19-1552; Rev 0; 10/99 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable Features ♦ +4.5V to +8.0V Single-Supply Operation The MAX4265 single and MAX4268 dual unity-gain-stable amplifiers have up to a 300MHz gain-bandwidth product. The MAX4266 single and MAX4269 dual amplifiers have up to a 350MHz bandwidth at a minimum stable gain of +2V/V. The MAX4267 single and MAX4270 dual amplifiers have a 200MHz bandwidth at a minimum stable gain of +5V/V. For additional power savings, these amplifiers feature a low-power disable mode that reduces supply current to 1.6mA and places the outputs in a high-impedance state. The MAX4265/MAX4266/MAX4267 are available in a space-saving 8-pin µMAX package, and the MAX4268/ MAX4269/MAX4270 are available in a 16-pin QSOP package. ♦ Shutdown Mode Places Outputs in HighImpedance State ♦ Superior SFDR with 100Ω Load -90dBc (fC = 5MHz ) -60dBc (fC = 100MHz) ♦ 35dBm IP3 (fC = 20MHz) ♦ 8nV/√Hz Voltage Noise Density ♦ 100MHz 0.1dB Gain Flatness (MAX4268) ♦ 900V/µs Slew Rate ♦ ±45mA Output Driving Capability Ordering Information PART MAX4265EUA* MAX4265ESA* MAX4266EUA* MAX4266ESA* MAX4267EUA* TEMP. RANGE -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C PIN-PACKAGE 8 µMAX 8 SO 8 µMAX 8 SO -40°C to +85°C 8 µMAX MAX4267ESA* -40°C to +85°C 8 SO MAX4268EEE -40°C to +85°C 16 QSOP MAX4268ESD MAX4269EEE -40°C to +85°C 14 SO -40°C to +85°C 16 QSOP Base-Station Amplifiers MAX4269ESD -40°C to +85°C 14 SO IF Amplifiers MAX4270EEE -40°C to +85°C 16 QSOP High-Frequency ADC Drivers MAX4270ESD -40°C to +85°C 14 SO Applications *Future product—contact factory for availability. High-Speed DAC Buffers RF Telecom Applications SFDR vs. Input Frequency High-Frequency Signal Processing -30 BANDWIDTH (MHz) SFDR (dBc) PART MIN GAIN (V/V) -50 -60 MAX4265 1 1 300 -70 MAX4266 1 2 350 -80 MAX4267 1 5 200 -90 MAX4268 2 1 300 MAX4269 2 2 350 MAX4270 2 5 200 VOUT = 1Vp-p RL = 100Ω to VCC/2 -40 Selector Guide NO. OF OP AMPS MAX4268/70 toc10 -20 Pin Configurations appear at end of data sheet. -100 0.1M MAX4270 MAX4269 MAX4268 1M 10M 100M FREQUENCY (Hz) ________________________________________________________________ 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. MAX4265–MAX4270 General Description The MAX4265–MAX4270 single-supply, voltage-feedback op amps are capable of driving a 100Ω load while maintaining ultra-low distortion over a wide bandwidth. They offer superior spurious-free dynamic range (SFDR) performance: -90dBc or better at frequencies below 5MHz and -60dBc at a 100MHz frequency. Additionally, input voltage noise density is 8nV/√Hz while operating from a single +4.5V to +8.0V supply or from dual ±2.25V to ±4.0V supplies. These features make the MAX4265–MAX4270 ideal for use in high-performance communications and signalprocessing applications that require low distortion and wide bandwidth. MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE)...............................................+8.5V Voltage on Any Other Pin .................(VEE - 0.3V) to (VCC + 0.3V) Short-Circuit Duration (VOUT to VCC or VEE) ..............Continuous Continuous Power Dissipation (TA = +70°C) 16-Pin QSOP (derate 8.33mW/°C above +70°C)........667mW 8-Pin µMAX (derate 4.10mW/°C above +70°C) ..........330mW 8-Pin SO (derate 5.9mW/°C above +70°C).................471mW 14-Pin SO (derate 8.33mW/°C above +70°C).............667mW Operating Temperature Range ...........................