19-4757; Rev 3; 10/98 L MANUA ION KIT HEET T A U L EVA TA S WS DA FOLLO 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 The MAX4104/MAX4105/MAX4304/MAX4305 op amps feature ultra-high speed, low noise, and low distortion in a SOT23 package. The unity-gain-stable MAX4104 requires only 20mA of supply current while delivering 625MHz bandwidth and 400V/µs slew rate. The MAX4304, compensated for gains of +2V/V or greater, delivers a 730MHz bandwidth and a 1000V/µs slew rate. The MAX4105 is compensated for a minimum gain of +5V/V and delivers a 410MHz bandwidth and a 1400V/sec slew rate. The MAX4305 has +10V/V minimum gain compensation and delivers a 340MHz bandwidth and a 1400V/µs slew rate. Low voltage noise density of 2.1nV/√Hz and -88dBc spurious-free dynamic range make these devices ideal for low-noise/low-distortion video and telecommunications applications. These op amps also feature a wide output voltage swing of ±3.7V and ±70mA output currentdrive capability. For space-critical applications, they are available in a miniature 5-pin SOT23 package. Features ♦ Low 2.1nV/√Hz Voltage Noise Density ♦ Ultra-High 740MHz -3dB Bandwidth (MAX4304, AVCL = 2V/V) ♦ 100MHz 0.1dB Gain Flatness (MAX4104/4105) ♦ 1400V/µs Slew Rate (MAX4105/4305) ♦ -88dBc SFDR (5MHz, RL = 100Ω) (MAX4104/4304) ♦ High Output Current Drive: ±70mA ♦ Low Differential Gain/Phase Error: 0.01%/0.01° (MAX4104/4304) ♦ Low ±1mV Input Offset Voltage ♦ Available in Space-Saving 5-Pin SOT23 Package Selector Guide PART ________________________Applications Video ADC Preamp Pulse/RF Telecom Applications Video Buffers and Cable Drivers MINIMUM BANDWIDTH STABLE (MHz) GAIN (V/V) PIN-PACKAGE MAX4104 1 625 5-pin SOT23, 8-pin SO MAX4304 MAX4105 MAX4305 2 5 10 740 410 340 5-pin SOT23, 8-pin SO 5-pin SOT23, 8-pin SO 5-pin SOT23, 8-pin SO Ultrasound Ordering Information Active Filters ADC Input Buffers Typical Application Circuit PART TEMP. RANGE PINPACKAGE MAX4104ESA -40°C to +85°C 8 SO MAX4104EUK-T -40°C to +85°C SOT TOP MARK — 5 SOT23-5 ACCO Ordering Information continued at end of data sheet. Pin Configurations INPUT MAX4304 8 to 16-BIT HIGH-SPEED ADC TOP VIEW OUT 1 5 VCC MAX4104 MAX4105 MAX4304 MAX4305 VEE 2 330Ω IN+ 3 330Ω 4 IN- SOT23-5 ADC BUFFER WITH GAIN (AVCL = 2V/V) 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 1-800-835-8769. MAX4104/MAX4105/MAX4304/MAX4305 General Description MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE)................................................+12V Voltage on Any Pin to Ground..........(VEE - 0.3V) to (VCC + 0.3V) Short-Circuit Duration (VOUT to GND)........................