19-0436; Rev 1; 3/96 KIT ATION EVALU E L B A IL AVA 500MHz, Low-Power Op Amps ____________________________Features The MAX4100/MAX4101 op amps combine ultra-highspeed performance with low-power operation. The MAX4100 is compensated for unity-gain stability, while the MAX4101 is compensated for stability in applications with a closed-loop gain (AVCL) of 2V/V or greater. The MAX4100/MAX4101 require only 5mA of supply current while delivering a 500MHz unity-gain bandwidth (MAX4100) or a 200MHz -3dB bandwidth (MAX4101) with a 250V/µs slew rate. ♦ 500MHz Unity-Gain Bandwidth (MAX4100) 200MHz -3dB Bandwidth (AVCL = 2V/V, MAX4101) These high-speed op amps have a wide output voltage swing of ±3.5V and a high current-drive capability of 80mA. ________________________Applications Video Cable Driver ♦ 65MHz 0.1dB Gain Flatness (MAX4100) ♦ 250V/µs Slew Rate ♦ 0.06%/0.04° Differential Gain/Phase ♦ High Output Drive: 80mA ♦ Low Power: 5mA Supply Current ♦ Fast Settling Time: 18ns to 0.1% 35ns to 0.01% ______________Ordering Information PART TEMP. RANGE PIN-PACKAGE Ultrasound MAX4100ESA -40°C to +85°C 8 SO Gamma Cameras MAX4100EUA -40°C to +85°C 8 µMAX* MAX4101ESA -40°C to +85°C 8 SO Portable Instruments * Contact factory for availability of µMAX package. Active Filters ADC Buffers ________Typical Application Circuit __________________Pin Configuration +5V TOP VIEW 0.1µF 1000pF INPUT 75Ω MAX4100 MAX4101 75Ω IN- 2 75Ω 0.1µF 1000pF IN+ 3 MAX4100 MAX4101 8 N.C. 7 VCC 6 OUT 5 N.C. 75Ω -5V 390Ω N.C. 1 VEE 4 75Ω SO/µMAX* 390Ω 75Ω VIDEO/RF DISTRIBUTION AMPLIFIER * Contact factory for availability of MAX4100 µMAX package. ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 MAX4100/MAX4101 _______________General Description MAX4100/MAX4101 500MHz, Low-Power Op Amps ABSOLUTE MAXIMUM RATINGS Power-Supply Voltage (VCC, VEE) .........................................±6V Voltage on Any Pin to Ground or Any Other Pin .........VCC to VEE Short-Circuit Duration (VOUT to GND) ...........................Indefinite Continuous Power Dissipation (TA = +70°C) SO (derate 5.88mW/°C above +70°C) .........................471mW µMAX (derate 4.10mW/°C above +70°C) ....................330mW Operating Temperature Ranges MAX4100E_A/MAX4101E_A ............................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°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. ELECTRICAL CHARACTERISTICS (VCC = 5V, VEE = -5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 8 mV DC SPECIFICATIONS Input Offset Voltage Input Offset Voltage Drift Input Bias Current Input Offset Current VOS VOUT = 0V 1 TCVOS VOUT = 0V 15 IB VOUT = 0V, VIN = -VOS 3 9 µV/°C µA IOS VOUT = 0V, VIN = -VOS 0.05 0.5 µA Common-Mode Input Resistance RINCM Either input 5 MΩ Common-Mode Input Capacitance CINCM Either input 1 pF Input Voltage Noise en Integrated Voltage Noise Input Current Noise f = 100kHz f = 1MHz to 100MHz in Integrated Current Noise f = 100kHz f = 1MHz to 100MHz Common-Mode Input Voltage VCM Common-Mode Rejection CMR VCM = ±2.5V Power-Supply Rejection PSR VS = ±4.5V to ±5.5V 100 MAX4101 75 