19-2103; Rev 0; 8/01 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps The LMX321/LMX358/LMX324 are single/dual/quad, low-cost, low-voltage, pin-to-pin compatible upgrades to the LMV321/LMV358/LMV324 family of general purpose op amps. These devices offer Rail-to-Rail® outputs and an input common-mode range that extends below ground. These op amps draw only 105µA of quiescent current per amplifier, operate from a single +2.3V to +7V supply, and drive 2kΩ resistive loads to within 40mV of either rail. The LMX321/LMX358/LMX324 are unity-gain stable with a 1.3MHz gain-bandwidth product capable of driving capacitive loads up to 400pF. The combination of low voltage, low cost, and small package size makes these amplifiers ideal for portable/battery-powered equipment. The LMX321 single op amp is available in ultra-small 5pin SC70 and space-saving 5-pin SOT23 packages. The LMX358 dual op amp is available in the tiny 8-pin SOT23 package. The LMX324 quad op amp is available in 14-pin TSSOP and SO packages. Features ♦ Upgrade to LMV321/LMV358/LMV324 Family ♦ Single +2.3V to +7V Supply Voltage Range ♦ Available in Space-Saving Packages 5-Pin SC70 (LMX321) 8-Pin SOT23 (LMX358) 14-Pin TSSOP (LMX324) ♦ 1.3MHz Gain-Bandwidth Product ♦ 105µA Quiescent Current per Amplifier (VCC = +2.7V) ♦ No Phase Reversal for Overdriven Inputs ♦ No Crossover Distortion ♦ Rail-to-Rail Output Swing ♦ Input Common-Mode Voltage Range: VEE - 0.2V to VCC - 0.8V ♦ Drives 2kΩ Resistive Loads Ordering Information Applications Cellular Phones PART TEMP. RANGE PIN-PACKAGE -40°C to +125°C 5 SC70-5 Laptops LMX321AXK-T Low-Power, Low-Voltage Applications LMX321AUK-T -40°C to +125°C 5 SOT23-5 Portable/Battery-Powered Equipment LMX358AKA-T -40°C to +125°C 8 SOT23-8 LMX358ASA -40°C to +125°C 8 SO LMX358AUA -40°C to +125°C 8 µMAX LMX324ASD -40°C to +125°C 14 SO LMX324AUD -40°C to +125°C 14 TSSOP Cordless Phones Active Filters Selector Guide appears at end of data sheet. Pin Configurations TOP VIEW OUT1 1 IN+ 1 LMX321 LMX358 5 VCC 8 VCC 7 OUT2 IN1- 2 VEE 2 IN1+ 3 6 IN2- VEE 4 5 IN2+ OUT1 1 14 OUT4 IN1- 2 13 IN4- IN1+ 3 12 IN4+ VCC 4 LMX324 11 VEE IN2+ 5 10 IN3+ IN2- 6 9 IN3- OUT2 7 8 OUT3 4 OUT IN- 3 SC70-5/SOT23-5 SOT23-8/SO/µMAX TSSOP/SO Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 LMX321/LMX358/LMX324 General Description LMX321/LMX358/LMX324 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps ABSOLUTE MAXIMUM RATINGS Supply Voltage (VCC to VEE) ....................................-0.3V to +8V Differential Input Voltage (VIN+ - VIN-) ........................VEE to VCC OUT_ to VEE ...............................................-0.3V to (VCC + 0.3V) Output Short-Circuit Duration OUT_ Shorted to VCC or VEE ..................................Continuous Continuous Power Dissipation (TA = +70°C) 5-Pin SC70-5 (derate 3.1mW/°C above +70°C)...........247mW 5-Pin SOT23-5 (derate 7.1mW/°C above +70°C) ........571mW 8-Pin SOT23-8 (derate 7.52mW/°C above +70°C) ......602mW 8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW 8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW 14-Pin TSSOP (derate 9.1mW/°C above +70°C) .........727mW 14-Pin SO (derate 8.3mW/°C above +70°C)................667mW Operating Temperature Range .........................