-40°C to +85°C Storage Temperature Range .............................-65°C to +150°C Junction Temperature ......................................................+150°C Lead Temperature (soldering, 10s) .................................+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 = 0, RL = 100Ω to VCC/2, VCM = VCC/2, TA = TMIN to TMAX, typical values are at TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 8.0 V Operating Supply Voltage Range VCC Inferred from PSRR test 4.5 Common-Mode Input Voltage VCM Inferred from CMRR test VEE + 1.6 Input Offset Voltage VOS 1 TCVOS 1.5 µV/°C 1 mV Input Offset Voltage Drift Input Offset Voltage Channel Matching Input Bias Current Input Offset Current MAX4268/MAX4269/MAX4270 VCC - 1.6 9 V mV IB 3.5 40 µA IOS 0.1 5.5 µA Common-Mode Input Resistance RINCM Either input, (VEE + 1.6) ≤ VCM ≤ (VCC - 1.6) Differential Input Resistance RINDIFF -10mV ≤ VIN ≤ 10mV 40 kΩ Common-Mode Rejection Ratio CMRR (VEE + 1.6V) ≤ VCM ≤ (VCC - 1.6V), no load 60 85 dB Power-Supply Rejection Ratio PSRR VCC = 4.5V to 8.0V 60 85 dB 60 Open-Loop Voltage Gain AOL 1.75V ≤ VOUT ≤ 3.25V Output Voltage Swing VOUT VCC - VOH, VOL - VEE Output Current Drive IOUT RL = 20Ω Output Short-Circuit Current Closed-Loop Output Resistance Power-Up Time Quiescent Supply Current Disable Output Leakage Current ISC 1 Sinking or sourcing to VCC or VEE ROUT tPWRUP IS 95 1.1 ±30 VO = 1V step, 0.1% settling time MΩ dB 1.5 mA 100 mA 0.035 Ω 10 µs Normal mode, EN_ = 5V or floating 28 32 Disable mode, EN_ = 0 1.6 5 VEN_ = 0, VEE ≤ VOUT ≤ VCC 0.2 5 VCC - 3.5 EN_ Logic Low Threshold VCC - 1.5 EN_ Logic High Threshold dB ±45 mA µA V V EN_ Logic Input Low Current VEN_ = 0 5 100 µA EN_ Logic Input High Current VEN_ = 5V 1 30 µA 2 _______________________________________________________________________________________ Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable (VCC = +5V, VEE = 0, RL = 100Ω to VCC/2, VCM = VCC/2, MAX4265/MAX4268 AV = +1V/V, MAX4266/MAX4269 AV = +2V/V, MAX4267/MAX4270 AV = +5V/V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Small-Signal -3dB Bandwidth Full-Power Bandwidth 0.1dB Gain Flatness SYMBOL BW-3dB FPBW BW0.1dB All-Hostile Crosstalk CONDITIONS VOUT = 100mVp-p VOUT = 1Vp-p VOUT = 100mVp-p MIN TYP MAX4265/MAX4268 300 MAX4266/MAX4269 350 MAX4267/MAX4270 200 MAX4265/MAX4268 175 MAX4266/MAX4269 200 MAX4267/MAX4270 200 MAX4265/MAX4268 100 MAX4266/MAX4269 35 MAX4267/MAX4270 35 MAX UNITS MHz MHz MHz f = 10MHz 85 dB SR VOUT = 1V step 900 V/µs Rise/Fall Times tR, tF VOUT = 1V step Settling Time (0.1%) tS,0.1 VOUT = 1V step Slew Rate Spurious-Free Dynamic Range Second Harmonic Distortion Third Harmonic Distortion SFDR VOUT = 1Vp-p (MAX4269) VOUT = 1Vp-p (MAX4269) VOUT = 1Vp-p (MAX4269) 1 ns VOUT = 1V step 15 ns fC = 1MHz 88 fC = 5MHz 90 fC = 10MHz 87 fC = 20MHz 78 fC = 60MHz 68 fC = 100MHz 60 fC = 1MHz 88 fC = 5MHz 90 fC = 10MHz 87 fC = 20MHz 78 fC = 60MHz 68 fC = 100MHz 60 fC = 1MHz 96 fC = 5MHz 95 fC = 10MHz 92 fC = 20MHz 86 fC = 60MHz 72 fC = 100MHz 68 dBc