MAX4100 0.8 MAX4101 0.8 MAX4100 10 MAX4101 10 nARMS V dB dB 51 56 RL = ∞ ±3.5 ±3.8 RL = 100Ω ±3.1 ±3.5 Short to ground or either supply voltage pA/√Hz 2.5 RL = 100Ω RL = 30Ω, TA = 0°C to +85°C ISC µVRMS 90 58 VIN = 0V nV/√Hz 75 60 ISY 2 MAX4100 53 Quiescent Supply Current Short-Circuit Output Current 6 55 VOUT = ±2.0V, VCM = 0V Output Current MAX4101 RL = ∞ AOL VOUT 8 -2.5 Open-Loop Voltage Gain Output Voltage Swing MAX4100 5 65 dB 6 mA V 80 mA 90 mA _______________________________________________________________________________________ 500MHz, Low-Power Op Amps (VCC = 5V, VEE = -5V, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS AC SPECIFICATIONS -3dB Bandwidth BW 0.1dB Bandwidth Slew Rate SR Settling Time VOUT ≤ 0.1VRMS 200 65 MAX4100, AVCL = +2 50 -2V ≤ VOUT ≤ 2V 18 to 0.01% 35 13 10% to 90%, -50mV ≤ VOUT ≤ 50mV, RL = 100Ω 1.5 tR, tF Differential Gain DG f = 3.58MHz Differential Phase DP f = 3.58MHz Input Capacitance CIN MHz MHz 250 to 0.1% 10% to 90%, -2V ≤ VOUT ≤ 2V, RL = 100Ω Rise/Fall Times MAX4100, AVCL = +1 0.06 MAX4101, AVCL = +2 0.07 MAX4100, AVCL = +1 0.04 MAX4101, AVCL = +2 0.04 MAX4100, AVCL = +1 0.8 MAX4101, AVCL = +2 0.3 MAX4100, AVCL = +1 -70 MAX4101, AVCL = +2 -65 V/µs ns ns % degrees 2 Output Resistance ROUT f = 10MHz Spurious-Free Dynamic Range SFDR fC = 5MHz, VOUT = 2Vp-p Third-Order Intercept 500 MAX4101 MAX4100, AVCL = +1 -1V ≤ VOUT ≤ 1V, RL = 100Ω ts MAX4100 fC = 10MHz, AVCL = +2 36 pF Ω dBc dBm __________________________________________Typical Operating Characteristics (VCC = 5V, VEE = -5V, TA = +25°C, unless otherwise noted.) CURRENT NOISE vs. FREQUENCY VOLTAGE NOISE vs. FREQUENCY 40 30 20 7 6 5 MAX4100 4 MAX4100-03 MAX4100-02 8 VOLTAGE (500mV/div) MAX4100 50 9 CURRENT NOISE (pA/√Hz) 60 VOLTAGE NOISE (nV/√Hz) 10 MAX4100-01 70 MAX4100 LARGE-SIGNAL PULSE RESPONSE (AVCL = +1) 3 IN GND OUT GND 2 10 MAX4101 1 MAX4101 0 0 10 100 1k 10k FREQUENCY (Hz) 100k 1M 10 100 1k 10k 100k 1M TIME (10ns/div) FREQUENCY (Hz) _______________________________________________________________________________________ 3 MAX4100/MAX4101 ELECTRICAL CHARACTERISTICS (continued) ____________________________Typical Operating Characteristics (continued) (VCC = 5V, VEE = -5V, TA = +25°C, unless otherwise noted.) MAX4100 LARGE-SIGNAL PULSE RESPONSE (AVCL = +5) MAX4100-05 100 VOLTAGE (20mV/div) GND OUT RESISTANCE (Ω) 10 MAX4100-06 MAX4100-04 VOLTAGE (500mV/div) MAX4100 SMALL-SIGNAL PULSE RESPONSE (AVCL = +1) MAX4100 OUTPUT RESISTANCE vs. FREQUENCY GND IN 1.0 0.1 IN GND OUT GND 0.01 10k TIME (20ns/div) 100k 1M 10M 100M 1G TIME (10ns/div) FREQUENCY (Hz) MAX4100 SMALL-SIGNAL PULSE RESPONSE (AVCL = +5) MAX4101 LARGE-SIGNAL PULSE RESPONSE (AVCL = +2) MAX4100-08 100 VOLTAGE (500mV/div) GND GND RESISTANCE (Ω) VOLTAGE (10mV/div) 10 OUT MAX4100-09 MAX4101 OUTPUT RESISTANCE vs. FREQUENCY MAX4100-07 IN 1.0 IN GND OUT GND 0.1 0.01 10k TIME (50ns/div) 100k 1M 10M 100M 1G TIME (10ns/div) FREQUENCY (Hz) MAX4101 SMALL-SIGNAL PULSE RESPONSE (AVCL = +2) GND TIME (20ns/div) 4 VOLTAGE (10mV/div) OUT MAX4100-11b IN GND IN OUT GND TIME (10ns/div) VOLTAGE (10mV/div) MAX4100-10 IN MAX4101 SMALL-SIGNAL PULSE RESPONSE (AVCL = +10) MAX4100-11a MAX4101 LARGE-SIGNAL PULSE RESPONSE (AVCL = +10) VOLTAGE (500mV/div) MAX4100/MAX4101 500MHz, Low-Power Op Amps OUT GND TIME (50ns/div) _______________________________________________________________________________________ 500MHz, Low-Power Op Amps INPUT BIAS CURRENT vs. TEMPERATURE 0.5 6 -1.0 -1.5 0.15 CURRENT (µA) -0.5 4 3 -2.0 -2.5 -3.0 25 0 50 0.05 -0.05 2 -0.15 1 -0.25 0 -75 -50 -25 -0.35 -75 -50 -25 75 100 125 0 25 50 75 100 125 -75 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) TEMPERATURE (°C) TEMPERATURE (°C) POWER-SUPPLY CURRENT vs. TEMPERATURE MAX4100 COMMON-MODE REJECTION vs. FREQUENCY MAX4100 POWER-SUPPLY REJECTION vs. FREQUENCY 70 60 60 50 40 50 40 PSR30 30 4 70 PSR (dB) CMR (dB) 5 20 20 10 10 PSR+ 0 3 0 25 50 75 100 125 30k 100k TEMPERATURE (°C) 1M 100M 10M 3 RL = 100Ω 2 -2 RL = 100Ω -3 -4 RL = ∞ -5 100M 1G MAX4100-17 RL = ∞ 10M FREQUENCY (Hz) 3.5 3.0 OUTPUT SWING (Vp-p) 4 1M OUTPUT SWING vs. LOAD RESISTANCE MAX4100 TOC-20A 6 5 0 0.1M 1G FREQUENCY (Hz) POSITIVE OUTPUT SWING vs. TEMPERATURE POSITIVE OUTPUT SWING (V) -75 -50 -25 MAX4100 TOC-16 80 6 80 MAX4100 TOC-15 90 MAX4100 TOC-13 7 CURRENT (mA) 0.25 5 CURRENT (µA) VOLTAGE (mV) 0 0.35 MAX4100 TOC-14A 7 MAX4100 TOC-12 1.0 INPUT OFFSET CURRENT vs. TEMPERATURE MAX4100 TOC-14B INPUT OFFSET VOLTAGE vs. TEMPERATURE 2.5 2.0 1.5 1.0 0.5 -6 0 -75 -50 -25 0 25 50 75 100 125 TEMPERATURE (°C) 10 22 33 50 75 LOAD RESISTANCE (Ω) _______________________________________________________________________________________ 5 MAX4100/MAX4101 ____________________________Typical Operating Characteristics (continued) (VCC = 5V, VEE = -5V, TA = +25°C, unless otherwise noted.) ____________________________Typical Operating Characteristics (continued) (VCC = 5V, VEE = -5V, TA = +25°C, unless otherwise noted.) MAX4101 OPEN-LOOP GAIN AND PHASE vs. FREQUENCY 90 20 PHASE 10 135 0 100k 1M 10M 100M MAX4100-19 10 0 -1 -2 -3 -4 135 -5 -6 180 10k 1G 100k 1M 10M 100M -7 1G 0.1M 10M 1M 100M 1G FREQUENCY (Hz) MAX4101 CLOSED-LOOP RESPONSE (AVCL = +2) MAX4100 HARMONIC DISTORTION vs. FREQUENCY MAX4100 HARMONIC DISTORTION vs. FREQUENCY 6 5 4 3 2 1 0 -10 GAIN = +1 VO = 2Vp-p RL = 100Ω -20 -30 -40 2nd HARMONIC -50 -60 -70 3rd HARMONIC -80 -1 0 HARMONIC DISTORTION (dBc) 7 0 HARMONIC DISTORTION (dBc) MAX4100 TOC-23 9 10M 1M 100M 1G GAIN = +2 VO = 2Vp-p RL = 100Ω -20 -30 -40 -50 2nd HARMONIC -60 -70 3rd HARMONIC -80 -90 -90 0.1M -10 MAX4100 TOC-25 FREQUENCY (Hz) MAX4100 TOC-24 FREQUENCY (Hz) 8 0.1 1 10 0.1 100 1 10 100 FREQUENCY (MHz) MAX4100 HARMONIC DISTORTION vs. FREQUENCY MAX4101 HARMONIC DISTORTION vs. FREQUENCY MAX4101 HARMONIC DISTORTION vs. FREQUENCY -30 -40 -50 2nd HARMONIC -60 3rd HARMONIC -70 -10 -20 -30 -40 -50 -60 3rd HARMONIC -80 -90 -90 1 10 FREQUENCY (MHz) 100 2nd HARMONIC -70 -80 0.1 GAIN = +2 VO = 2Vp-p RL = 100Ω 0 HARMONIC DISTORTION (dBc) -20 0 HARMONIC DISTORTION (dBc) GAIN = +5 VO = 2Vp-p RL = 100Ω -10 MAX4100 TOC-28 FREQUENCY (MHz) MAX4100 TOC-26 FREQUENCY (Hz) MAX4100 TOC-27 GAIN (dB) PHASE -20 180 10k 6 90 20 