LMX324ASD [MAXIM]
Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps; 单/双/四路,通用,低电压,轨至轨输出运算放大器型号: | LMX324ASD |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Single/Dual/Quad, General-Purpose, Low-Voltage, Rail-to-Rail Output Op Amps |
文件: | 总13页 (文件大小:491K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
19-2103; Rev 0; 8/01
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
General Description
Features
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 pur-
ꢀ Upgrade to LMV321/LMV358/LMV324 Family
ꢀ Single +2.3V to +7V Supply Voltage Range
®
ꢀ Available in Space-Saving Packages
5-Pin SC70 (LMX321)
pose op amps. These devices offer Rail-to-Rail out-
puts and an input common-mode range that extends
below ground. These op amps draw only 105µA of qui-
escent 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.
8-Pin SOT23 (LMX358)
14-Pin TSSOP (LMX324)
ꢀ 1.3MHz Gain-Bandwidth Product
ꢀ 105µA Quiescent Current per Amplifier
(V
= +2.7V)
CC
ꢀ No Phase Reversal for Overdriven Inputs
ꢀ No Crossover Distortion
ꢀ Rail-to-Rail Output Swing
The LMX321 single op amp is available in ultra-small 5-
pin 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 avail-
able in 14-pin TSSOP and SO packages.
ꢀ Input Common-Mode Voltage Range: V - 0.2V
EE
to V
- 0.8V
CC
ꢀ Drives 2kΩ Resistive Loads
Ordering Information
Applications
Cellular Phones
PART
TEMP. RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
5 SC70-5
5 SOT23-5
8 SOT23-8
8 SO
LMX321AXK-T
LMX321AUK-T
LMX358AKA-T
LMX358ASA
LMX358AUA
LMX324ASD
LMX324AUD
Laptops
Low-Power, Low-Voltage Applications
Portable/Battery-Powered Equipment
Cordless Phones
8 µMAX
Active Filters
14 SO
14 TSSOP
Selector Guide appears at end of data sheet.
Pin Configurations
TOP VIEW
OUT1
IN1-
1
2
3
4
5
6
7
OUT4
IN4-
14
13
12
OUT1
IN1-
V
CC
1
2
3
4
8
7
IN1+
IN4+
LMX358
IN+
V
CC
1
2
3
5
4
LMX321
OUT2
IN2-
V
CC
11 V
EE
LMX324
V
EE
IN1+
6
5
IN2+
IN2-
10 IN3+
OUT
IN-
IN2+
V
EE
9
8
IN3-
SC70-5/SOT23-5
SOT23-8/SO/µMAX
OUT3
OUT2
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
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
Differential Input Voltage (V
to V ) ....................................-0.3V to +8V
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
CC
EE
- V )........................V to V
IN+
IN- EE CC
OUT_ to V ...............................................-0.3V to (V
+ 0.3V)
EE
CC
Output Short-Circuit Duration
OUT_ Shorted to V
Continuous Power Dissipation (T = +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
or V ..................................Continuous
CC
EE
A
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
(V
= +2.7V, V = 0, V
= V /2, V
= 1V, R > 1MΩ, T = +25°C, unless otherwise noted.)
CC
EE
OUT
CC
CM
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC Characteristics
Input Offset Voltage
V
1
6
6
mV
OS
Input Offset Voltage Average
Drift
TCV
µV/oC
OS
Input Bias Current
Input Offset Current
I
18
1
50
8
nA
nA
B
I
OS
Common-Mode Rejection
Ratio
CMRR
PSRR
-0.2V < V
< 1.8V
72
92
96
dB
dB
CM
Power-Supply Rejection Ratio
2.3V < V
< 7V, V
= 1V
OUT
82
-0.2
-0.2
20
CC
Limit
1.8
1.9
Input Common-Mode Voltage
Range
V
For CMRR > 72dB
R = 2kΩ to V , 0.3V < V
V
CM
Typ
OUT
Large-Signal Voltage Gain
A
< 2.4V
120
12
V/mV
VOL
L
EE
V
V
V
V
- V
50
40
CC
OL
CC
OL
OH
R = 10kΩ to 1.35V
L
10
Output Voltage Swing
V
mV
µA
OUT
- V
40
110
60
OH
R = 2kΩ to 1.35V
L
25
LMX321 (Single)
LMX358 (Dual)
LMX324 (Quad)
105
210
420
150
300
600
Supply Current
I
CC
AC Characteristics
Slew Rate
SR
1V step Input
1
1.3
64
V/µs
MHz
Gain-Bandwidth Product
Phase Margin
GBW
C = 200pF
L
degrees
φ
M
Gain Margin
GM
24
dB
Input Noise Voltage Density
Input Current Noise Density
e
f = 1kHz
f = 1kHz
66
nV/√Hz
pA/√Hz
n
i
n
0.13
2
_______________________________________________________________________________________
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
ELECTRICAL CHARACTERISTICS
(V
= +2.7V, V = 0, V
= V /2, V
= 1V, R > 1MΩ, T = -40°C to +125°C, unless otherwise noted.) (Note 1)
CC
EE
OUT
CC
CM
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC Characteristics
Input Offset Voltage
Input Bias Current
Input Offset Current
V
9
mV
nA
nA
OS
I
70
15
B
I
OS
Common-Mode Rejection
Ratio
CMRR
PSRR
-0.1 < V
< 1.7V
60
dB
dB
CM
Power-Supply Rejection Ratio
2.3V < V < 7V, V
CC
= 1V
75
-0.1
-0.1
10
OUT
Limit
Typ
< 2.4V
1.7
1.8
Input Common-Mode Voltage
Range
V
For CMRR > 60dB
V
CM
Large-Signal Voltage Gain
A
R = 2kΩ to V , 0.3V < V
L
V/mV
VOL
EE
OUT
V
V
V
V
- V
130
50
CC
OL
CC
OL
OH
R = 10kΩ to 1.55V
L
Output Voltage Swing
V
mV
µA
OUT
- V
150
70
OH
R = 2kΩ to 1.35V
L
LMX321 (Single)
LMX358 (Dual)
LMX324 (Quad)
180
360
720
Supply Current
I
CC
ELECTRICAL CHARACTERISTICS
(V
= +5V, V = 0, V
= V /2, V
= 2V, R > 1MΩ, T = +25°C, unless otherwise noted.)