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 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, VCM = 0, RL = 100kΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Operating Supply Voltage Range Input Offset Voltage Input Offset-Voltage Drift Input Bias Current SYMBOL VCC/VEE VOS CONDITIONS MIN TYP MAX UNITS ±3.5 ±5 ±5.5 V MAX4_0_ESA 1 6 MAX4_0_EUK 1 8 Guaranteed by PSRR test VOUT = 0 TCVOS 2.5 mV µV/°C IB 32 70 Input Offset Current IOS 0.5 5.0 Differential Input Resistance RIN -0.8V ≤ VIN ≤ 0.8V Common-Mode Input Resistance RIN Either input Input Common-Mode Voltage Range VCM Guaranteed by CMRR test µA µA 6 kΩ 1.5 MΩ -2.8 +4.1 V Common-Mode Rejection Ratio CMRR -2.8V ≤ VCM ≤ 4.1V 80 95 dB Positive Power-Supply Rejection Ratio PSSR+ VCC = 3.5V to 5.5V 75 85 dB Negative Power-Supply Rejection Ratio PSRR- VEE = -3.5V to -5.5V 55 65 dB 55 65 Quiescent Supply Current Open-Loop Gain IS AVOL Output Voltage Swing VOUT Output Current Drive IOUT Short-Circuit Output Current Open-Loop Output Impedance 2 ISC ZOUT VOUT = 0 -2.8V ≤ VOUT ≤ 2.8V, RL = 100Ω 20 RL = 100kΩ ±3.5 -3.7 to +3.8 RL = 100Ω ±3.0 -3.5 to +3.4 RL = 30Ω ±53 RL = short to ground 27 mA dB V ±70 mA 80 mA 9 Ω _______________________________________________________________________________________ 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 (VCC = +5V, VEE = -5V, VCM = 0, RL = 100Ω; AV = +1V/V for MAX4104, +2V/V for MAX4304, +5V/V for MAX4105, +10V/V for MAX4305; TA = +25°C; unless otherwise noted.) PARAMETER -3dB Bandwidth SYMBOL BW(-3dB) 0.1dB Bandwidth BW(0.1) Full-Power Bandwidth Slew Rate FPBW SR Settling Time to 0.1% Spurious-Free Dynamic Range tS SFDR CONDITIONS VOUT = 100mVp-p VOUT = 100mVp-p VOUT = 2Vp-p VOUT = 2Vp-p TYP MAX4104 625 MAX4304 740 MAX4105 410 MAX4305 340 MAX4104 100 MAX4304 60 MAX4105 80 MAX4305 70 MAX4104 115 MAX4304 285 MAX4105 370 MAX4305 320 MAX4104 400 MAX4304 1000 MAX4105 1400 MAX4305 1400 to 0.1% 20 to 0.01% 25 MAX4104/ MAX4304 fC = 5MHz -88 fC = 20MHz -67 MAX4105/ MAX4305 fC = 5MHz -74 fC = 20MHz -61 VOUT = 2Vp-p VOUT = 2Vp-p MIN MAX4104/MAX4304 0.01 MAX4105/MAX4305 0.02 MAX4104/MAX4304 0.01 MAX4105/MAX4305 0.02 MAX UNITS MHz MHz MHz V/µs ns dBc Differential Gain Error DG NTSC, RL = 150Ω Differential Phase Error DP NTSC, RL = 150Ω Input Voltage Noise Density en f = 1MHz 2.1 nV/√Hz Input Current Noise Density in f = 1MHz 3.1 pA/√Hz ZOUT f = 10MHz 1 Ω Output Impedance % degrees _______________________________________________________________________________________ 3 MAX4104/MAX4105/MAX4304/MAX4305 AC ELECTRICAL CHARACTERISTICS __________________________________________Typical Operating Characteristics (VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.) MAX4304 SMALL-SIGNAL GAIN vs. FREQUENCY (AVCL = +2) 1 0 -1 -2 3 4 2 1 0 -1 -2 2 1 0 -1 -2 -3 -4 -4 -4 -5 -5 -5 100M 1G 100k 1M 10M 100M 1G 100k MAX4304 GAIN FLATNESS vs. FREQUENCY (AVCL = +2) 0.5 0.4 0.1 GAIN (dB) 1 -1 0.5 0 -0.1 0.3 0.2 0.1 0 -0.1 -2 -0.2 -3 -0.3 -4 -0.4 -0.4 -5 -0.5 -0.5 1M 10M 100M 1G VOUT = 100mVp-p 0.4 NORMALIZED GAIN (dB) 0.3 0.2 0 VOUT = 100mVp-p -0.2 -0.3 100k 1M 10M 100M 100k 1G 1M 10M 100M FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) MAX4105 GAIN FLATNESS vs. FREQUENCY (AVCL = +5) MAX4305 GAIN FLATNESS vs. FREQUENCY (AVCL = +10) MAX4104 