-40°C to +125°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +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. ELECTRICAL CHARACTERISTICS (VCC = +2.7V, VEE = 0, VOUT = VCC/2, VCM = 1V, RL > 1MΩ, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VOS 1 6 mV TCVOS 6 IB 18 50 nA IOS 1 8 nA DC Characteristics Input Offset Voltage Input Offset Voltage Average Drift Input Bias Current Input Offset Current µV/oC Common-Mode Rejection Ratio CMRR -0.2V < VCM < 1.8V 72 92 dB Power-Supply Rejection Ratio PSRR 2.3V < VCC < 7V, VOUT = 1V 82 96 dB Input Common-Mode Voltage Range VCM For CMRR > 72dB Large-Signal Voltage Gain AVOL RL = 2kΩ to VEE, 0.3V < VOUT < 2.4V RL = 10kΩ to 1.35V Output Voltage Swing VOUT RL = 2kΩ to 1.35V LMX321 (Single) Supply Current ICC Limit -0.2 1.8 Typ -0.2 1.9 20 120 V/mV VCC - VOH 12 50 VOL 10 40 VCC - VOH 40 110 VOL V 25 60 105 150 LMX358 (Dual) 210 300 LMX324 (Quad) 420 600 mV µA AC Characteristics Slew Rate Gain-Bandwidth Product 2 SR GBW 1V step Input CL = 200pF 1 V/µs 1.3 MHz degrees Phase Margin φM Gain Margin GM 24 dB Input Noise Voltage Density en f = 1kHz 66 nV/√Hz Input Current Noise Density in f = 1kHz 0.13 pA/√Hz 64 _______________________________________________________________________________________ Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324 ELECTRICAL CHARACTERISTICS (VCC = +2.7V, VEE = 0, VOUT = VCC/2, VCM = 1V, RL > 1MΩ, TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VOS 9 mV IB 70 nA IOS 15 nA DC Characteristics Input Offset Voltage Input Bias Current Input Offset Current Common-Mode Rejection Ratio CMRR -0.1 < VCM < 1.7V Power-Supply Rejection Ratio PSRR 2.3V < VCC < 7V, VOUT = 1V 60 1.7 Typ -0.1 1.8 For CMRR > 60dB Large-Signal Voltage Gain AVOL RL = 2kΩ to VEE, 0.3V < VOUT < 2.4V RL = 10kΩ to 1.55V RL = 2kΩ to 1.35V Supply Current ICC dB -0.1 VCM VOUT 75 Limit Input Common-Mode Voltage Range Output Voltage Swing dB 10 V V/mV VCC - VOH 130 VOL 50 VCC - VOH 150 VOL 70 LMX321 (Single) 180 LMX358 (Dual) 360 LMX324 (Quad) 720 mV µA ELECTRICAL CHARACTERISTICS (VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1MΩ, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VOS 1 6 mV TCVOS 6 IB 18 50 nA IOS 1 8 nA DC Characteristics Input Offset Voltage Input Offset Voltage Average Drift Input Bias Current Input Offset Current µV/oC Common-Mode Rejection Ratio CMRR -0.2 < VCM < 4.1V 72 92 dB Power-Supply Rejection Ratio PSRR 2.3V < VCC < 7V, VOUT = 1V, VCM = 1V 82 96 dB Input Common-Mode Voltage Range VCM For CMRR > 72dB Large-Signal Voltage Gain AVOL RL = 2kΩ to VEE, 0.3V < VOUT < 4.7V Limit -0.2 4.1 Typ -0.2 4.2 40 200 V V/mV _______________________________________________________________________________________ 3 LMX321/LMX358/LMX324 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps ELECTRICAL CHARACTERISTICS (continued) (VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1MΩ, TA = +25°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS RL = 10kΩ to 2.5V Output Voltage Swing VOUT RL = 2kΩ to 2.5V Output Short-Circuit Current ISC Supply