0V) 1.9 2 VCC = 5V, VEE = 0V, VOUT = 2.0V 55 58 VCC = 5V, VEE = -5V, VOUT = 0V 60 66 2.1 V/V dB ROUT f = DC 25 mΩ IOUT RL = 20Ω to VCC or VEE ±120 mA ±150 mA ISC VOUT ±100 Sinking or sourcing RL = 150Ω VCC - VOH 1.60 1.90 VOL - VEE 0.04 0.075 VCC - VOH 0.75 1.00 VOL - VEE 0.04 0.075 VCC - VOH 0.06 VOL - VEE 0.06 ROUT(OFF) MAX4215/MAX4219, EN_ = 0V, 0V ≤ VOUT ≤ 5V EN_ Logic Low Threshold VIL MAX4215/MAX4219 EN_ Logic High Threshold VIH MAX4215/MAX4219 2 µA MΩ 45 RL = 2kΩ Disabled Output Resistance 12 3 VCC = 3.3V, VEE = 0V, VOUT = 0.90V RL = 50Ω Output Voltage Swing mV µV/°C AV Short-Circuit Output Current V 8 Voltage Gain Output Current V VEE - 0.1 IN_+, over input voltage range Output Resistance 11.0 VEE - 0.1 RIN PSRR UNITS IN_- Input Resistance Power-Supply Rejection Ratio (Note 2) MAX IN_+ Between any two channels for MAX4217/MAX4219/MAX4222 IB TYP 3.15 TCVOS Input Offset Voltage Matching Input Bias Current CONDITIONS 1 V kΩ VCC - 2.6 VCC - 1.6 _______________________________________________________________________________________ V V High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable (VCC = +5V, VEE = 0V, IN_- = 0V, EN_ = 5V, RL = ∞ to 0V, VOUT = VCC/2, noninverting configuration, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL EN_ Logic Input Low Current IIL EN_ Logic Input High Current IIH Quiescent Supply Current (per Buffer) ICC Shutdown Supply Current ISD CONDITIONS MIN TYP MAX UNITS MAX4215/MAX4219, (VEE + 0.2V) ≤ EN_ ≤ VCC 0.5 MAX4215/MAX4219, EN_ = VEE 200 350 MAX4215/MAX4219, EN_ = VCC 0.5 10 µA 5.5 7.0 mA 400 550 µA MAX4215/MAX4219, disabled (EN_ = VEE) µA Note 1: The MAX421_EU_ is 100% production tested at TA = +25°C. Specifications over temperature limits are guaranteed by design. Note 2: PSR for single +5V supply tested with VEE = 0V, VCC = +4.5V to +5.5V; for dual ±5V supply with VEE = -4.5V to -5.5V, VCC = +4.5V to +5.5V; and for single +3V supply with VEE = 0V, VCC = +3.15V to +3.45V. AC ELECTRICAL CHARACTERISTICS (VCC = +5V, VEE = 0V, IN_- = 0V, EN_ = 5V, RL = 100Ω to VCC/2, noninverting configuration, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Small-Signal -3dB Bandwidth SYMBOL BW-3dB Full-Power -3dB Bandwidth FPBW Bandwidth for 0.1dB Gain Flatness Slew Rate Settling Time to 0.1% BW0.1dB CONDITIONS MIN TYP VOUT = 100mVp-p MAX4214/MAX4215/MAX4217 230 MAX4219/MAX4222 200 VOUT = 2Vp-p MAX4214/MAX4215/MAX4217 220 MAX4219/MAX4222 200 VOUT = 100mVp-p MAX4214/MAX4215/MAX4217 50 MAX4219/MAX4222 90 MAX UNITS MHz MHz MHz SR VOUT = 2V step 600 V/µs tS VOUT = 2V step 45 ns Rise/Fall Time tR, tF VOUT = 100mVp-p 1 ns Spurious-Free Dynamic Range SFDR fC = 5MHz, VOUT = 2Vp-p -72 dBc Harmonic Distortion Third-Order Intercept HD IP3 Input 1dB Compression Point VOUT = 2Vp-p, fC = 5MHz Second harmonic -72 Third harmonic -77 Total harmonic distortion -71 dBc f = 10MHz 35 dBm f = 10MHz 11 dBm Differential Phase Error DP NTSC, RL = 150Ω 0.04 degrees Differential Gain Error DG NTSC, RL = 150Ω 0.03 % Input Noise-Voltage Density en f = 10kHz 10 nV/√Hz Input Noise-Current Density in f = 10kHz 1.3 pA/√Hz Input Capacitance CIN 1 pF 2 pF Disabled Output Capacitance COUT(OFF) MAX4215/MAX4219, EN_ = 0V _______________________________________________________________________________________ 3 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 DC ELECTRICAL CHARACTERISTICS (continued) AC ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, VEE = 0V, IN_- = 0V, EN_ = 5V, RL = 100Ω to VCC/2, noninverting configuration, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL Output Impedance CONDITIONS ZOUT MIN TYP MAX UNITS f = 10MHz 200 mΩ Buffer Enable Time tON MAX4215/MAX4219 100 ns Buffer Disable Time tOFF MAX4215/MAX4219 1 µs MAX4217/MAX4219/MAX4222, f = 10MHz, VOUT = 100mVp-p 0.1 dB MAX4217/MAX4219/MAX4222, f = 10MHz, VOUT = 2Vp-p -95 dB Buffer Gain Matching All-Hostile Crosstalk XTALK Note 2: PSR for single +5V supply tested with VEE = 0V, VCC = +4.5V to +5.5V; for dual ±5V supply with VEE = -4.5V to -5.5V, VCC = +4.5V to +5.5V; and for single +3V supply with VEE = 0V, VCC = +3.15V to +3.45V. __________________________________________Typical Operating Characteristics (VCC = +5V, VEE = 0V, AVCL = +2V/V, RL = 100Ω to VCC/2, TA = +25°C, unless otherwise noted.) MAX4214/MAX4215/MAX4217 GAIN FLATNESS vs. FREQUENCY VOUT = 100mVp-p VOUT = 100mVp-p 10 9 6.2 7 6 6.1 6 5 GAIN (dB) 8 7 GAIN (dB) 8 6.3 6.0 5.9 3 5.8 3 2 5.7 2 1 5.6 1 0 5.5 1M 10M FREQUENCY (Hz) 100M 1G 100k 1M 10M FREQUENCY (Hz) 100M 1G VOUT = 2Vp-p 5 4 100k 4 6.4 MAX4214-B 9 6.5 MAX4214-A 10 MAX4214/MAX4215/MAX4217 LARGE-SIGNAL GAIN vs. FREQUENCY MAX4214-C MAX4214/MAX4215/MAX4217 SMALL-SIGNAL GAIN vs. FREQUENCY GAIN (dB) MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 4 0 100k 1M 10M FREQUENCY (Hz) _______________________________________________________________________________________ 100M 1G High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable MAX4219/MAX4222 GAIN FLATNESS vs. FREQUENCY 8 6.2 7 6 6.1 6 GAIN (dB) 6.3 7 5 6.0 5.9 3 5.8 3 2 5.7 2 1 5.6 1 0 5.5 100M 1M 1G 100k -40 -50 -60 2ND HARMONIC 3RD HARMONIC -20 -30 -40 -50 -60 2ND HARMONIC -70 -80 3RD HARMONIC -90 -90 10M 0 100 200 300 400 500 600 700 800 900 MAX4214 i -20 -30 -40 -50 -60 2ND HARMONIC -70 -80 3RD HARMONIC -100 1k 0.5 RESISTIVE LOAD (Ω) FREQUENCY (Hz) VOLTAGE-NOISE DENSITY vs. FREQUENCY 1.0 1.5 2.0 2.5 3.0 3.5 VOLTAGE SWING (Vp-p) MAX4217/MAX4219/MAX4222 CROSSTALK vs. FREQUENCY CURRENT-NOISE DENSITY vs. FREQUENCY MAX4214-12 f = 5MHz -90 100M 100 1G 0 -10 -100 -100 100M 50 10 MAX4214-04 -30 1M 10M HARMONIC DISTORTION vs. VOLTAGE SWING VOUT = 2Vp-p f = 5MHz -10 HARMONIC DISTORTION (dBc) -20 100k 1M FREQUENCY (Hz) 0 MAX4214-G VOUT = 2Vp-p -80 100M HARMONIC DISTORTION vs. RESISTIVE LOAD 0 -70 10M FREQUENCY (Hz) HARMONIC DISTORTION vs. FREQUENCY -10 4 0 100k 1G HARMONIC DISTORTION (dBc) 10M MAX4214-H 1M FREQUENCY (Hz) HARMONIC DISTORTION (dBc) 5 4 100k VOUT = 2Vp-p RL = 100Ω 9 8 GAIN (dB) GAIN (dB) VOUT = 100mVp-p 6.4 10 MAX4214-E VOUT = 100mVp-p 9 6.5 MAX4214-D 10 MAX4219/MAX4222 LARGE-SIGNAL GAIN vs. FREQUENCY MAX4214-F MAX4219/MAX4222 SMALL-SIGNAL GAIN vs. FREQUENCY 30 CROSSTALK (dB) NOISE (pA/ √Hz) NOISE (nV/√Hz) 10 10 -10 -30 -50 -70 -90 -110 -130 1 1 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M -150 1 1 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 100k 1M 10M 100M 1G FREQUENCY (Hz) _______________________________________________________________________________________ 5 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 _____________________________Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, AVCL = +2V/V, RL = 100Ω to VCC/2, TA = +25°C, unless otherwise noted.) _____________________________Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, AVCL = +2V/V, RL = 100Ω to VCC/2, TA = +25°C, unless otherwise noted.) POWER-SUPPLY REJECTION vs. FREQUENCY MAX4215/MAX4219 OFF ISOLATION vs. FREQUENCY -10 -30 -40 -50 -60 10 -20 IMPEDANCE (Ω) OFF ISOLATION (dB) -20 -30 -40 -50 1 -60 0.1 -70 -80 -90 1M 10M 100M 0.01 100k 1M FREQUENCY (Hz) -0.01 100 0 IRE 0.02 0.00 -0.02 -0.06 250 200 150 100 50 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.0 100 200 300 400 LOAD RESISTANCE (Ω) 500 25 LARGE-SIGNAL PULSE RESPONSE 50 75 100 125 150 175 200 225 250 LOAD RESISTANCE (Ω) ENABLE RESPONSE TIME MAX4214-T MAX4214-S MAX4214-U 5.0V (ENABLE) IN IN EN_ 500mV/div 0V (DISABLE) OUT OUT 1G 1.5 0 SMALL-SIGNAL PULSE RESPONSE 100M OUTPUT SWING vs. LOAD RESISTANCE 300 IRE 10M CLOSED-LOOP BANDWIDTH vs. LOAD RESISTANCE VOUT = 100mVp-p 100 1M FREQUENCY (Hz) 0 0 100k FREQUENCY (Hz) 350 RL = 150Ω VCM = 1.35V -0.04 100M OUTPUT SWING (Vp-p) RL = 150Ω VCM = 1.35V CLOSED-LOOP BANDWIDTH (MHz) 0.04 0.03 0.02 0.01 0.00 MAX4214-P DIFFERENTIAL GAIN AND PHASE 10M MAX4214-24-Q 100k MAX4214-R -70 -80 DIFF. GAIN (%) 100 MAX4214-O 0 0 -10 DIFF. PHASE (deg) CLOSED-LOOP OUTPUT IMPEDANCE vs. FREQUENCY MAX4214-N 10 POWER-SUPPLY REJECTION (dB) 10 MAX4214-M 20 25mV/div MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 1V OUT 0V 20ns/div VCM = 1.25V, RL = 100Ω to GROUND 6 20ns/div VCM = 0.9V, RL = 100Ω to GROUND 1µs/div VIN = 0.5V _______________________________________________________________________________________ High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable LARGE-SIGNAL PULSE RESPONSE (CL = 5pF) MAX4214-V VOLTAGE SWING vs. TEMPERATURE MAX4214-W 5.0 MAX4214-X SMALL-SIGNAL PULSE RESPONSE (CL = 5pF) RL = 150Ω to 0V IN VOLTAGE SWING (Vp-p) 4.8 25mV/div 500mV/div IN OUT OUT 4.6 4.4 4.2 4.0 20ns/div 20ns/div VCM = 1.25V, RL = 100Ω to 0V INPUT BIAS CURRENT vs. TEMPERATURE 3 2 1 0 MAX4214-Z 5.5 5.0 4.5 75 100 -50 -25 0 25 50 TEMPERATURE (°C) 75 POWER-SUPPLY CURRENT (PER AMPLIFIER) vs. POWER-SUPPLY VOLTAGE 0.12 0.08 0.04 6 4 2 0 -50 -25 0 25 50 TEMPERATURE (°C) 7 POWER-SUPPLY CURRENT (mA) 8 100 75 100 POWER-SUPPLY CURRENT (PER AMPLIFIER) vs. TEMPERATURE MAX4214-BB 10 POWER-SUPPLY CURRENT (mA) 0.16 MAX4214-CC 0 25 50 TEMPERATURE (°C) 100 0 4.0 -25 75 0.20 INPUT OFFSET CURRENT (µA) INPUT BIAS CURRENT (µA) 4 0 25 50 TEMPERATURE (°C) INPUT OFFSET CURRENT vs. TEMPERATURE 6.0 MAX4214-Y 5 -50 -25 MAX4214-AA INPUT OFFSET VOLTAGE vs. TEMPERATURE INPUT OFFSET VOLTAGE (mV) -50 VCM = 1.75V, RL = 100Ω to 0V 6 5 4 3 3 4 5 6 7 8 9 10 POWER-SUPPLY VOLTAGE (V) 11 -50 -25 0 25 50 TEMPERATURE (°C) 75 100 _______________________________________________________________________________________ 7 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 _____________________________Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0V, AVCL = +2V/V, RL = 100Ω to VCC/2, TA = +25°C, unless otherwise noted.) MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable _______________________________________________________________Pin Description PIN 8 NAME FUNCTION 8, 9 N.C. No Connect. Not internally connected. Tie to ground or leave open. — — OUT Amplifier Output 13 11 13 VEE Negative Power Supply or Ground (in single-supply operation) — — — — IN+ Noninverting Input — — — — — IN- Inverting Input 8 4 4 4 4 VCC Positive Power Supply 8 — — — — — EN Enable Amplifier — — 1 1 — — ENA Enable Amplifier A — — 3 3 — — ENB Enable Amplifier B — — — 2 2 — — ENC Enable Amplifier C — — 1 7 7 1 1 OUTA Amplifier A Output — — 2 6 6 2 2 INA- Amplifier A Inverting Input — — 3 5 5 3 3 INA+ Amplifier A Noninverting Input — — 7 8 10 7 7 OUTB Amplifier B Output — — 6 9 11 6 6 INB- Amplifier B Inverting Input — — 5 10 12 5 5 INB+ Amplifier B Noninverting Input — — — 14 16 8 10 OUTC Amplifier C Output — — — 13 15 9 11 INC- Amplifier C Inverting Input — — — 12 14 10 12 INC+ Amplifier C Noninverting Input — — — — — 14 16 OUTD Amplifier D Output — — — — — 13 15 IND- Amplifier D Inverting Input — — — — — 12 14 IND+ Amplifier D Noninverting Input MAX4214 MAX4215 MAX4217 SOT23-5 SO/µMAX SO/µMAX SO MAX4219 QSOP SO MAX4222 QSOP — 1, 5 — — 8, 9 — 1 6 — — — 2 4 4 11 3 3 — 4 2 5 7 — — — _______________________________________________________________________________________ High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable The MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 are single-supply, rail-to-rail output, voltage-feedback, closed-loop buffers that employ current-feedback techniques to achieve 600V/µs slew rates and 230MHz bandwidths. These buffers use internal 500Ω resistors to provide a preset closed-loop gain of +2V/V in the noninverting configuration or -1V/V in the inverting configuration. Excellent harmonic distortion and differential gain/phase performance make them an ideal choice for a wide variety of video and RF signal-processing applications. Local feedback around the buffer’s output stage ensures low output impedance, which reduces gain sensitivity to load variations. This feedback also produces demand-driven current bias to the output transistors for ±120mA drive capability, while constraining total supply current to less than 7mA. Since the inverting input exhibits a 500Ω input impedance, terminate the input with a 56Ω resistor when configured for an inverting gain in 50Ω applications (terminate with 88Ω in 75Ω applications). Terminate the input with a 49.9Ω resistor in the noninverting case. Output terminating resistors should directly match cable impedances in either configuration. Layout Techniques Maxim recommends using microstrip and stripline techniques to obtain full bandwidth. To ensure the PC board does not degrade the buffer’s performance, design it for a frequency greater than 1GHz. Pay careful attention to inputs and outputs to avoid large parasitic capacitance. Whether or not you use a constantimpedance board, observe the following guidelines when designing the board: • Don’t use wire-wrapped boards. They are too inductive. ___________Applications Information • Don’t use IC sockets. They increase