LARGE-SIGNAL GAIN vs. FREQUENCY (AVCL = +1) 0.2 0.1 0 -0.1 VOUT = 100mVp-p 0.3 NORMALIZED GAIN (dB) 0.3 0.4 5 4 2 0.1 1 0 -0.1 0 -1 -0.2 -2 -0.3 -0.3 -3 -0.4 -0.4 -4 -0.5 -0.5 -5 -0.2 1M 10M FREQUENCY (Hz) 100M 1G 100k 1M 10M FREQUENCY (Hz) 100M 1G VOUT = 2Vp-p 3 0.2 GAIN (dB) VOUT = 100mVp-p 1G MAX4104 TOC9 0.5 MAX4104 TOC 7 0.5 1G MAX4104 TOC 6 MAX4104 GAIN FLATNESS vs. FREQUENCY (AVCL = +1) 2 100k 100M MAX4305 SMALL-SIGNAL GAIN vs. FREQUENCY (AVCL = +10) 3 0.4 10M FREQUENCY (Hz) VOUT = 100mVp-p 100k 1M FREQUENCY (Hz) MAX4104 TOC 5 4 10M -3 FREQUENCY (Hz) MAX4104 TOC 4 5 1M VOUT = 100mVp-p 3 -3 100k NORMALIZED GAIN (dB) 5 MAX4104 TOC 8 GAIN (dB) 2 VOUT = 100mVp-p 4 NORMALIZED GAIN (dB) 3 4 5 NORMALIZED GAIN (dB) VOUT = 100mVp-p MAX4104 TOC 2 4 MAX4104 TOC01 5 MAX4105 SMALL-SIGNAL GAIN vs. FREQUENCY (AVCL = +5) MAX4104 TOC 3 MAX4104 SMALL-SIGNAL GAIN vs. FREQUENCY (AVCL = +1) NORMALIZED GAIN (dB) MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 100k 1M 10M FREQUENCY (Hz) _______________________________________________________________________________________ 100M 1G 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 0 -1 -2 3 1 0 -1 -2 2 1 0 -1 -2 -3 -3 -4 -4 -4 -5 -5 -5 1M 10M 100M 1G -3 100k 1M 10M 100M 1G 100k 1M 10M 100M FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) POSITIVE POWER-SUPPLY REJECTION vs. FREQUENCY NEGATIVE POWER-SUPPLY REJECTION vs. FREQUENCY COMMON-MODE REJECTION vs. FREQUENCY -40 -50 -60 -70 -80 0 -10 -20 -10 -30 -20 -40 -30 -50 -40 -60 -50 -70 -60 -80 -90 -70 -90 -100 -80 -100 100k 1M 10M 100M 1G 100k 1M 10M 100M 10k 1G 100k 1M 10M 100M FREQUENCY (Hz) FREQUENCY (Hz) FREQUENCY (Hz) VOLTAGE NOISE DENSITY vs. FREQUENCY (INPUT REFERRED) CURRENT NOISE DENSITY vs. FREQUENCY (INPUT REFERRED) CLOSED-LOOP OUTPUT IMPEDANCE vs. FREQUENCY 1 10 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M MAX4104 TOC-R 1G 100 10 1 0.1 1 1 1000 OUTPUT IMPEDANCE (Ω) 10 100 MAX4104 TOC-Q MAX4104 TOC-P 100 1G MAX4104 TOCO 10 CMR (dB) -30 0 MAX4104 TOCN -20 20 POWER-SUPPLY REJECTION (dB) MAX4104 TOCM 0 -10 POWER-SUPPLY REJECTION (dB) 2 VOUT = 2Vp-p 4 NORMALIZED GAIN (dB) 1 100k VOLTAGE NOISE DENSITY (nV/√Hz) 3 NORMALIZED GAIN (dB) 2 CURRENT NOISE DENSITY (pA/√Hz) NORMALIZED GAIN (dB) 3 VOUT = 2Vp-p 4 5 MAX4104 TOC 11 VOUT = 2Vp-p 4 MAX4305 LARGE-SIGNAL GAIN vs. FREQUENCY (AVCL = +10) 5 MAX4104 TOC10 5 MAX4105 LARGE-SIGNAL GAIN vs. FREQUENCY (AVCL = +5) MAX4104 TOC12 MAX4304 LARGE-SIGNAL GAIN vs. FREQUENCY (AVCL = +2) 0.01 1 10 100 1k 10k 100k FREQUENCY (Hz) 1M 10M 100k 1M 10M 100M 1G FREQUENCY (Hz) _______________________________________________________________________________________ 5 MAX4104/MAX4105/MAX4304/MAX4305 Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.) -0.010 RL = 150Ω RL = 150Ω 0 DIFF PHASE (deg) 0.015 RL = 150Ω 0.005 0.000 0 0.025 0.020 0.015 0.010 0.005 0.000 -0.005 100 RL = 150Ω MAX4104 TOC-U VOUT = 2Vp-p -20 -30 -40 -50 -60 -70 2ND HARMONIC -80 -90 3RD