dBc dBc _______________________________________________________________________________________ 3 MAX4265–MAX4270 AC ELECTRICAL CHARACTERISTICS AC ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, VEE = 0, RL = 100Ω to VCC/2, VCM = VCC/2, MAX4265/MAX4268 AV = +1V/V, MAX4266/MAX4269 AV = +2V/V, MAX4267/MAX4270 AV = +5V/V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL Two-Tone, Third-Order Intercept Distortion CONDITIONS MIN TYP VOUT = 1Vp-p, fCA = 20MHz, fCB = 21.25MHz (MAX4269) IP3 Input -1dB Compression Point fC = 20MHz MAX UNITS 35 dBm 12 dBm DG NTSC, f = 3.58MHz, RL = 150Ω to VCC/2 0.015 % Differential Phase DP NTSC, f = 3.58MHz, RL = 150Ω to VCC/2 0.03 degrees Input Capacitance CIN 2 pF Output Impedance ROUT 1 Ω Differential Gain f = 10MHz Disabled Output Capacitance VEN_ = 0 5 pF Enable Time tEN VIN = 1V 100 ns Disable Time tDIS VIN = 1V 750 µs No sustained oscillation Capacitive Load Stability MAX4265/MAX4268 15 MAX4266/MAX4269 15 MAX4267/MAX4270 22 pF Input Voltage Noise Density en f = 1kHz 8 nV/√Hz Input Current Noise Density in f = 1kHz 1 pA/√Hz Typical Operating Characteristics (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) LARGE-SIGNAL GAIN vs. FREQUENCY 2 GAIN (dB) MAX4269 -2 -3 0.3 0.2 MAX4268 1 0 -1 VOUT = 1Vp-p 2 MAX4268 1 0.1 0 -1 MAX4269 -2 MAX4270 -0.2 -0.3 -0.4 -5 -5 -0.5 -6 -6 0.1M 1M 10M FREQUENCY (Hz) 100M 1G MAX4269 -0.1 -4 MAX4270 MAX4268 0 -3 -4 4 3 MAX4268/70 toc3 VOUT = 100mVp-p GAIN FLATNESS vs. FREQUENCY 0.4 GAIN (dB) 3 4 MAX4268/70 toc01a 4 MAX4268/70 toc02a SMALL-SIGNAL BANDWIDTH GAIN (dB) MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable MAX4270 -0.6 0.1M 1M 10M FREQUENCY (Hz) 100M 1G 0.1M 1M 10M FREQUENCY (Hz) _______________________________________________________________________________________ 100M 1G Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable -30 -40 DISTORTION (dBc) -40 VOUT = 1Vp-p -50 -60 -70 -70 2ND HARMONIC -90 3RD HARMONIC -90 VOUT = 1Vp-p -30 -40 2ND HARMONIC 10M 1M 100M -90 0.1M 10M 1M 3RD HARMONIC -100 0.1M 100M 10M 1M 100M MAX4268 DISTORTION vs. LOAD MAX4269 DISTORTION vs. LOAD MAX4270 DISTORTION vs. LOAD -70 -80 -60 -70 -90 3RD HARMONIC -100 200 300 400 500 600 -50 -60 -70 2ND HARMONIC -80 -90 3RD HARMONIC -100 100 MAX4268/70 toc09 -40 2ND HARMONIC -80 2ND HARMONIC -90 -50 fO = 5MHz VOUT = 1Vp-p -30 DISTORTION (dBc) -40 DISTORTION (dBc) -60 fO = 5MHz VOUT = 1Vp-p -30 -20 MAX4268/70 toc08 -20 MAX4268/70 toc07 -50 3RD HARMONIC -100 0 100 200 300 400 500 600 0 100 200 300 400 500 RESISTIVE LOAD (Ω) RESISTIVE LOAD (Ω) MAX4268 DISTORTION vs. VOLTAGE SWING MAX4269 DISTORTION vs. VOLTAGE SWING MAX4270 DISTORTION vs. VOLTAGE SWING -40 -60 -70 2ND HARMONIC -80 -50 -60 -70 2ND HARMONIC -80 -90 -100 1.0 1.5 VOLTAGE SWING (Vp-p) 2.0 2.5 -50 -60 -70 2ND HARMONIC -90 3RD HARMONIC -100 -100 0.5 -40 -80 3RD HARMONIC -90 3RD HARMONIC fO = 5MHz -30 DISTORTION (dBc) -50 fO = 5MHz -30 DISTORTION (dBc) -40 -20 MAX4268/70 toc11 -20 MAX4268/70 toc10 fO = 5MHz 600 MAX4268/70 toc12 RESISTIVE LOAD (Ω) -30 0 2ND HARMONIC FREQUENCY (Hz) -40 -20 -70 FREQUENCY (Hz) fO = 5MHz VOUT = 1Vp-p 0 -60 FREQUENCY (Hz) -20 -30 -50 -80 3RD HARMONIC -100 0.1M DISTORTION (dBc) -60 -80 -100 DISTORTION (dBc) -50 -80 -20 DISTORTION (dBc) -30 