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19-2103; Rev 0; 8/01
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps
General Description
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(R) outputs and an input common-mode range that extends below ground. These op amps draw only 105A of quiescent current per amplifier, operate from a single +2.3V to +7V supply, and drive 2k 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
o Upgrade to LMV321/LMV358/LMV324 Family o Single +2.3V to +7V Supply Voltage Range o Available in Space-Saving Packages 5-Pin SC70 (LMX321) 8-Pin SOT23 (LMX358) 14-Pin TSSOP (LMX324) o 1.3MHz Gain-Bandwidth Product o 105A Quiescent Current per Amplifier (VCC = +2.7V) o No Phase Reversal for Overdriven Inputs o No Crossover Distortion o Rail-to-Rail Output Swing o Input Common-Mode Voltage Range: VEE - 0.2V to VCC - 0.8V o Drives 2k Resistive Loads
LMX321/LMX358/LMX324
Applications
Cellular Phones Laptops Low-Power, Low-Voltage Applications Portable/Battery-Powered Equipment Cordless Phones Active Filters
PART LMX321AXK-T LMX321AUK-T LMX358AKA-T LMX358ASA LMX358AUA LMX324ASD LMX324AUD
Ordering Information
TEMP. RANGE -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C -40C to +125C PIN-PACKAGE 5 SC70-5 5 SOT23-5 8 SOT23-8 8 SO 8 MAX 14 SO 14 TSSOP
Selector Guide appears at end of data sheet.
Pin Configurations
TOP VIEW
OUT1 1 IN1- 2 OUT1 1 IN+ 1 VEE 2 IN1+ 3 IN- 3 4 OUT VEE 4 5 IN2+ 6 IN28 VCC 7 OUT2 IN1+ 3 VCC 4 IN2+ 5 IN2- 6 OUT2 7 14 OUT4 13 IN412 IN4+ 11 VEE 10 IN3+ 9 IN38 OUT3
LMX321
5 VCC IN1- 2
LMX358
LMX324
SC70-5/SOT23-5 SOT23-8/SO/MAX
TSSOP/SO
Rail-to-Rail is a registered trademark of Nippon Motorola, Ltd. ________________________________________________________________ Maxim Integrated Products 1
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.
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
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 = +70C) 5-Pin SC70-5 (derate 3.1mW/C above +70C)...........247mW 5-Pin SOT23-5 (derate 7.1mW/C above +70C) ........571mW 8-Pin SOT23-8 (derate 7.52mW/C above +70C) ......602mW 8-Pin SO (derate 5.9mW/C above +70C)..................471mW 8-Pin MAX (derate 4.5mW/C above +70C) .............362mW 14-Pin TSSOP (derate 9.1mW/C above +70C) .........727mW 14-Pin SO (derate 8.3mW/C above +70C)................667mW Operating Temperature Range .........................-40C to +125C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 > 1M, TA = +25C, unless otherwise noted.)