HARMONIC -100 0 100 0 -10 100 100k 1M 10M IRE IRE FREQUENCY (Hz) MAX4105/MAX4305 HARMONIC DISTORTION vs. FREQUENCY MAX4104/MAX4304 HARMONIC DISTORTION vs. LOAD MAX4105/MAX4305 HARMONIC DISTORTION vs. LOAD -40 -50 2ND HARMONIC -60 3RD HARMONIC -80 -30 -40 -50 -60 2ND HARMONIC -70 3RD HARMONIC -80 -40 -50 -60 -90 -100 -100 0 100 200 300 400 500 600 700 800 900 1k 0 100 200 300 400 500 600 700 800 900 1k FREQUENCY (Hz) LOAD (Ω) LOAD (Ω) MAX4104/MAX4304 HARMONIC DISTORTION vs. OUTPUT SWING MAX4105/MAX4305 HARMONIC DISTORTION vs. OUTPUT SWING 100M MAX4104 TOC-Y 0 f = 5MHz -20 -30 -40 -50 -60 2ND HARMONIC -70 3RD HARMONIC -90 OUTPUT SWING vs. LOAD RESISTANCE 0 f = 5MHz -10 -20 -30 -40 -50 2ND HARMONIC -60 -70 -80 3RD HARMONIC 2.0 2.5 3.0 OUTPUT SWING (Vp-p) 3.5 4.0 6 5 4 3 1 -100 1.5 7 2 -90 -100 8 OUTPUT SWING (Vp-p) 10M MAX4104 TOC-Z 1M HARMONIC DISTORTION (dBc) 100k 1.0 3RD HARMONIC -80 -100 0.5 2ND HARMONIC -70 -90 -80 MAX4104 TOC-X -30 -90 -10 f = 5MHz VOUT = 2Vp-p -20 MAX4104 TOCAA -70 -20 100M 0 -10 HARMONIC DISTORTION (dBc) -30 MAX4104 TOC-W -20 f = 5MHz VOUT = 2Vp-p -10 HARMONIC DISTORTION (dBc) VOUT = 2Vp-p -10 0 MAX4104 TOC-V 0 DISTORTION (dBc) 0.00 100 -0.005 6 0.01 -0.01 0 0.010 0.02 HARMONIC DISTORTION (dBc) -0.005 0.03 MAX4104/MAX4304 HARMONIC DISTORTION vs. FREQUENCY MAX4104 TOC T 0.000 DIFF GAIN (%) 0.005 -0.015 DIFF PHASE (deg) MAX4105/MAX4305 DIFFERENTIAL GAIN AND PHASE MAX4104 TOC-S DIFF GAIN (%) MAX4104/MAX4304 DIFFERENTIAL GAIN AND PHASE HARMONIC DISTORTION (dBc) MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT SWING (Vp-p) 3.5 4.0 0 50 100 150 200 250 300 350 400 LOAD RESISTANCE (Ω) _______________________________________________________________________________________ 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 INPUT OFFSET CURRENT vs. TEMPERATURE 2 1 0 -1 MAX4104 TOC-DD 3 INPUT BIAS CURRENT (µA) MAX4104 TOC-CC 35 34 33 32 31 -2 -3 -15 10 35 60 30 -40 85 -15 10 TEMPERATURE (°C) 35 60 85 -40 22 21 20 19 18 24 23 22 21 20 19 18 17 17 16 16 -15 10 35 60 3.6 3.5 RL = 100kΩ 3.2 9.5 10.0 10.5 11.0 -40 SUPPLY VOLTAGE (V) TEMPERATURE (°C) +50mV -50mV 35 60 85 MAX4104 TOCJJ IN +25mV GND 10 MAX4105 SMALL-SIGNAL PULSE RESPONSE (AV = +5) MAX4104 TOCII MAX4104 TOCHH -15 TEMPERATURE (°C) MAX4304 SMALL-SIGNAL PULSE RESPONSE (AV = +2) MAX4104 SMALL-SIGNAL PULSE RESPONSE (AV = +1) IN 3.7 3.3 9.0 85 RL = 100kΩ 3.8 3.4 15 15 85 3.9 VOLTAGE SWING (V) 23 60 4.0 MAX4104 TOC-FF 24 35 POSITIVE OUTPUT VOLTAGE SWING vs. TEMPERATURE 25 SUPPLY CURRENT (mA) MAX4104 TOC-EE 25 10 TEMPERATURE (°C) SUPPLY CURRENT vs. SUPPLY VOLTAGE SUPPLY CURRENT vs. TEMPERATURE -40 -15 TEMPERATURE (°C) MAX4104 TOC-GG -40 SUPPLY CURRENT (mA) INPUT BIAS CURRENT vs. TEMPERATURE 4 INPUT OFFSET CURRENT (µA) 3.0 2.5 2.0 1.5 1.0 0.5 0.0 -0.5 -1.0 -1.5 -2.0 -2.5 -3.0 MAX4104 TOCBB INPUT OFFSET VOLTAGE (mV) INPUT OFFSET VOLTAGE vs. TEMPERATURE IN GND +10mV -25mV -10mV +50mV +50mV GND +50mV GND OUT OUT GND OUT GND -50mV -50mV 