MAX4270 DISTORTION vs. FREQUENCY MAX4268/70 toc05 VOUT = 1Vp-p DISTORTION (dBc) -20 MAX4268/70 toc04 -20 MAX4269 DISTORTION vs. FREQUENCY MAX4268/70 toc06 MAX4268 DISTORTION vs. FREQUENCY 0 0.5 1.0 1.5 VOLTAGE SWING (Vp-p) 2.0 2.5 0 0.5 1.0 1.5 2.0 2.5 VOLTAGE SWING (Vp-p) _______________________________________________________________________________________ 5 MAX4265–MAX4270 Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) SPURIOUS-FREE DYNAMIC RANGE vs. FREQUENCY -30 -50 -60 MAX4270 -70 50 MAX4269 -80 MAX4268 MAX4269 55 INTERCEPT (dBm) -40 SFDR (dBc) MAX4270 0.01 60 MAX4268/70 toc14 VOUT = 1Vp-p 10M 1M 10M 1M 100M 0.1M FREQUENCY (Hz) VOLTAGE NOISE vs. FREQUENCY OUTPUT IMPEDANCE vs. FREQUENCY MAX4268/MAX4269/MAX4290 CROSSTALK vs. FREQUENCY 10 1 100 1k 10k 100k 1M 0.01 0.1M 10M FREQUENCY (Hz) IRE 10M 100M 10 0.1M 1G 1M 10M 100M 1G FREQUENCY (Hz) FREQUENCY (Hz) MAX4269 DIFFERENTIAL GAIN AND PHASE MAX4270 DIFFERENTIAL GAIN AND PHASE 0.020 0.010 0.000 -0.010 -0.020 -0.030 100 -80 -120 1M MAX4268/70 toc20 DIFF GAIN (%) MAX4268/70 toc19 MAX4268 DIFFERENTIAL GAIN AND PHASE 0.020 0.015 0.010 0.005 0.000 -0.005 -60 IRE MAX4268/70 toc21 10 -40 -100 DIFF GAIN (%) 1 MAX4268/70 toc18 -20 CROSSTALK (dB) 100 100M 0 MAX4268/70 toc17 MAX4268/70 toc16 1000 0.1 DIFF GAIN (%) 10M 1M FREQUENCY (Hz) 10 10 MAX4268 FREQUENCY (Hz) 100 1 MAX4270 35 20 0.1M 100M 40 25 MAX4268 -100 0.001 0.1M MAX4269 45 30 -90 OUTPUT IMPEDANCE (Ω) THD + NOISE (%) VOUT = 1Vp-p VOLTAGE NOISE (nV/√Hz) -20 MAX4268/70 toc13 0.1 TWO-TONE THIRD-ORDER INTERCEPT vs. FREQUENCY MAX4268/70 toc15 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY 0.006 0.004 0.002 0.000 -0.002 -0.004 -0.006 100 10 IRE 100 10 IRE 100 0.010 10 RL = 150Ω 6 IRE 100 0.012 0.008 0.004 0.000 -0.004 -0.008 DIFF PHASE (°) 0.04 0.03 0.02 0.01 0.00 -0.01 DIFF PHASE (°) DIFF PHASE (°) MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable 10 RL = 150Ω IRE 100 0.000 -0.010 -0.020 -0.030 RL = 150Ω _______________________________________________________________________________________ Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable COMMON-MODE REJECTION RATIO vs. FREQUENCY -10 -20 CMRR (dB) -30 -40 -50 -60 -40 -50 -60 -70 3.5 3.0 2.5 2.0 1.5 -70 -90 -80 0.5 -100 -90 0 1M 10M 100M 10k 1G 100k 1M 10M 100M 1.0 1G VOL 0 200 400 FREQUENCY (Hz) FREQUENCY (Hz) 800 1000 SHUTDOWN/ENABLE RESPONSE MAX4268/70 toc26 MAX4268/70 toc25 INPUT TO SHUTDOWN 5V VCC 2.5V/div 600 LOAD (Ω) POWER-UP/POWER-DOWN RESPONSE 0V 5V OUTPUT 500mV/div 0V OUTPUT 500mV/div ENABLED SHUT DOWN 5µs/div 250ns/div INPUT OFFSET VOLTAGE vs. SUPPLY VOLTAGE INPUT BIAS CURRENT vs. SUPPLY VOLTAGE -1.00 -1.05 -1.10 MAX4268/70 toc28 -0.95 -5.0 -4.5 INPUT BIAS CURRENT (µA) -0.90 MAX4268/70 toc27 0.1M VOH 4.0 -80 INPUT OFFSET VOLTAGE (mV) PSRR (dB) -30 4.5 OUTPUT VOLTAGE SWING (V) -20 5.0 MAX14268/70 toc23 0 MAX4268/70 toc22 0 -10 OUTPUT VOLTAGE SWING vs. RESISTIVE LOAD MAX4268/70 toc24 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -1.15 -0.5 -1.20 -0 4.5 5.0 5.5 6.0 6.5 7.0 SUPPLY VOLTAGE (V) 7.5 8.