Maxim LMX324 Single/dual/quad, general-purpose, low-voltage, rail-to-rail output op amp Datasheet

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)
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