PARAMETER DC Characteristics Input Offset Voltage Input Offset Voltage Average Drift Input Bias Current Input Offset Current Common-Mode Rejection Ratio Power-Supply Rejection Ratio Input Common-Mode Voltage Range Large-Signal Voltage Gain VOS TCVOS IB IOS CMRR PSRR VCM AVOL -0.2V < VCM < 1.8V 2.3V < VCC < 7V, VOUT = 1V For CMRR > 72dB Limit Typ VCC - VOH VOL VCC - VOH VOL 72 82 -0.2 -0.2 20 120 12 10 40 25 105 210 420 1 1.3 64 24 f = 1kHz f = 1kHz 66 0.13 50 40 110 60 150 300 600 V/s MHz degrees dB nV/Hz pA/Hz A mV 1 6 18 1 92 96 1.8 1.9 50 8 6 mV V/oC nA nA dB dB V V/mV SYMBOL CONDITIONS MIN TYP MAX UNITS
RL = 2k to VEE, 0.3V < VOUT < 2.4V RL = 10k to 1.35V
Output Voltage Swing
VOUT RL = 2k to 1.35V LMX321 (Single)
Supply Current AC Characteristics Slew Rate Gain-Bandwidth Product Phase Margin Gain Margin Input Noise Voltage Density Input Current Noise Density
ICC
LMX358 (Dual) LMX324 (Quad)
SR GBW M GM en in
1V step Input CL = 200pF
2
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Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps
ELECTRICAL CHARACTERISTICS
(VCC = +2.7V, VEE = 0, VOUT = VCC/2, VCM = 1V, RL > 1M, TA = -40C to +125C, unless otherwise noted.) (Note 1)
PARAMETER DC Characteristics Input Offset Voltage Input Bias Current Input Offset Current Common-Mode Rejection Ratio Power-Supply Rejection Ratio Input Common-Mode Voltage Range Large-Signal Voltage Gain VOS IB IOS CMRR PSRR VCM AVOL -0.1 < VCM < 1.7V 2.3V < VCC < 7V, VOUT = 1V For CMRR > 60dB Limit Typ VCC - VOH VOL VCC - VOH VOL 60 75 -0.1 -0.1 10 130 50 150 70 180 360 720 A mV 1.7 1.8 9 70 15 mV nA nA dB dB V V/mV SYMBOL CONDITIONS MIN TYP MAX UNITS
LMX321/LMX358/LMX324
RL = 2k to VEE, 0.3V < VOUT < 2.4V RL = 10k to 1.55V
Output Voltage Swing
VOUT RL = 2k to 1.35V LMX321 (Single)
Supply Current
ICC
LMX358 (Dual) LMX324 (Quad)
ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1M, TA = +25C, unless otherwise noted.)
PARAMETER DC Characteristics Input Offset Voltage Input Offset Voltage Average Drift Input Bias Current Input Offset Current Common-Mode Rejection Ratio Power-Supply Rejection Ratio Input Common-Mode Voltage Range Large-Signal Voltage Gain VOS TCVOS IB IOS CMRR PSRR VCM AVOL -0.2 < VCM < 4.1V 2.3V < VCC < 7V, VOUT = 1V, VCM = 1V For CMRR > 72dB RL = 2k to VEE, 0.3V < VOUT < 4.7V Limit Typ 72 82 -0.2 -0.2 40 200 1 6 18 1 92 96 4.1 4.2 50 8 6 mV V/oC nA nA dB dB V V/mV SYMBOL CONDITIONS MIN TYP MAX UNITS
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3
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1M, TA = +25C, unless otherwise noted.)
PARAMETER SYMBOL CONDITIONS RL = 10k to 2.5V Output Voltage Swing VOUT RL = 2k to 2.5V Output Short-Circuit Current ISC Sourcing, VOUT = 0 Sinking, VOUT = 5V LMX321 (Single) Supply Current AC Characteristics Slew Rate Gain-Bandwidth Product Phase Margin Gain Margin Input Noise Voltage Density Input Noise Current Density SR GBW M GM en in f = 1kHz f = 1kHz 3V step input CL = 200pF 1 1.3 65 25 65 0.13 V/s MHz degrees dB nV/Hz pA/Hz ICC LMX358 (Dual) LMX324 (Quad) VCC - VOH VOL VCC - VOH VOL 5 10 MIN TYP 20 12 65 40 25 28 120 240 480 170 340 680 A MAX 60 40 130 80 mA mV UNITS
ELECTRICAL CHARACTERISTICS
(VCC = +5V, VEE = 0, VOUT = VCC/2, VCM = 2V, RL > 1M, TA = -40C to +125C, unless otherwise noted.) (Note 1)
PARAMETER DC Characteristics Input Offset Voltage Input Bias Current Input Offset Current Common-Mode Rejection Ratio Power-Supply Rejection Ratio Input Common-Mode Voltage Range Large-Signal Voltage Gain VOS IB IOS CMRR PSRR VCM AVOL -0.1 < VCM < 4.0V 2.3V < VCC < 7V, VOUT = 1V, VCM = 1V For CMRR > 63dB Limit Typ VCC - VOH VOL VCC - VOH VOL 63 75 -0.1 -0.1 20 170 70 190 90 210 420 840 A mV 4.0 4.1 9 70 15 mV nA nA dB dB V V/mV SYMBOL CONDITIONS MIN TYP MAX UNITS
RL = 2k to VEE, 0.3V < VOUT < 4.7V RL = 10k to 2.5V
Output Voltage Swing
VOUT RL = 2k to 2.5V LMX321 (Single)
Supply Current
ICC
LMX358 (Dual) LMX324 (Quad)
Note 1: Specifications are 100% tested at TA = +25C (exceptions noted). All temperature limits are guaranteed by design.