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 7 MAX4265–MAX4270 Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) SUPPLY CURRENT (PER AMPLIFIER) vs. SUPPLY VOLTAGE 32 31 30 29 28 27 4 26 3 2 1 0 -1 -2 -3 -4 25 -5 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 -50 -35 -20 -5 10 25 40 55 SUPPLY VOLTAGE (V) TEMPERATURE (°C) INPUT BIAS CURRENT vs. TEMPERATURE INPUT OFFSET CURRENT vs. TEMPERATURE 3 2 1 85 70 85 MAX4268/70 toc32 4 70 500 400 INPUT OFFSET CURRENT (nA) MAX4268/70 toc31 5 INPUT BIAS CURRENT (µA) MAX4268/70 toc30 33 5 INPUT OFFSET VOLTAGE (mV) 34 SUPPLY CURRENT (mA) INPUT OFFSET VOLTAGE vs. TEMPERATURE MAX4268/70 toc29 35 300 200 100 0 -100 -200 -300 -400 -500 0 10 25 40 55 70 -50 -35 -20 -5 85 10 25 40 55 TEMPERATURE (°C) TEMPERATURE (°C) SUPPLY CURRENT (PER AMPLIFIER) vs. TEMPERATURE VOLTAGE SWING vs. TEMPERATURE 5 MAX4268/70 toc33 35 34 4 VOLTAGE SWING (V) 33 32 31 30 29 28 VOH 3 2 1 27 MAX4268/70 toc34 -50 -35 -20 -5 SUPPLY CURRENT (mA) MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable VOL 26 0 25 -50 -35 -20 -5 10 25 40 TEMPERATURE (°C) 8 55 70 85 -50 -35 -20 -5 10 25 40 55 TEMPERATURE (°C) _______________________________________________________________________________________ 70 85 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable MAX4269 SMALL-SIGNAL PULSE RESPONSE MAX4268/70 toc35 MAX4268/70 toc36 MAX4268 SMALL-SIGNAL PULSE RESPONSE INPUT 50mV/div INPUT 25mV/div OUTPUT 50mV/div OUTPUT 50mV/div 5ns/div MAX4270 SMALL-SIGNAL PULSE RESPONSE MAX4268 LARGE-SIGNAL PULSE RESPONSE MAX4268/70 toc37 MAX4268/70 toc38 5ns/div INPUT 10mV/div INPUT 500mV/div OUTPUT 50mV/div OUTPUT 500mV/div 5ns/div MAX4269 LARGE-SIGNAL PULSE RESPONSE MAX4270 LARGE-SIGNAL PULSE RESPONSE MAX4268/70 toc39 MAX4268/70 toc40 5ns/div INPUT 250mV/div INPUT 100mV/div OUTPUT 500mV/div OUTPUT 500mV/div 5ns/div 5ns/div _______________________________________________________________________________________ 9 MAX4265–MAX4270 Typical Operating Characteristics (continued) (VCC = +5V, VEE = 0, EN_ = 5V, RL = 100Ω to VCC/2, MAX4268 AV = +1V/V, MAX4269 AV = +2V/V, MAX4270 AV = +5V/V, TA =+25°C, unless otherwise noted.) MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable Pin Description PIN MAX4265 MAX4266 MAX4267 MAX4268 MAX4269 MAX4270 NAME FUNCTION 8 µMAX/SO 14 SO 16 QSOP FUNCTION 1 — — EN Enable Input. Active high. Connect to VCC for normal operation. — 4, 5 4, 5 ENA, ENB Enable Input. Active high. Connect to VCC for normal operation. 2 — — IN- Inverting Input — 2, 9 2, 11 INA-, INB- Inverting Input 3 — — IN+ Noninverting Input — 3, 10 3, 12 INA+, INB+ Noninverting Input 4, 5 6, 7 6, 7 VEE Negative Power Supply 6 — — OUT Amplifier Output — 1, 8 1, 10 OUTA, OUTB Amplifier Output 7, 8 13, 14 15, 16 VCC Positive Power Supply. Connect to a +4.5V to +8.0V supply and bypass with a 0.1µF capacitor for single-supply operation. — 11, 12 8, 9, 13, 14 N.C. No Connection. Not internally connected. _______________Detailed Description The MAX4265–MAX4270 single-supply operational amplifiers feature ultra-low distortion and wide bandwidth. Their low distortion and low noise make them ideal for driving high-speed analog-to-digital converters (ADCs) up to 16 bits in telecommunications applications and high-performance signal processing. These devices can drive loads as low as 100Ω and deliver 45mA while maintaining DC accuracy and AC performance. The input common-mode