10ns/div -50mV 10ns/div 10ns/div _______________________________________________________________________________________ 7 MAX4104/MAX4105/MAX4304/MAX4305 Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.) MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 Typical Operating Characteristics (continued) (VCC = +5V, VEE = -5V, RF = 330Ω, RL = 100Ω, TA = +25°C, unless otherwise noted.) MAX4305 SMALL-SIGNAL PULSE RESPONSE (AV = +10) MAX4104 LARGE-SIGNAL PULSE RESPONSE (AV = +1) MAX4104 TOCKK IN +5mV -5mV MAX4104 TOCLL +1V GND IN GND -1V +50mV +1V OUT OUT GND GND -1V -50mV 10ns/div 10ns/div MAX4305 LARGE-SIGNAL PULSE RESPONSE (AV = +2) MAX4105 LARGE-SIGNAL PULSE RESPONSE (AV = +5) MAX4104 TOCNN MAX4104 TOCMM IN +200mV IN +500mV GND GND -200mV -500mV +1V +1V OUT OUT GND GND -1V -1V 10ns/div 10ns/div MAX4305 LARGE-SIGNAL PULSE RESPONSE (AV = +10) MAX4104 TOCOO IN +100mV GND -100mV +1V OUT GND -1V 10ns/div 8 _______________________________________________________________________________________ 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 PIN NAME FUNCTION 1, 5, 8 N.C. Not internally connected. 4 2 IN- Amplifier Inverting Input 3 3 IN+ Amplifier Noninverting Input 2 4 VEE Negative Power Supply 1 6 OUT Amplifier Output 5 7 VCC Positive Power Supply SOT23-5 SO — _______________Detailed Description The MAX4104/MAX4105/MAX4304/MAX4305 are ultrahigh-speed, low-noise amplifiers featuring -3dB bandwidths up to 880MHz, 0.1dB gain flatness up to 100MHz, and low differential gain and phase errors of 0.01% and 0.01°, respectively. These devices operate on dual power supplies ranging from ±3.5V to ±5.5V and require only 20mA of supply current. The MAX4104/MAX4304/MAX4105/MAX4305 are optimized for minimum closed-loop gains of +1V/V, +2V/V, +5V/V and +10V/V (respectively) with corresponding -3dB bandwidths of 880MHz, 730MHz, 430MHz, and 350MHz. Each device in this family features a low input voltage noise density of only 2.1nV/√Hz (at 1MHz), an output current drive of ±70mA, and spurious-free dynamic range as low as -88dBc (5MHz, RL = 100Ω). ___________Applications Information Layout and Power-Supply Bypassing The MAX4104/MAX4105/MAX4304/MAX4305 have an extremely high bandwidth, and consequently require careful board layout, including the possible use of constant-impedance microstrip or stripline techniques. To realize the full AC performance of these high-speed amplifiers, pay careful attention to power-supply bypassing and board layout. The PC board should have at least two layers: a signal and power layer on one side, and a large, low-impedance ground plane on the other side. The ground plane should be as free of voids as possible. With multilayer boards, locate the ground plane on a layer that incorporates no signal or power traces. Regardless of whether or not a constant-impedance board is used, it is best to observe the following guidelines when designing the board: 1) Do not use wire-wrapped boards (they are much too inductive) or breadboards (they are much too capacitive). 