4
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Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps
Typical Operating Characteristics
(TA = +25C, VEE = 0, unless otherwise noted.)
LMX321/LMX358/LMX324
SUPPLY CURRENT PER AMPLIFIER vs. SUPPLY VOLTAGE
LMX321 toc01
INPUT BIAS CURRENT vs. TEMPERATURE
LMX321 toc02
SOURCE CURRENT vs. OUTPUT VOLTAGE
VCC = 2.7V
LMX321 toc03
160 SUPPLY CURRENT PER AMPLIFIER (A) 140 120 100 80 60 40 20 0 0 1 2 3 4 5 6 TA = +25C TA = -40C TA = +85C TA = +125C
-10 -11 INPUT BIAS CURRENT (nA) -12 -13 -14 -15 -16 -17 -18 -19 -20 VCC = +5V, VIN = VCC/2
100
SOURCE CURRENT (mA)
10
1
0.1
0.01 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) 0.01 0.1 1 10 OUTPUT VOLTAGE REFERENCED TO VCC (V)
7
SUPPLY VOLTAGE (V)
SOURCE CURRENT vs. OUTPUT VOLTAGE
LMX321 toc04
SINK CURRENT vs. OUTPUT VOLTAGE
LMX321 toc05
SINK CURRENT vs. OUTPUT VOLTAGE
VCC = 5V
LMX321 toc06
100 VCC = 5V 10
100
VCC = 2.7V
100
SOURCE CURRENT (mA)
SINK CURRENT (mA)
1
1
SINK CURRENT (mA) 0.01 0.1 1 10
10
10
1
0.1
0.1
0.1
0.01 0.01 0.1 1 10 OUTPUT VOLTAGE REFERENCED TO VCC (V)
0.01 0.001
0.01 0.001
0.01
0.1
1
10
OUTPUT VOLTAGE REFERENCED TO VEE (V)
OUTPUT VOLTAGE REFERENCED TO VEE (V)
OUTPUT VOLTAGE SWING vs. SUPPLY VOLTAGE
LMX321 toc07
OUTPUT VOLTAGE SWING vs. SUPPLY VOLTAGE
LMX321 toc08
INPUT VOLTAGE NOISE vs. FREQUENCY
600 550 500 450 400 350 300 250 200 150 100 50 0 1 10 VCC = 2.7V TO 5V, VCM = VCC/2
LMX321 toc09
100 RL = 2k 90 OUTPUT VOLTAGE SWING (mV) 80 70 60 50 40 30 20 2 3 4 5 6 7 SUPPLY VOLTAGE (V) NEGATIVE SWING (VOL) POSITIVE SWING (VCC - VOH)
35 RL = 10k OUTPUT VOLTAGE SWING (mV) 30 25 20 15 10 NEGATIVE SWING (VOL) 5 2 3 4 5 6 7 SUPPLY VOLTAGE (V) POSITIVE SWING (VCC - VOH)
INPUT VOLTAGE NOISE (nV/Hz)
100
1k
10k
100k
FREQUENCY (Hz)
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5
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
Typical Operating Characteristics (continued)
(TA = +25C, VEE = 0, unless otherwise noted.)