parasitic capacitance and inductance. Power Supplies • Use surface-mount instead of through-hole components for better high-frequency performance. These devices operate from a single +3.15V to +11V power supply or from dual supplies of ±1.575V to ±5.5V. For single-supply operation, bypass the VCC pin to ground with a 0.1µF capacitor as close to the pin as possible. If operating with dual supplies, bypass each supply with a 0.1µF capacitor. • Use a PC board with at least two layers; it should be as free from voids as possible. • Keep signal lines as short and as straight as possible. Do not make 90° turns; round all corners. Selecting Gain Configuration Input Voltage Range and Output Swing Each buffer in the MAX4214 family can be configured for a voltage gain of +2V/V or -1V/V. For a gain of +2V/V, ground the inverting terminal. Use the noninverting terminal as the signal input of the buffer (Figure 1a). Grounding the noninverting terminal and using the inverting terminal as the signal input configures the buffer for a gain of -1V/V (Figure 1b). The MAX4214 family’s input range extends from (VEE - 100mV) to (VCC - 2.25V). Input ground sensing increases the dynamic range for single-supply applications. The outputs drive a 2kΩ load to within 60mV of the power-supply rails. With smaller resistive loads, the output swing is reduced as shown in the Electrical Characteristics and Typical Operating Characteristics. IN+ IN IN+ OUT RTIN RTO OUT OUT RS RTO RO OUT RO 500Ω 500Ω 500Ω IN IN- 500Ω IN- RTIN MAX42_ _ Figure 1a. Noninverting Gain Configuration (AV = +2V/V) MAX42_ _ Figure 1b. Inverting Gain Configuration (AV = -1V/V) _______________________________________________________________________________________ 9 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 ________________ Detailed Description As the load resistance decreases, the useful input range is effectively limited by the output drive capability, since the buffers have a fixed voltage gain of +2V/V or -1V/V. For example, a 50Ω load can typically be driven from 40mV above VEE to 1.6V below VCC, or 40mV to 3.4V when operating from a single +5V supply. If the buffer is operated in the noninverting, gain of +2V/V configuration with the inverting input grounded, the useful input voltage range becomes 20mV to 1.7V instead of the -100mV to 2.75V indicated by the Electrical Charac teristics. Beyond the useful input range, the buffer output is a nonlinear function of the input, but it will not undergo phase reversal or latchup. Enable sists of five back-to-back Schottky diodes between IN_+ and IN_-. These diodes reduce the disabled output resistance from 1kΩ to 500Ω when the output voltage is 3V greater or less than the voltage at IN_+. Under these conditions, the input protection diodes will be forward biased, lowering the disabled output resistance to 500Ω. Output Capacitive Loading and Stability The MAX4214 family provides maximum AC performance with no load capacitance. This is the case when the load is a properly terminated transmission line. These devices are designed to drive up to 20pF of load capacitance without oscillating, but AC performance will be reduced under these conditions. The