Current ICC MIN TYP MAX 60 VCC - VOH 20 VOL 12 40 VCC - VOH 65 130 40 80 VOL Sourcing, VOUT = 0 5 25 Sinking, VOUT = 5V 10 28 UNITS mV mA LMX321 (Single) 120 LMX358 (Dual) 240 170 340 LMX324 (Quad) 480 680 µA AC Characteristics Slew Rate Gain-Bandwidth Product SR GBW 3V step input CL = 200pF 1 V/µs 1.3 MHz degrees Phase Margin φM 65 Gain Margin GM 25 dB Input Noise Voltage Density en f = 1kHz 65 nV/√Hz Input Noise Current Density in f = 1kHz 0.13 pA/√Hz ELECTRICAL CHARACTERISTICS (VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1MΩ, TA = -40°C to +125°C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS VOS 9 mV IB 70 nA IOS 15 nA DC Characteristics Input Offset Voltage Input Bias Current Input Offset Current Common-Mode Rejection Ratio CMRR -0.1 < VCM < 4.0V 63 Power-Supply Rejection Ratio PSRR 2.3V < VCC < 7V, VOUT = 1V, VCM = 1V 4.0 Typ -0.1 4.1 For CMRR > 63dB Large-Signal Voltage Gain AVOL RL = 2kΩ to VEE, 0.3V < VOUT < 4.7V RL = 10kΩ to 2.5V RL = 2kΩ to 2.5V Supply Current ICC dB -0.1 VCM VOUT 75 Limit Input Common-Mode Voltage Range Output Voltage Swing dB 20 V/mV VCC - VOH 170 VOL 70 VCC - VOH 190 VOL 210 LMX358 (Dual) 420 LMX324 (Quad) 840 _______________________________________________________________________________________ mV 90 LMX321 (Single) Note 1: Specifications are 100% tested at TA = +25°C (exceptions noted). All temperature limits are guaranteed by design. 4 V µA Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps 100 TA = +85°C TA = +25°C 40 TA = -40°C LMX321 toc02 -13 -14 -15 -16 VCC = +5V, VIN = VCC/2 -17 VCC = 2.7V 10 1 0.1 -19 -20 3 4 5 6 7 0.01 -40 -25 -10 5 20 35 50 65 80 95 110 125 0.01 10 SOURCE CURRENT vs. OUTPUT VOLTAGE SINK CURRENT vs. OUTPUT VOLTAGE SINK CURRENT vs. OUTPUT VOLTAGE LMX321 toc04 100 SINK CURRENT (mA) 10 1 0.1 VCC = 2.7V 100 10 1 0.1 0.01 0.1 1 VCC = 5V 10 1 0.1 0.01 0.001 10 LMX321 toc06 OUTPUT VOLTAGE REFERENCED TO VCC (V) VCC = 5V 0.01 0.1 1 0.01 0.001 10 0.01 0.1 1 OUTPUT VOLTAGE REFERENCED TO VEE (V) OUTPUT VOLTAGE REFERENCED TO VEE (V) OUTPUT VOLTAGE SWING vs. SUPPLY VOLTAGE OUTPUT VOLTAGE SWING vs. SUPPLY VOLTAGE INPUT VOLTAGE NOISE vs. FREQUENCY 80 POSITIVE SWING (VCC - VOH) 70 60 50 40 30 LMX321 toc08 90 35 RL = 10kΩ OUTPUT VOLTAGE SWING (mV) LMX321 toc07 RL = 2kΩ 30 POSITIVE SWING (VCC - VOH) 25 20 15 10 NEGATIVE SWING (VOL) NEGATIVE SWING (VOL) 5 20 3 4 5 SUPPLY VOLTAGE (V) 6 7 2 3 4 5 SUPPLY VOLTAGE (V) 6 7 INPUT VOLTAGE NOISE (nV/√Hz) OUTPUT VOLTAGE REFERENCED TO VCC (V) 100 2 1 TEMPERATURE (°C) 100 0.01 0.1 SUPPLY VOLTAGE (V) 600 550 500 450 400 350 300 250 200 150 100 50 0 10 VCC = 2.7V TO 5V, VCM = VCC/2 1 10 100 1k 10k LMX321 toc09 2 SINK CURRENT (mA) 1 LMX321 toc05 0 SOURCE CURRENT (mA) -12 -18 20 0 OUTPUT VOLTAGE SWING (mV) 100 SOURCE CURRENT (mA) 120 80 -11 INPUT BIAS CURRENT (nA) TA = +125°C 60 -10 LMX321 toc01 SUPPLY CURRENT PER AMPLIFIER (µA) 160 140 SOURCE CURRENT vs. OUTPUT VOLTAGE INPUT BIAS CURRENT vs. TEMPERATURE LMX321 toc03 SUPPLY CURRENT PER AMPLIFIER vs. SUPPLY VOLTAGE 100k FREQUENCY (Hz) _______________________________________________________________________________________ 5 LMX321/LMX358/LMX324 Typical Operating Characteristics (TA = +25°C, VEE = 0, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, VEE = 0, unless otherwise noted.) CROSSTALK REJECTION vs. FREQUENCY 2.0 1.5 1.0 -40 -90 -110 -100 -150 10 100 1k 10k 100k -120 100 1k 10k 100k 1M 10M 100 100M INPUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE INPUT OFFSET VOLTAGE vs. OUTPUT VOLTAGE 100 LMX321 toc14 VCC = 2.5V, VEE = -2.5V 0.10 -0.05 -0.10 0 -0.05 -0.10 -0.15 25 -0.7 -0.2 0.3 0 RL = 10kΩ -25 -50 -100 -3 -2.8 -2.3 -1.8 -1.3 -0.8 -0.3 0.2 0.7 1.2 1.7 2.2 0.8 RL = 2kΩ -75 -0.20 -1.2 RL = 600Ω 50 -0.15 -0.20 VCC = 2.5V, VEE = -2.5V 75 INPUT OFFSET VOLTAGE (µV) LMX321 toc13 0.15 ∆VOS (mV) 0 -2 -1 0 1 2 COMMON-MODE VOLTAGE (V) COMMON-MODE VOLTAGE (V) OUTPUT VOLTAGE (V) INPUT OFFSET VOLTAGE vs. OUTPUT VOLTAGE GAIN AND PHASE vs. FREQUENCY and RESISTIVE LOAD GAIN AND PHASE vs. FREQUENCY AND RESISTIVE LOAD 75 RL = 600Ω LMX321 toc17 50 40 50 GAIN (dB) 30 25 RL = 2kΩ 0 RL = 10kΩ 60 20 40 10 20 RL = 600kΩ 0 0 -50 -10 -75 -20 100 -1.0 -0.5 0 0.5 OUTPUT VOLTAGE (V) 1.0 1.5 VCC = 2.5V, VEE = -2.5V CL = 0, RL TO VEE AVCL = 60dB, VOUT = 0 RL = 100kΩ 10k 100k 1M FREQUENCY (Hz) 10M RL = 600Ω 40 80 RL = 100kΩ 3 LMX321 toc18 50 100 30 GAIN (dB) VCC = 1.35V, VEE = -1.35V LMX321 toc16 100 PHASE MARGIN (degrees) ∆VOS (mV) 1M INPUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE 0.05 6 100k FREQUENCY (Hz) 0.05 -1.5 10k FREQUENCY (Hz) VCC = 1.35V, VEE = -1.35V -25 1k FREQUENCY (Hz) 0.10 -1.7 PSRR+ -60 -80 -130 1 PSRR- -70 0.5 0 LMX321 toc12 VCC = 2.7V TO 5V -20 40 10 20 RL = 600Ω 0 0 -10 -40 -20 80 60 RL = 100kΩ 20 -20 100 VCC = 1.35V, VEE = -1.35V CL = 0, RL TO VEE AVCL = 60dB, VOUT = 0 RL = 100kΩ 10k 100k 1M FREQUENCY (Hz) _______________________________________________________________________________________ -20 -40 10M PHASE (degrees) 2.5 0 LMX321 toc15 3.0 VCC = 5V, RL = 5kΩ PSRR (dB) 3.5 -50 POWER-SUPPLY REJECTION RATIO vs. FREQUENCY LMX321 toc11 VCC = 2.7V TO 5V, VCM = VCC/2 CROSSTALK REJECTION (dB) INPUT CURRENT NOISE (pA/√Hz) 4.0 LMX321 toc10 INPUT CURRENT NOISE vs. FREQUENCY INPUT OFFSET VOLTAGE (mV) LMX321/LMX358/LMX324 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps GAIN AND PHASE vs. FREQUENCY AND CAPACTIVE LOAD GAIN AND PHASE vs. FREQUENCY AND CAPACITIVE LOAD 50 100 80 60 CL = 500pF 40 CL = 1nF 10 20 0 VCC = 2.5V, VEE = -2.5V RL = 600Ω TO VEE AVCL = 60dB, VOUT = 0 -10 -20 30 100k 1M 20 40 CL = 1nF 10 0 0 -20 -10 -20 10M VCC = 2.5V, VEE = -2.5V RL = 100kΩ TO VEE AVCL = 60dB, VOUT = 0 10k 100k 4000 80 3500 TA = +85°C TA = +85°C 10 40 TA = -25°C TA = +125°C 20 0 0 VCC = 2.5V, VEE = -2.5V RL = 2kΩ TO VEE AVCL = 60dB, VOUT = 0 -10 -20 10k 100k 1M 10M 1.10 3000 2500 2000 1500 STABLE 500 -40 0 1.06 RISING EDGE 1.04 1.02 0.98 0.96 100 FREQUENCY (Hz) 1k 10k 2.0 100k 3.0 4.5 5.0 10 RL = 2kΩ VCC = 5V VIN 100mV/div 5.5 VCC = 2.7V, AV = +10, VOUT = 1Vp-p THD + NOISE (%) 1 VOUT 100mV/div 4.0 TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY LMX321 toc25 LMX321 toc24 3.5 SUPPLY VOLTAGE NONINVERTING SMALL-SIGNAL RESPONSE RL = 2kΩ VCC = 5V VOUT 1V/div 2.5 LOAD RESISTANCE (Ω) NONINVERTING LARGE-SIGNAL RESPONSE VIN 1V/div FALLING EDGE 1.00 1000 -20 RL = 10kΩ VIN = 1V