voltage ranges from (V EE + 1.6V) to (V CC - 1.6V), while the output swings to within 1.1V of the rails. Low Distortion The MAX4265–MAX4270 use proprietary bipolar technology to achieve minimum distortion in single-supply systems—a feature typically available only in dual-supply op amps. Several factors can affect the noise and distortion that a device contributes to the input signal. The following guidelines explain how various design choices impact the total harmonic distortion (THD). 10 • Choose the proper feedback-resistor and gain-resistor values for the application. In general, the smaller the closed-loop gain, the smaller the THD generated—especially when driving heavy resistive loads. Large-value feedback resistors can significantly improve distortion. The MAX4265–MAX4270’s THD normally increases at approximately 20dB per decade at frequencies above 1MHz; this is a lower rate than that of comparable dual-supply op amps. • Operating the device near or above the full-power bandwidth significantly degrades distortion (see the Total Harmonic Distortion vs. Frequency graph in the Typical Operating Characteristics). • The decompensated devices (MAX4266/MAX4267/ MAX4269/MAX4270) deliver the best distortion performance since they have a slightly higher slew rate and provide a higher amount of loop gain for a given closed-loop gain setting. ______________________________________________________________________________________ Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable Driving Capacitive Loads Unity-Gain Configurations The MAX4265 and MAX4268 are internally compensated for unity gain. When configured for unity gain, they require a small resistor (RF) in series with the feedback path (Figure 1). This resistor improves AC response by reducing the Q of the tank circuit, which is formed by parasitic feedback inductance and capacitance. The MAX4265–MAX4270 are not designed to drive highly reactive loads; stability is maintained with loads up to 15pF with less than 2dB peaking in the frequency response. To drive higher capacitive loads, place a small isolation resistor in series between the amplifier’s output and the capacitive load (Figure 1). This resistor improves the amplifier’s phase margin by isolating the capacitor from the op amp’s output. To ensure a load capacitance that limits peaking to less than 2dB, select a resistance value from Figure 2. For example, if the capacitive load is 100pF, the corresponding isolation resistor is 6Ω (MAX4269). Figures 3 and 4 show the peaking that occurs in the frequency response with and without an isolation resistor. Inverting and Noninverting Configurations The values of the gain-setting feedback and input resistors are important design considerations. Large resistor values will increase voltage noise and interact with the amplifier’s input and PC board capacitance to generate undesirable poles and zeros, which can decrease bandwidth or cause oscillations. For example, a noninverting gain of +2V/V (Figure 1) using RF = RG = 1kΩ combined with 2pF of input capacitance and 0.5pF of board capacitance will cause a feedback pole at 128MHz. If this pole is within the anticipated amplifier bandwidth, it will jeopardize stability. Reducing