INPUT CURRENT NOISE vs. FREQUENCY
LMX321 toc10
CROSSTALK REJECTION vs. FREQUENCY
LMX321 toc11
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
VCC = 2.7V TO 5V -20 -40 PSRRLMX321 toc12
4.0 INPUT CURRENT NOISE (pA/Hz) 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 1 10
VCC = 2.7V TO 5V, VCM = VCC/2
-50 CROSSTALK REJECTION (dB) -70 -90 -110 -130 -150
VCC = 5V, RL = 5k
0
PSRR (dB)
-60 -80 -100 -120
PSRR+
100
1k
10k
100k
100
1k
10k
100k
1M
10M
100M
100
1k
10k FREQUENCY (Hz)
100k
1M
FREQUENCY (Hz)
FREQUENCY (Hz)
INPUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE
LMX321 toc13
INPUT OFFSET VOLTAGE vs. COMMON-MODE VOLTAGE
LMX321 toc14
INPUT OFFSET VOLTAGE vs. OUTPUT VOLTAGE
VCC = 2.5V, VEE = -2.5V RL = 600 RL = 2k 75 INPUT OFFSET VOLTAGE (V) 50 25 0 -25 -50 -75 -100 RL = 10k
LMX321 toc15
0.10 VCC = 1.35V, VEE = -1.35V 0.05 0 VOS (mV) -0.05 -0.10 -0.15 -0.20 -1.7 -1.2 -0.7 -0.2 0.3
0.15 0.10 0.05 VOS (mV) 0 -0.05 -0.10 -0.15 -0.20
VCC = 2.5V, VEE = -2.5V
100
0.8
-2.8 -2.3 -1.8 -1.3 -0.8 -0.3 0.2 0.7 1.2 1.7 2.2 COMMON-MODE VOLTAGE (V)
-3
-2
-1
0
1
2
3
COMMON-MODE VOLTAGE (V)
OUTPUT VOLTAGE (V)
INPUT OFFSET VOLTAGE vs. OUTPUT VOLTAGE
VCC = 1.35V, VEE = -1.35V RL = 600
LMX321 toc16
GAIN AND PHASE vs. FREQUENCY and RESISTIVE LOAD
50 40 30
GAIN (dB)
LMX321 toc17
GAIN AND PHASE vs. FREQUENCY AND RESISTIVE LOAD
100 80
50 40 PHASE MARGIN (degrees) 30 GAIN (dB) 20 10 0 -10 -20 VCC = 1.35V, VEE = -1.35V CL = 0, RL TO VEE AVCL = 60dB, VOUT = 0 RL = 100k 10k 100k 1M 10M RL = 600 RL = 100k
LMX321 toc18
100 75 INPUT OFFSET VOLTAGE (mV) 50 25 0 -25 -50 -75 100 -1.5 -1.0 -0.5 RL = 10k
100 80 60 40 20 0 -20 -40
RL = 600
RL = 100k
RL = 2k
20 10 0 RL = 600k
40 20 0 VCC = 2.5V, VEE = -2.5V CL = 0, RL TO VEE AVCL = 60dB, VOUT = 0 RL = 100k 10k 100k 1M 10M -20 -40 FREQUENCY (Hz)
-10 -20
0 0.5 1.0 1.5 OUTPUT VOLTAGE (V)
FREQUENCY (Hz)
6
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PHASE (degrees)
60
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
Typical Operating Characteristics (continued)
(TA = +25C, VEE = 0, unless otherwise noted.)