STEP, AVCL = +1V/V 1.08 SLEW RATE (V/µS) 60 PHASE (degrees) GAIN (dB) 20 SLEW RATE vs. SUPPLY VOLTAGE UNSTABLE TA = -40°C TA = +25°C -40 10M 1M LMX321 toc22 100 LOAD CAPACITANCE (pF) TA = +25°C 30 -20 CL = 0 CAPACITIVE-LOAD STABILITY TA = -40°C 40 0 FREQUENCY (Hz) GAIN AND PHASE vs. FREQUENCY AND TEMPERATURE 50 20 CL = 100pF FREQUENCY (Hz) LMX321 toc21 60 CL = 500pF -40 10k CL = 1nF 80 LMX321 toc23 20 CL = 500pF LMX321 toc26 GAIN (dB) 30 100 CL = 0 CL = 100pF 40 GAIN (dB) CL = 0 PHASE (degrees) 40 LMX321 toc20 50 PHASE (degrees) LMX321 toc19 VCC = 5V, AV = +10, VOUT = 2.5Vp-p 0.1 0.01 VCC = 2.7V, AV = +1, VOUT = 1Vp-p VCC = 5V, AV = +1, VOUT = 2.5Vp-p 1µs/div 1µs/div 0.001 10 100 1k 10k 100k FREQUENCY (Hz) _______________________________________________________________________________________ 7 LMX321/LMX358/LMX324 Typical Operating Characteristics (continued) (TA = +25°C, VEE = 0, unless otherwise noted.) Typical Operating Characteristics (continued) (TA = +25°C, VEE = 0, unless otherwise noted.) VCC = 5V 30 25 VCC = 2.7V 20 15 10 30 25 20 VCC = 2.7V 15 10 5 1000 LMX321 toc29 VCC = 5V 35 OUTPUT IMPEDANCE vs. FREQUENCY LMX321 toc28 35 40 SHORT-CIRCUIT CURRENT (mA) LMX321 toc27 40 SHORT-CIRCUIT CURRENT vs. TEMPERATURE (SOURCING) OUTPUT IMPEDANCE (Ω) SHORT-CIRCUIT CURRENT vs. TEMPERATURE (SINKING) SHORT-CIRCUIT CURRENT (mA) LMX321/LMX358/LMX324 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps VCC = 2.7V TO 5V AVCL = +1V/V 100 10 1 0.01 5 0 0 0.001 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (°C) TEMPERATURE (°C) 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz) Pin Description PIN NAME 8 FUNCTION LMX321 LMX358 LMX324 1 — — IN+ Noninverting Amplifier Input 2 4 11 VEE Negative Supply. Connect to ground for single-supply operation. 3 — — IN- Inverting Amplifier Input 4 — — OUT Output 5 8 4 VCC Positive Supply — 1 1 OUT1 — 2 2 IN1- Inverting Input for Amplifier 1 — 3 3 IN1+ Noninverting Input for Amplifier 1 — 7 7 OUT2 Output for Amplifier 2 — 6 6 IN2- Inverting Input for Amplifier 2 — 5 5 IN2+ Noninverting Input for Amplifier 2 — — 8 OUT3 Output for Amplifier 3 — — 9 IN3- Inverting Input for Amplifier 3 — — 10 IN3+ Noninverting Input for Amplifier 3 — — 14 OUT4 Output for Amplifier 4 — — 13 IN4- Inverting Input for Amplifier 4 — — 12 IN4+ Noninverting Input for Amplifier 4 Output for Amplifier 1 _______________________________________________________________________________________ Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324 3.5kΩ RL CL LMX321 LMX358 LMX324 3.5kΩ Figure 3. Capacitive-Load-Driving Circuit Figure 1. Input Protection Circuit VCC = 5V, VEE = 0, CL = 2.2nF RL = 2kΩ VIN 2V/div VIN 100mV/div 2.5V VOUT 1V/div 2.6V 2.4V 2.6V VOUT 100mV/div 2.4V -2.5V 200µs/div 4µs/div VCC = 2.5V, VEE = -2.5V, AVCL = 2V/V Figure 2. Rail-to-Rail Output Swing Detailed Description Input Protection Circuit The LMX321/LMX358/LMX324’s inputs are protected from large differential input voltages by internal 3.5kΩ series resistors and back-to-back triple diode stacks across the inputs (Figure 1). For differential input voltages (much less than 1.8V), input resistance is typically 3MΩ. For differential