the 1kΩ resistors to 100Ω extends the pole frequency to 1.28GHz, but could limit output swing by adding 200Ω in parallel with the amplifier’s load. Clearly, the selection of resistor values must be tailored to the specific application. Distortion Considerations The MAX4265–MAX4270 are ultra-low-distortion, highbandwidth op amps. Output distortion will degrade as the total load resistance seen by the amplifier decreases. To minimize distortion, keep the input and gain-setting resistor values relatively large. A 500Ω feedback resistor combined with an appropriate input resistor to set the gain will provide excellent AC performance without significantly increasing distortion. Noise Considerations The amplifier’s input-referred noise-voltage density is dominated by flicker noise at lower frequencies and by thermal noise at higher frequencies. Because the thermal noise contribution is affected by the parallel combination of the feedback resistive network, those resistor values should be reduced in cases where the system bandwidth is large and thermal noise is dominant. This noise-contribution factor decreases, however, with increasing gain settings. For example, the input noise voltage density at the op amp input with a gain of +10V/V using R F = 100kΩ and R G = 11kΩ is e n = 18nV/√Hz. The input noise can be reduced to 8nV/√Hz by choosing RF = 1kΩ, RG = 110Ω. Coaxial cable and other transmission lines are easily driven when terminated at both ends with their characteristic impedance. When driving back-terminated transmission lines, the capacitive load of the transmission line is essentially eliminated. ADC Input Buffer Input buffer amplifiers can be a source of significant errors in high-speed ADC applications. The input buffer is usually required to rapidly charge and discharge the ADC’s input, which is often capacitive (see Driving Capacitive Loads). In addition, since a high-speed ADC’s input impedance often changes very rapidly during the conversion cycle, measurement accuracy must RG RF RS* VIN CL MAX4265 MAX4266 MAX4267 PART RF (Ω) RG (Ω) GAIN (V/V) MAX4265 MAX4266 24 500 ∞ 500 1 2 MAX4267 500 125 5 RL *OPTIONAL, USED TO MINIMIZE PEAKING FOR CL > 15pF. Figure 1. Noninverting Configuration ______________________________________________________________________________________ 11 MAX4265–MAX4270 Choosing Resistor Values Low-Power Disable Mode The MAX4265–MAX4270 feature an active-high enable pin that can be used to save power and place the outputs in a high-impedance state. Drive EN_ with logic levels or connect EN_ to VCC for normal operation. In the dual versions (MAX4268/MAX4269/MAX4270), each individual op amp is enabled separately, allowing the devices to be used in a multiplex configuration. The supply current in low-power mode is reduced to 1.6mA per device. Enable time is typically 100ns, and disable time is typically 750µs. 15 MAX4268 0 0 40 4 3 CL = 5.1pF 80 100 120 CL = 7.3pF 2 GAIN (dB) 1 0 CL = 7.3pF CL = 5.1pF 1 0 -1 CL = 2.2pF -2 CL = 2.2pF -3 -4 -4 -5 -5 0.1M 1M 10M 100M 0.1M 1G 1M Figure 3a. MAX4268 Small-Signal Gain vs. Frequency Without Isolation Resistor 5 3 4 3 CL = 15pF 2 0 1 GAIN (dB) 1 -1 -2 CL = 10pF -3 CL = 7.3pF 100M 1G Figure 3b. MAX4269 Small-Signal Gain