GAIN AND PHASE vs. FREQUENCY AND CAPACTIVE LOAD
50 40 30 GAIN (dB) 20 10 0 -10 -20 10k 100k 1M 10M FREQUENCY (Hz) VCC = 2.5V, VEE = -2.5V RL = 600 TO VEE AVCL = 60dB, VOUT = 0 CL = 0 CL = 500pF CL = 1nF 20 0 -20 -40
LMX321 toc19
GAIN AND PHASE vs. FREQUENCY AND CAPACITIVE LOAD
100 80 60 40 50 40 PHASE (degrees) 30 GAIN (dB) 20 10 0 -10 -20 CL = 1nF CL = 500pF CL = 100pF VCC = 2.5V, VEE = -2.5V RL = 100k TO VEE AVCL = 60dB, VOUT = 0 10k 100k 0 -20 CL = 0 1M -40 10M
LMX321 toc20
100 80 60 40 20
CL = 0 CL = 100pF CL = 500pF CL = 1nF
FREQUENCY (Hz)
GAIN AND PHASE vs. FREQUENCY AND TEMPERATURE
50 40 TA = -40C 30 GAIN (dB) 20 10 0 -10 -20 VCC = 2.5V, VEE = -2.5V RL = 2k TO VEE AVCL = 60dB, VOUT = 0 10k 100k 1M 10M FREQUENCY (Hz) PHASE (degrees) TA = +25C TA = +85C TA = +125C TA = +85C TA = -25C 60 40 20 0 -20 -40
LMX321 toc21
CAPACITIVE-LOAD STABILITY
LMX321 toc22
SLEW RATE vs. SUPPLY VOLTAGE
RL = 10k VIN = 1V STEP, AVCL = +1V/V
LMX321 toc23
100 80 LOAD CAPACITANCE (pF)
TA = -40C TA = +25C
4000 3500 UNSTABLE 3000
1.10 1.08 SLEW RATE (V/S) 1.06 RISING EDGE 1.04 1.02 1.00
2500 2000 1500 1000 STABLE 500 0 100 1k 10k 100k LOAD RESISTANCE ()
FALLING EDGE
0.98 0.96 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE
NONINVERTING LARGE-SIGNAL RESPONSE
LMX321 toc24
NONINVERTING SMALL-SIGNAL RESPONSE
LMX321 toc25
TOTAL HARMONIC DISTORTION PLUS NOISE vs. FREQUENCY
LMX321 toc26
RL = 2k VCC = 5V VIN 1V/div VIN 100mV/div
RL = 2k VCC = 5V
10
1
THD + NOISE (%)
VCC = 2.7V, AV = +10, VOUT = 1Vp-p VCC = 5V, AV = +10, VOUT = 2.5Vp-p
0.1
VOUT 1V/div
VOUT 100mV/div
0.01
VCC = 2.7V, AV = +1, VOUT = 1Vp-p VCC = 5V, AV = +1, VOUT = 2.5Vp-p
1s/div
1s/div
0.001 10 100 1k FREQUENCY (Hz) 10k 100k
_______________________________________________________________________________________
PHASE (degrees)
7
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
Typical Operating Characteristics (continued)
(TA = +25C, VEE = 0, unless otherwise noted.)