2) Do not use IC sockets. IC sockets increase reactances. 3) Keep signal lines as short and straight as possible. Do not make 90° turns; round all corners. 4) Observe high-frequency bypassing techniques to maintain the amplifier’s accuracy and stability. 5) Bear in mind that, in general, surface-mount components have shorter bodies and lower parasitic reactance, resulting in greatly improved high-frequency performance over through-hole components. The bypass capacitors should include 1nF and 0.1µF ceramic surface-mount capacitors between each supply pin and the ground plane, located as close to the package as possible. Optionally, place a 10µF tantalum capacitor at the power supply pins’ point of entry to the PC board to ensure the integrity of incoming supplies. The power-supply trace should lead directly from the tantalum capacitor to the VCC and VEE pins. To minimize parasitic inductance, keep PC traces short and use surface-mount components. Input termination resistors and output back-termination resistors, if used, should be surface-mount types, and should be placed as close to the IC pins as possible. DC and Noise Errors The MAX4104/MAX4105/MAX4304/MAX4305 output offset voltage, VOUT (Figure 1), can be calculated with the following equation: VOUT = [VOS + (IB+ x RS) + (IB- x (RF || RG))] [1 + RF / RG] where: VOS = input offset voltage (in volts) 1 + RF/RG = amplifier closed-loop gain (dimensionless) IB+ = noninverting input bias current (in amps) IB- = inverting input bias current (in amps) RG = gain-setting resistor (in ohms) RF = feedback resistor (in ohms) RS = source resistor at noninverting input (in ohms) The following equation represents output noise density: R en(OUT) = 1 + F RG (i n x RS ) 2 ( ) 2 2 + in x RF || RG + en _______________________________________________________________________________________ 9 MAX4104/MAX4105/MAX4304/MAX4305 _____________________Pin Description MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 RG RF RG RF IN- FB IB- OUT OUT VOUT 75Ω CABLE IB+ RT 75Ω IN+ IN MAX4104 MAX4105 MAX4304 MAX4305 RS 75Ω CABLE RL 75Ω MAX4104 MAX4105 MAX4304 MAX4305 RT 75Ω Figure 1. Output Offset Voltage Figure 2. Video Line Driver where: in = input current noise density (in pA/√Hz) en = input voltage noise density (in nV/√Hz) very rapidly during the conversion cycle—a condition that demands an amplifier with very low output impedance at high frequencies to maintain measurement accuracy. The combination of high-speed, fast slew rate, low noise, and low-distortion available in the MAX4104/MAX4105/MAX4304/MAX4305 makes them ideally suited for use as buffer amplifiers in high-speed ADC applications. The MAX4104/MAX4105/MAX4304/MAX4305 have a very low, 2.1nV/√Hz input voltage noise density and 3.1pA/√Hz input current noise density. An example of DC-error calculations, using the MAX4304 typical data and