1 -10 -20 -10 30 0 -10 0 45 GAIN 2 GAIN (dB) 30 3 0 40 LOOP GAIN (dB) 45 GAIN PHASE (DEGREES) MAX4100-18 40 LOOP GAIN (dB) 60 50 0 PHASE (DEGREES) 60 50 MAX4100 CLOSED-LOOP RESPONSE (AVCL = +1) MAX4100 TOC-22 MAX4100 OPEN-LOOP GAIN AND PHASE vs. FREQUENCY HARMONIC DISTORTION (dBc) MAX4100/MAX4101 500MHz, Low-Power Op Amps GAIN = +5 VO = 2Vp-p RL = 100Ω -20 -30 -40 -50 2nd HARMONIC -60 3rd HARMONIC -70 -80 -90 0.1 1 10 FREQUENCY (MHz) 100 0.1 1 10 FREQUENCY (MHz) _______________________________________________________________________________________ 100 500MHz, Low-Power Op Amps TWO-TONE THIRD-ORDER INTERCEPT vs. FREQUENCY -20 -30 -40 -50 2nd HARMONIC -60 3rd HARMONIC -70 40 -80 0.1 1 20 25 20 15 10 5 0.1 100 10 1 10 FREQUENCY (MHz) MAX4100 DIFFERENTIAL GAIN AND PHASE MAX4101 DIFFERENTIAL GAIN AND PHASE 0 0.02 -0.00 -0.02 -0.04 -0.06 -0.08 -0.10 100 0 DIFF PHASE (deg) 0.05 0.04 0.03 0.02 0.01 0.00 -0.01 0 100 MAX4100-32 0.02 -0.00 -0.02 -0.04 -0.06 -0.08 DIFF GAIN (%) FREQUENCY (MHz) MAX4100-31 DIFF GAIN (%) 35 0 -90 DIFF PHASE (deg) MAX4100-30 GAIN = +10 VO = 2Vp-p RL = 100Ω -10 THIRD-ORDER INTERCEPT (dBm) HARMONIC DISTORTION (dBc) 0 MAX4100 TOC-29 MAX4101 HARMONIC DISTORTION vs. FREQUENCY 100 0.06 0.04 0.02 0.00 -0.02 100 0 IRE 100 IRE ______________________________________________________________Pin Description PIN NAME FUNCTION 1, 5, 8 N.C. 2 IN- Inverting Input 3 IN+ Noninverting Input 4 VEE Negative Power Supply, connected to -5V 6 OUT Amplifier Output 7 VCC Positive Power Supply, connected to +5V No Connection, not internally connected _______________________________________________________________________________________ 7 MAX4100/MAX4101 ____________________________Typical Operating Characteristics (continued) (VCC = 5V, VEE = -5V, TA = +25°C, unless otherwise noted.) MAX4100/MAX4101 500MHz, Low-Power Op Amps _______________Detailed Description The MAX4100/MAX4101 are low-power, high-bandwidth operational amplifiers optimized for driving back-terminated cables in composite video, RGB, and RF systems. The MAX4100 is unity-gain stable, and the MAX4101 is optimized for closed-loop gains greater than or equal to 2V/V (AVCL ≥ 2V/V). While consuming only 5mA (6mA max) supply current, both devices can drive 50Ω backterminated cables to ±3.1V minimum. The MAX4100 features a bandwidth in excess of 500MHz and a 0.1dB gain flatness of 65MHz. It offers differential gain and phase errors of 0.06%/0.04°, respectively. The MAX4101 features a -3dB bandwidth of 200MHz, a 0.1dB bandwidth of 50MHz, and 0.07%/0.04° differential gain and phase. Available in small 8-pin SO and µMAX packages, these ICs are ideally suited for use in portable systems (in RGB, broadcast, or consumer video applications) that benefit from low power consumption. __________Applications Information Layout and Power-Supply Bypassing The MAX4100/MAX4101 have an RF bandwidth and, consequently, require careful board layout. Depending on the size of the PC board used and the frequency of operation, it may be desirable to use constant-impedance microstrip or stripline techniques. To