MAX4215 and MAX4219 have an enable feature (EN_) that allows the buffer to be placed in a low-power state. When the buffers are disabled, the supply current is reduced to 400µA per buffer. ENABLE As the voltage at the EN_ pin approaches the negative supply rail, the EN_ input current rises. Figure 2 shows a graph of EN_ input current versus EN_ pin voltage. Figure 3 shows the addition of an optional resistor in series with the EN pin, to limit the magnitude of the current increase. Figure 4 displays the resulting EN pin input current to voltage relationship. 10k EN_ IN+ OUT MAX42_ _ Disabled Output Resistance The MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 include internal protection circuitry that prevents damage to the precision input stage from large differential input voltages (Figure 5). This protection circuitry con- IN500Ω 0 -1 -20 -2 INPUT CURRENT (µA) 0 -40 -60 -80 -100 -3 -4 -5 -6 -7 -120 -8 -140 -9 -10 -160 0 100 200 300 400 500 VIL (mV ABOVE VEE) Figure 2. Enable Logic-Low Input Current vs. Enable LogicLow Threshold 10 500Ω Figure 3. Circuit to Reduce Enable Logic-Low Input Current 20 INPUT CURRENT (µA) MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 0 100 200 300 400 500 VIL (mV ABOVE VEE) Figure 4. Enable Logic-Low Input Current vs. Enable LogicLow Threshold with 10kΩ Series Resistor ______________________________________________________________________________________ High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 5 MAX4214 MAX4215 MAX4217 MAX4219 MAX4222 OUT NORMALIZED GAIN (dB) IN+ CL = 15pF 4 3 CL = 10pF 2 1 0 CL = 5pF -1 -2 -3 IN500Ω -4 500Ω 100k 1M 10M 100M 1G FREQUENCY (Hz) Figure 5. Input Protection Circuit Figure 6. Small-Signal Gain vs. Frequency with Load Capacitance and No Isolation Resistor 16 14 500Ω 12 500Ω RISO (Ω) 10 RISO MAX42_ _ VIN 8 6 VOUT 4 CL 2 RTIN 50Ω 0 0 50 100 150 CLOAD (pF) 200 250 Figure 7. Driving a Capacitive Load Through an Isolation Resistor Figure 8. Isolation Resistance vs. Capacitive Load Driving large capacitive loads increases the chance of oscillations occurring in most amplifier circuits. This is especially true for circuits with high loop gains, such as voltage followers. The buffer’s output resistance and the load capacitor combine to add a pole and excess phase to the loop response. If the frequency of this pole is low enough to interfere with the loop response and degrade phase margin sufficiently, oscillations can occur. Figure 6 shows the devices’ frequency response under different capacitive loads. To drive loads with greater than 20pF of capacitance or to settle out some of the peaking, the output requires an isolation resistor like the one shown in Figure 7. Figure 8 is a graph of the optimal isolation resistor versus load capacitance. Figure 9 shows the frequency response of the MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 when driving capacitive loads with a 27Ω isolation resistor. A second problem when driving capacitive loads results from the amplifier’s output impedance, which looks inductive at high frequencies. This inductance forms an L-C resonant circuit with the capacitive load, which causes peaking in the frequency response