vs. Frequency Without Isolation Resistor 4 2 10M FREQUENCY (Hz) FREQUENCY (Hz) CL = 10pF RISO = 12Ω CL = 10pF RISO = 15Ω 0 CL = 10pF RISO = 18Ω -1 -2 -4 -3 -5 -4 -5 -6 0.1M 1M 10M 100M 1G FREQUENCY (Hz) Figure 3c. MAX4270 Small-Signal Gain vs. Frequency Without Isolation Resistor 12 60 Figure 2. MAX4268/MAX4269/MAX4270 Isolation Resistance vs. Capacitive Load 3 -3 20 CLOAD (pF) 5 -2 MAX4270 5 4 -1 MAX4269 10 5 2 GAIN (dB) 20 RISO (Ω) be maintained using an amplifier with very low output impedance at high frequencies. The combination of high speed, fast slew rate, low noise, and a low and stable distortion over load makes the MAX4265– MAX4270 ideally suited for use as buffer amplifiers in high-speed ADC applications. GAIN (dB) MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable 0.1M 1M 10M 100M 1G FREQUENCY (Hz) Figure 4a. MAX4268 Small-Signal Gain vs. Frequency With Isolation Resistor ______________________________________________________________________________________ Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable 4 4 3 3 CL = 10pF RISO = 12Ω CL = 10pF RISO = 15Ω 1 0 -1 CL = 10pF RISO = 18Ω -2 CL = 22pF RISO = 3.9Ω 1 GAIN (dB) GAIN (dB) 2 CL = 22pF RISO = 22Ω 2 0 -1 CL = 22pF RISO = 6Ω -2 -3 -3 -4 -4 -5 -5 -6 0.1M 1M 10M 100M 1G FREQUENCY (Hz) Figure 4b. MAX4269 Small-Signal Gain vs. Frequency With Isolation Resistor Power Supplies and Layout The MAX4265–MAX4270 operate from a single +4.5V to +8.0V power supply or from dual ±2.25V to ±4.0V supplies. For single-supply operation, bypass each power-supply input with a 0.1µF ceramic capacitor placed close to the VCC pins, and an additional 10µF to VEE. When operating from dual supplies, bypass each supply to ground. 0.1M 1M 10M 100M 1G FREQUENCY (Hz) Figure 4c. MAX4270 Small-Signal Gain vs. Frequency With Isolation Resistor Chip Information TRANSISTOR COUNT: MAX4265/66/67: 132 MAX4268/69/70: 285 Good layout improves performance by decreasing the amount of stray capacitance and noise at the op amp’s inputs and output. To decrease stray capacitance, minimize PC board trace lengths and resistor leads, and place external components close to the op amp’s pins. ______________________________________________________________________________________ 13 MAX4265–MAX4270 5 MAX4265–MAX4270 Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable Pin Configurations TOP VIEW EN 1 8 IN- 2 IN+ 3 7 MAX4265 MAX4266 MAX4267 VEE 4 µMAX/SO 14 VCC VCC OUTA 1 16 VCC OUTA 1 14 VCC INA- 2 15 VCC INA- 2 13 VCC INA+ 3 14 N.C. INA+ 3 12 N.C. ENA 4 ENB 5 6 OUT 5 VEE MAX4268 MAX4269 MAX4270 11 N.C. 10 INB+ VEE 6 9 INB- VEE 7 8 OUTB SO ENA 4 ENB 5 MAX4268 MAX4269 MAX4270 13 N.C. 12 INB+ VEE 6 11 INB- VEE 7 10 OUTB N.C. 8 9 QSOP ______________________________________________________________________________________ N.C. Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable 8LUMAXD.EPS SOICN.EPS ______________________________________________________________________________________ 15 MAX4265–MAX4270 Package Information Ultra-Low-Distortion, Single-Supply, 300MHz Op Amps with Enable QSOP.EPS MAX4265–MAX4270 Package Information (continued) 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 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.