the typical operating circuit with RF = RG = 330Ω (RF || RG = 165Ω) and RS = 50Ω gives: [ ] VOUT = 32 x 10−6 50 + 32 x 10−6 165Ω + 1 x 10−3 1 + 1 ( ) ( ) VOUT = 15.8mV Calculating total output noise in a similar manner yields the following: Driving Capacitive Loads en(OUT) = [1+ 1] 2 2 3.1 x 10−12 x 50 + 3.1 x 10 −12 x 165 + 2.1 x 10 −9 2 en(OUT) = 4.3nV Hz With a 200MHz system bandwidth, this calculates to 60.8µVRMS (approximately 365µVp-p, using the sixsigma calculation). ADC Input Buffers Input buffer amplifiers can be a source of significant error in high-speed ADC applications. The input buffer is usually required to rapidly charge and discharge the ADC’s input, which is often capacitive. In addition, the input impedance of a high-speed ADC often changes 10 Video Line Driver The MAX4104/MAX4105/MAX4304/MAX4305 are optimized to drive coaxial transmission lines when the cable is terminated at both ends, as shown in Figure 2. To minimize reflections and maximize power transfer, select the termination resistors to match the characteristic impedance of the transmission line. Cable frequency response can cause variations in the flatness of the signal. The MAX4104/MAX4105/MAX4304/MAX4305 provide maximum AC performance when driving no output load capacitance. This is the case when driving a correctly terminated transmission line (i.e., a back-terminated cable). In most amplifier circuits, driving a large load capacitance increases the chance of oscillations occurring. The amplifier’s output impedance and the load capacitor combine to add a pole and excess phase to the loop response. If the pole’s frequency is low enough and phase margin is degraded sufficiently, oscillations may result. A second concern when driving capacitive loads originates from the amplifier’s output impedance, which ______________________________________________________________________________________ 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 25 25 CL = 15pF GAIN (dB) 15 CL = 10pF 10 5 0 -5 CL = 5pF CL = 15pF 20 NORMALIZED GAIN (dB) 20 15 CL = 10pF 10 5 0 -5 -10 -10 -15 -15 CL = 5pF -20 -20 100k 1M 10M 100M 100k 1G 1M 10M 100M 1G FREQUENCY (Hz) FREQUENCY (Hz) Figure 3a. MAX4104 Frequency Response with Capacitive Load and No Isolation Resistor Figure 3b. MAX4304 Frequency Response with Capacitive Load and No Isolation Resistor 25 25 20 20 CL = 15pF 10 CL = 10pF 5 0 -5 CL = 5pF -10 15 NORMALIZED GAIN (dB) 15 NORMALIZED GAIN (dB) MAX4104/MAX4105/MAX4304/MAX4305 30 30 CL = 15pF 10 CL = 10pF 5 0 -5 -10 -15 -15 -20 -20 CL = 5pF -25 -25 100k 1M 10M 100M 1G FREQUENCY (Hz) 100k 1M 10M 100M 1G FREQUENCY (Hz) Figure 3c. MAX4105 Frequency Response with Capacitive Load and No Isolation Resistor Figure 3d. MAX4305 Frequency Response with Capacitive Load and No Isolation Resistor appears 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 phase margin. The MAX4104/MAX4105/MAX4304/MAX4305 drive capacitive loads up to 10pF without