and degrades the amplifier’s gain margin. Coaxial cables and other transmission lines are easily driven when properly terminated at both ends with their characteristic impedance. Driving back-terminated transmission lines essentially eliminates the lines’ capacitance. ______________________________________________________________________________________ 11 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 6 3 2 _________Typical Application Circuit RISO = 27Ω CL = 47pF 1 NORMALIZED GAIN (dB) MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 0 IN+ 75Ω CL = 68pF -1 -2 VOUT CL = 120pF -3 75Ω MAX4214 -4 IN- -5 500Ω 500Ω -6 -7 100k 1M 10M 100M 1G GAIN OF +2 VIDEO/RF CABLE DRIVER FREQUENCY (Hz) Figure 9. Small-Signal Gain vs. Frequency with Load Capacitance and 27Ω Isolation Resistor ____________________Chip Information PART NO. OF TRANSISTORS MAX4214 95 MAX4215 95 MAX4217 190 MAX4219 299 MAX4222 362 SUBSTRATE CONNECTED TO VEE 12 ______________________________________________________________________________________ High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable TOP VIEW N.C. 1 IN- 2 8 EN OUTA 1 7 VCC INA- 2 MAX4215 8 VCC 7 OUTB MAX4217 IN+ 3 6 OUT INA+ 3 6 INB- VEE 4 5 N.C. VEE 4 5 INB+ SO/µMAX SO/µMAX ENA 1 14 OUTC ENA 1 16 OUTC ENC 2 13 INC- ENC 2 15 INC- ENB 3 12 INC+ ENB 3 14 INC+ MAX4219 MAX4219 11 VEE VCC 4 INA+ 5 10 INB+ INA+ 5 12 INB+ INA- 6 9 INB- INA- 6 11 INB- OUTA 7 8 OUTB OUTA 7 10 OUTB VCC 4 N.C. 8 13 VEE 9 N.C. SO QSOP OUTA 1 14 OUTD OUTA 1 16 OUTD INA- 2 13 IND- INA- 2 15 IND- 12 IND+ INA+ 3 11 VEE VCC 4 10 INC+ INB+ 5 12 INC+ INA+ 3 VCC 4 MAX4222 INB+ 5 14 IND+ MAX4222 13 VEE INB- 6 9 INC- INB- 6 11 INC- OUTB 7 8 OUTC OUTB 7 10 OUTC N.C. 8 9 N.C. SO QSOP ______________________________________________________________________________________ 13 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 _______________________________________________Pin Configurations (continued) __________________________________________________Tape-and-Reel Information D P0 W P2 B0 t D1 F P NOTE: DIMENSIONS ARE IN MM. AND FOLLOW EIA481-1 STANDARD. K0 A0 P0 3.988 ±0.102 A0 3.200 ±0.102 E 1.753 ±0.102 B0 3.099 ±0.102 F 3.505 ±0.051 P010 40.005 ±0.203 D 1.499 +0.102 +0.000 K0 1.397 ±0.102 P2 2.007 ±0.051 3.988 ±0.102 t 0.254 ±0.127 0.991 +0.254 +0.000 P D1 W 8.001 +0.305 -0.102 5 SOT23-5 E ________________________________________________________Package Information SOT5L.EPS MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 14 ______________________________________________________________________________________ High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers with Enable 8LUMAXD.EPS SOICN.EPS ______________________________________________________________________________________ 15 MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 ___________________________________________Package Information (continued) ___________________________________________Package Information (continued) QSOP.EPS MAX4214/MAX4215/MAX4217/MAX4219/MAX4222 High-Speed, Single-Supply, Gain of +2, Closed-Loop, Rail-to-Rail Buffers 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1997 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.