input voltages greater than 1.8V, input resistance is around 7kΩ, and the input bias current can be approximated by the following equation: IBIAS = (VDIFF - 1.8V) / 7kΩ In the region where the differential input voltage approaches 1.8V, input resistance decreases exponentially from 3MΩ to 7kΩ as the diode block begins conducting. Inversely, the bias current increases with the same curve. Rail-to-Rail Output Stage The LMX321/LMX358/LMX324 drive 2kΩ loads and still typically swing within 40mV of the supply rails. Figure 2 Figure 4. Output With Excessive Capacitive Load shows the output voltage swing of the LMX321 configured with AVCL = +2V/V. Driving Capacitive Loads Driving a capacitive load can cause instability in many op amps, especially those with low quiescent current. The LMX321/LMX358/LMX324 are unity-gain stable for a range of capacitive loads to above 400pF. Figure 4 shows the response of the LMX321 with an excessive capacitive load. Adding a series resistor between the output and the load capacitor (Figure 5) improves the circuit’s response by isolating the load capacitance from the op amp’s output. Applications Information Power-Up The LMX321/LMX358/LMX324 outputs typically settle within 10µs after power-up. Figure 6 shows the output voltage on power-up and power-down. _______________________________________________________________________________________ 9 LMX321/LMX358/LMX324 Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps Power Supplies and Layout The LMX321/LMX358/LMX324 operate from a single +2.3V to +7V power supply. Bypass the power supply with a 0.1µF capacitor to ground as close to VCC as possible. RISO Good layout techniques optimize performance by minimizing the amount of stray capacitance at the op amp’s inputs and outputs. Place external components close to the op amp to minimize trace lengths and stray capacitance. Chip Information LMX321 TRANSISTOR COUNT: 88 LMX358 TRANSISTOR COUNT: 175 CL LMX321 LMX358 LMX324 Figure 5. Capacitive-Load-Driving Circuit With Isolation Resistor LMX324 TRANSISTOR COUNT: 349 PROCESS: Bipolar VCC 2V/div VOUT 1V/div 4µs/div Figure 6. Power-Up/Power-Down Waveform Selector Guide PART 10 AMPLIFIERS PER PACKAGE TOP MARK LMX321AXK-T 1 ACP LMX321AUK-T 1 ADSQ LMX358AKA-T 2 AAIR LMX358ASA 2 — LMX358AUA 2 — LMX324ASD 4 — LMX324AUD 4 — ______________________________________________________________________________________ Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps SC70, 5L.EPS SOT5L.EPS ______________________________________________________________________________________ 11 LMX321/LMX358/LMX324 Package Information Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps 8LUMAXD.EPS SOT23, 8L.EPS LMX321/LMX358/LMX324 Package Information (continued) 12 ______________________________________________________________________________________ Single/Dual/Quad, General Purpose, Low-Voltage, Rail-to-Rail Output Op Amps TSSOP,NO PADS.EPS 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. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 13 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products. LMX321/LMX358/LMX324 Package Information (continued)