realize the full AC performance of this high-speed amplifier, 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 a constant-impedance board is used, it is best to observe the following guidelines when designing the board. Wire-wrap boards are much too inductive, and breadboards are much too capacitive; neither should be used. IC sockets increase parasitic capacitance and inductance, and should not be used. In general, surface-mount components give better high-frequency performance than through-hole components. They have shorter leads and lower parasitic reactances. Keep lines as short and as straight as possible. Do not make 90° turns; round all corners. High-frequency bypassing techniques must be observed to maintain the amplifier accuracy. The bypass capacitors should include a 1000pF ceramic capacitor between each supply pin and the ground plane, located as close to the package as possible. Next, place a 0.01µF to 0.1µF ceramic capacitor in parallel with each 1000pF capacitor, and as close to each as possible. Then place a 10µF to 15µF low-ESR tantalum at the point of entry (to the PC board) of the power-supply pins. 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. RG RF MAX4100 MAX4100 MAX4101 MAX4101 VOUT VIN VOUT = [1 + (RF / RG)]VIN Figure 1b. Noninverting Gain Configuration VIN RG RF MAX4100 MAX4100 MAX4101 MAX4101 24Ω VOUT MAX4100 MAX4100 MAX4101 MAX4101 VIN VOUT = (RF / RG)VIN Figure 1a. Inverting Gain Configuration 8 VOUT = VIN Figure 1c. MAX4100 Unity-Gain Buffer Configuration _______________________________________________________________________________________ VOUT 500MHz, Low-Power Op Amps RG Table 1. Resistor and Bandwidth Values for Various Gain Configurations RF C MAX4100 MAX4100 MAX4101 VOUT Figure 2. Effect of Feedback Resistor Values and Parasitic Capacitance on Bandwidth Setting Gain The MAX4100/MAX4101 are voltage-feedback op amps that can be configured as an inverting or noninverting gain block, as shown in Figures 1a and 1b. The gain is determined by the ratio of two resistors and does not affect amplifier frequency compensation. In the unity-gain configuration (as shown in Figure 1c), maximum bandwidth and stability is achieved with the MAX4100 when a small feedback resistor is included. This resistor suppresses the negative effects of parasitic inductance and capacitance. A value of 24Ω provides the best combination of wide bandwidth, low peaking, and fast settling time. In addition, this resistor reduces the errors from input bias currents. Choosing Resistor Values The values of feedback and input resistors used in the inverting or noninverting gain configurations are not critical (as is the case with current feedback amplifiers). However, take care when selecting because the ohmic values need to be kept small and noninductive for practical reasons. The input capacitance of the MAX4100/MAX4101 is approximately 2pF. In either the inverting or noninverting configuration, the bandwidth limit caused by the package capacitance and resistor time constant is f3dB = 1 / (2Π RC), where R is the parallel