SHORT-CIRCUIT CURRENT vs. TEMPERATURE (SINKING)
LMX321 toc27
SHORT-CIRCUIT CURRENT vs. TEMPERATURE (SOURCING)
LMX321 toc28
OUTPUT IMPEDANCE vs. FREQUENCY
VCC = 2.7V TO 5V AVCL = +1V/V
LMX321 toc29
40 SHORT-CIRCUIT CURRENT (mA) 35 30 25 20 15 10 5 0 VCC = 5V
40 SHORT-CIRCUIT CURRENT (mA) 35 30 25 20 15 10 5 0 VCC = 2.7V VCC = 5V
1000
OUTPUT IMPEDANCE ()
100
VCC = 2.7V
10
1
0.01
0.001 -40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C) 100 1k 10k 100k 1M 10M 100M FREQUENCY (Hz)
-40 -25 -10 5 20 35 50 65 80 95 110 125 TEMPERATURE (C)
Pin Description
PIN NAME LMX321 1 2 3 4 5 -- -- -- -- -- -- -- -- -- -- -- -- LMX358 -- 4 -- -- 8 1 2 3 7 6 5 -- -- -- -- -- -- LMX324 -- 11 -- -- 4 1 2 3 7 6 5 8 9 10 14 13 12 IN+ VEE INOUT VCC OUT1 IN1IN1+ OUT2 IN2IN2+ OUT3 IN3IN3+ OUT4 IN4IN4+ Noninverting Amplifier Input Negative Supply. Connect to ground for single-supply operation. Inverting Amplifier Input Output Positive Supply Output for Amplifier 1 Inverting Input for Amplifier 1 Noninverting Input for Amplifier 1 Output for Amplifier 2 Inverting Input for Amplifier 2 Noninverting Input for Amplifier 2 Output for Amplifier 3 Inverting Input for Amplifier 3 Noninverting Input for Amplifier 3 Output for Amplifier 4 Inverting Input for Amplifier 4 Noninverting Input for Amplifier 4 FUNCTION
8
_______________________________________________________________________________________
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
3.5k
RL
CL
3.5k
LMX321 LMX358 LMX324
Figure 1. Input Protection Circuit
VIN 2V/div 2.5V
Figure 3. Capacitive-Load-Driving Circuit
VCC = 5V, VEE = 0, CL = 2.2nF RL = 2k VIN 100mV/div
2.6V
2.4V
VOUT 1V/div
VOUT 100mV/div
2.6V
2.4V
-2.5V 200s/div VCC = 2.5V, VEE = -2.5V, AVCL = 2V/V
4s/div
Figure 2. Rail-to-Rail Output Swing
Figure 4. Output With Excessive Capacitive Load
Detailed Description
Input Protection Circuit
The LMX321/LMX358/LMX324's inputs are protected from large differential input voltages by internal 3.5k 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 3M. For differential input voltages greater than 1.8V, input resistance is around 7k, and the input bias current can be approximated by the following equation: IBIAS = (VDIFF - 1.8V) / 7k In the region where the differential input voltage approaches 1.8V, input resistance decreases exponentially from 3M to 7k as the diode block begins conducting. Inversely, the bias current increases with the same curve.
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 10s after power-up. Figure 6 shows the output voltage on power-up and power-down.
Rail-to-Rail Output Stage
The LMX321/LMX358/LMX324 drive 2k loads and still typically swing within 40mV of the supply rails. Figure 2
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9
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
Power Supplies and Layout
The LMX321/LMX358/LMX324 operate from a single +2.3V to +7V power supply. Bypass the power supply with a 0.1F capacitor to ground as close to VCC as possible. 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.
RISO CL LMX321 LMX358 LMX324
Chip Information
LMX321 TRANSISTOR COUNT: 88 LMX358 TRANSISTOR COUNT: 175 LMX324 TRANSISTOR COUNT: 349 PROCESS: Bipolar
Figure 5. Capacitive-Load-Driving Circuit With Isolation Resistor
VCC 2V/div
VOUT 1V/div
4s/div
Figure 6. Power-Up/Power-Down Waveform
Selector Guide
PART LMX321AXK-T LMX321AUK-T LMX358AKA-T LMX358ASA LMX358AUA LMX324ASD LMX324AUD AMPLIFIERS PER PACKAGE 1 1 2 2 2 4 4 TOP MARK ACP ADSQ AAIR -- -- -- --
10
______________________________________________________________________________________
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps
Package Information
SC70, 5L.EPS
LMX321/LMX358/LMX324
______________________________________________________________________________________
SOT5L.EPS
11
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps LMX321/LMX358/LMX324
Package Information (continued)
SOT23, 8L.EPS
12
______________________________________________________________________________________
8LUMAXD.EPS
Single/Dual/Quad, General Purpose, Low-Voltage, Rail-to-Rail Output Op Amps
Package Information (continued)
TSSOP,NO PADS.EPS
LMX321/LMX358/LMX324
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 (c) 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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