oscillation. However, some peaking may occur in the frequency domain (Figure 3). To drive larger capacitance loads or to reduce ringing, add an isolation resistor between the amplifier’s output and the load (Figure 4). The value of RISO depends on the circuit’s gain and the capacitive load (Figure 5). Figure 6 shows the MAX4104/MAX4105/MAX4304/MAX4305 frequency response with the isolation resistor and a capacitive load. With higher capacitive values, bandwidth is dominated by the RC network formed by RISO and CL; the bandwidth of the amplifier itself is much higher. Also note that the isolation resistor forms a divider that decreases the voltage delivered to the load. Maxim’s High-Speed Evaluation Boards The MAX4104 evaluation kit manual shows a suggested layout for Maxim’s high-speed, single-amplifier evaluation boards. This board was developed using the techniques described previously ( see Layout and Power-Supply Bypassing section). The smallest available surface-mount resistors were used for the feedback and back-termination resistors to minimize the ______________________________________________________________________________________ 11 4 RF RG 3 2 CL = 47pF 1 GAIN (dB) MAX4104 MAX4105 MAX4304 MAX4305 IN- CL = 68pF 0 -1 -2 CL = 83pF -3 RISO OUT -4 CL IN+ -5 RL MAX4104/MAX4304 RISO = 15Ω -6 100k 1M 10M 100M 1G FREQUENCY (Hz) Figure 4. Using an Isolation Resistor (RISO) for High Capacitive Loads Figure 6. Frequency Responses vs. Capacitive Load with 15Ω Isolation Resistor distance from the IC to these resistors, thus reducing the capacitance associated with longer lead lengths. 30 OPTIMAL ISLOATION RESISTOR (Ω) MAX4104/MAX4105/MAX4304/MAX4305 740MHz, Low-Noise, Low-Distortion Op Amps in SOT23-5 SMA connectors were used for best high-frequency performance. Because distances are extremely short, performance is unaffected by the fact that inputs and outputs do not match a 50Ω line. However, in applications that require lead lengths greater than 1/4 of the wavelength of the highest frequency of interest, constant-impedance traces should be used. Fully assembled evaluation boards are available for the MAX4104 in an 8-pin SO package. 25 MAX4105/MAX4305 20 15 10 MAX4104/MAX4304 5 0 0 50 100 150 200 250 Ordering Information (continued) CAPACITIVE LOAD (pF) Figure 5. Optimal Isolation Resistor (RISO) vs. Capacitive Load Pin Configurations (continued) TOP VIEW N.C. 1 8 N.C. IN- 2 7 VCC IN+ 3 6 OUT 5 N.C. VEE 4 MAX4104 MAX4105 MAX4304 MAX4305 PART TEMP. RANGE PINPACKAGE SOT TOP MARK MAX4105ESA MAX4105EUK-T MAX4304ESA -40°C to +85°C -40°C to +85°C -40°C to +85°C 8 SO 5 SOT23-5 8 SO — ACCP — MAX4304EUK-T MAX4305ESA* MAX4305EUK-T -40°C to +85°C -40°C to +85°C -40°C to +85°C 5 SOT23-5 8 SO 5 SOT23-5 ACCQ — ACCR *Future product—contact factory for availability. Chip Information TRANSISTOR COUNT: 44 SUBSTRATE CONNECTED TO VEE SO 12 ______________________________________________________________________________________