combination of the input and feedback resistors (R F and R G in Figure 2) and C is the package and board capacitance at the inverting input. Table 1 shows the bandwidth limit for several values of RF and RG, assuming 4pF total capacitance (2pF for the MAX4100/MAX4101 and 2pF of PC board parasitics). GAIN (V/V) RG (Ω) RF (Ω) BANDWIDTH LIMIT* (MHz) +1 ∞ 24 1659 +2 200 200 398 +5 50 200 995 +10 30 270 1474 -1 200 200 398 -2 75 150 796 -5 50 250 955 -10 50 500 875 * Assuming an infinite bandwidth amplifier. Resistor Types Surface-mount resistors are the best choice for highfrequency circuits. They are of similar material to the metal film resistors, but are deposited using a thick-film process in a flat, linear manner so that inductance is minimized. Their small size and lack of leads also minimize parasitic inductance and capacitance, thereby yielding more predictable performance. DC and Noise Errors There are several major error sources to be considered in any operational amplifier. These apply equally to the MAX4100/MAX4101. Offset-error terms are given by the equation below. Voltage and current noise errors are root-square summed, so are computed separately. Using the circuit in Figure 3, the total output offset voltage is determined by: a) The input offset voltage (VOS) times the closed-loop gain (1 + RF / RG) b) The positive input bias current (I B+ ) times the source resistor (RS) minus the negative input bias current (IB-) times the parallel combination of RG and R F . I OS (offset current) is the difference between the two bias currents. If RG | | RF = RS, this part of the expression becomes IOS x RS. The equation for total DC error is: R VOUT = IOSRS + VOS 1 + F RG ( ) _______________________________________________________________________________________ 9 MAX4100/MAX4101 VIN In both DC and noise calculations, errors are dominated by offset voltage and noise voltage (rather than by input bias current or noise current). Metal-film resistors with leads are manufactured using a thin-film process, where resistive material is deposited in a spiral layer around a ceramic rod. Although the materials used are noninductive, the spiral winding presents a small inductance (about 5nH) that may have an adverse effect on high-frequency circuits. RF IB- RS IB+ VOUT MAX4100 MAX4100 MAX4101 10 Figure 3. Output Offset Voltage c) Total output-referred noise voltage is shown by the equation below (en(OUT)): (2inRS )2 + (eN )2 4 2 0 -2 CL = 5pF -4 CL = 0pF -6 -10 0.1M 1M 10M 100M 1G FREQUENCY (Hz) Figure 4a. MAX4100 Bandwidth vs. Capacitive Load R VOUT = IOSRS + VOS 1 + F RG ) 10 ( ) VOUT = 3 × 10 −6 × 102 + 1 × 10 −3 1 + 1 Calculating total output-referred noise in a similar manner yields: 2 en(OUT) = 1 + 1 2 × 0.8 × 10 −12 × 100 + 8 × 10 −9 CL = 10pF 8 VOUT = 2.6mV ( ) CL = 10pF -8 The MAX4100/MAX4101, with two high-impedance inputs, have low 8nV√Hz voltage noise and only 0.8pA√Hz current noise. An example of DC error calculations, using the MAX4100/MAX4101 typical data and the typical operating circuit with RF = RG = 200Ω (RS = 100Ω), gives: ( RS = 0Ω 6 2 en(OUT) = 8nV / Hz 6 4 2 0 -2 -4 RS = 22Ω RS = 10Ω RS = 4.7Ω RS = 2.2Ω -6 -8 -10 0.1M With a 200MHz system bandwidth, this calculates to 133µVRMS (approximately 679µVp-p). MAX4100-4b R en(OUT) = 1 + F RG CLOSED-LOOP GAIN (dB) 8 MAX4100-4a RI CLOSED-LOOP GAIN (dB) MAX4100/MAX4101 500MHz, Low-Power Op Amps 1M 10M 100M 1G FREQUENCY (Hz) Figure 4b. MAX4100 Bandwidth vs. Capacitive Load and Isolation Resistor 10 ______________________________________________________________________________________ 500MHz, Low-Power Op Amps MAX4100/MAX4101 Carbon composition resistors with leads are manufactured by pouring the resistor material into a mold. This process yields a relatively low-inductance resistor that is very useful in high-frequency applications, although they tend to cost more and have more thermal noise than other types. The ability of carbon composition resistors to self-heal after a large current overload makes them useful in high-power RF applications. For general-purpose use, surface-mount metal-film resistors seem to have the best overall performance for low cost, low inductance, and low noise. 24Ω RS MAX4100 VIN RL CL Driving Capacitive Loads Figure 5a. Using an Isolation Resistor for High Capacitive Loads (MAX4100) MAX4100 FIG05 25 DECOUPLING RESISTOR (Ω) When driving 50Ω or 75Ω back-terminated transmission lines, capacitive loading is not an issue; therefore an isolation resistor is not required. For other applications where the ability to drive capacitive loads is required, the MAX4100/MAX4101 can typically drive 5pF and 20pF, respectively. Figure 4a illustrates how a capacitive load influences the amplifier’s peaking without an isolation resistor (RS). Figure 4b shows how an isolation resistor decreases the amplifier’s peaking. The MAX4100/MAX4101 can drive capacitive loads up to 5pF. By using a small isolation resistor between the amplifier output and the load, large capacitance values may be driven without oscillation (Figure 5a). In most cases, less than 50Ω is sufficient. Use Figure 5b to determine the value needed in your application. Determine the worst-case maximum capacitive load you may encounter and select the appropriate resistor from the graph. 20 MAX4100 15 10 MAX4101 5 0 0 20 40 60 80 100 120 CAPACITIVE LOAD (pF) Figure 5b. Isolation vs. Capacitive Load ______________________________________________________________________________________ 11 MAX4100/MAX4101 500MHz, Low-Power Op Amps ________________________________________________________Package Information DIM D 0°-8° A 0.101mm 0.004in. e B A1 E C L Narrow SO SMALL-OUTLINE PACKAGE (0.150 in.) H A A1 B C E e H L INCHES MAX MIN 0.069 0.053 0.010 0.004 0.019 0.014 0.010 0.007 0.157 0.150 0.050 0.244 0.228 0.050 0.016 DIM PINS D D D 8 14 16 MILLIMETERS MIN MAX 1.35 1.75 0.10 0.25 0.35 0.49 0.19 0.25 3.80 4.00 1.27 5.80 6.20 0.40 1.27 INCHES MILLIMETERS MIN MAX MIN MAX 0.189 0.197 4.80 5.00 0.337 0.344 8.55 8.75 0.386 0.394 9.80 10.00 21-0041A 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 © 1995 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.