CC
EE
OUT
CC
CM
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC Characteristics
Input Offset Voltage
V
1
6
6
mV
OS
Input Offset Voltage Average
Drift
TCV
µV/oC
OS
Input Bias Current
Input Offset Current
I
18
1
50
8
nA
nA
B
I
OS
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
CMRR
PSRR
-0.2 < V
< 4.1V
72
82
92
96
dB
dB
CM
2.3V < V
< 7V, V
= 1V,
OUT
CC
V
= 1V
CM
Limit
Typ
-0.2
-0.2
4.1
4.2
Input Common-Mode Voltage
Range
V
For CMRR > 72dB
V
CM
R = 2kΩ to V
,
EE
L
Large-Signal Voltage Gain
A
40
200
V/mV
VOL
0.3V < V
< 4.7V
OUT
_______________________________________________________________________________________
3
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
ELECTRICAL CHARACTERISTICS (continued)
(V
= +5V, V = 0, V
= V /2, V
= 2V, R > 1MΩ, T = +25°C, unless otherwise noted.)
CM L A
CC
EE
OUT
CC
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
20
MAX
60
UNITS
V
V
V
V
- V
- V
CC
OL
CC
OL
OH
R = 10kΩ to 2.5V
L
12
40
Output Voltage Swing
V
mV
OUT
65
130
80
OH
R = 2kΩ to 2.5V
L
40
Sourcing, V
= 0
5
25
OUT
Output Short-Circuit Current
Supply Current
I
mA
µA
SC
Sinking, V
= 5V
10
28
OUT
LMX321 (Single)
LMX358 (Dual)
LMX324 (Quad)
120
240
480
170
340
680
I
CC
AC Characteristics
Slew Rate
SR
3V step input
1
1.3
65
V/µs
MHz
Gain-Bandwidth Product
Phase Margin
GBW
C = 200pF
L
φ
M
degrees
dB
Gain Margin
GM
25
Input Noise Voltage Density
Input Noise Current Density
e
f = 1kHz
f = 1kHz
65
nV/√Hz
pA/√Hz
n
i
n
0.13
ELECTRICAL CHARACTERISTICS
(V
= +5V, V = 0, V
= V /2, V
= 2V, R > 1MΩ, T = -40°C to +125°C, unless otherwise noted.) (Note 1)
CC
EE
OUT
CC
CM
L
A
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC Characteristics
Input Offset Voltage
Input Bias Current
Input Offset Current
V
9
mV
nA
nA
OS
I
70
15
B
I
OS
Common-Mode Rejection Ratio
Power-Supply Rejection Ratio
CMRR
PSRR
-0.1 < V
< 4.0V
63
dB
dB
CM
2.3V < V
< 7V, V
= 1V, V = 1V
CM
75
-0.1
-0.1
20
CC
OUT
Limit
Typ
4.0
4.1
Input Common-Mode Voltage
Range
V
For CMRR > 63dB
R = 2kΩ to V , 0.3V < V
V
CM
Large-Signal Voltage Gain
A
< 4.7V
V/mV
VOL
L
EE
OUT
V
V
V
V
- V
170
70
CC
OL
CC
OL
OH
R = 10kΩ to 2.5V
L
Output Voltage Swing
V
mV
µA
OUT
- V
190
90
OH
R = 2kΩ to 2.5V
L
LMX321 (Single)
LMX358 (Dual)
LMX324 (Quad)
210
420
840
Supply Current
I
CC
Note 1: Specifications are 100% tested at T = +25°C (exceptions noted). All temperature limits are guaranteed by design.
A
4
_______________________________________________________________________________________
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Typical Operating Characteristics
(T = +25°C, V = 0, unless otherwise noted.)
A
EE
SUPPLY CURRENT PER AMPLIFIER
vs. SUPPLY VOLTAGE
SOURCE CURRENT
vs. OUTPUT VOLTAGE
INPUT BIAS CURRENT
vs. TEMPERATURE
160
140
120
100
80
-10
-11
-12
-13
-14
-15
-16
-17
-18
100
10
V
= 2.7V
CC
T
= +125°C
A
T
= +85°C
A
1
T
= +25°C
A
60
V
= +5V, V = V /2
IN CC
CC
40
0.1
0.01
T
= -40°C
A
20
-19
-20
0
0
1
2
3
4
5
6
7
-40 -25 -10
5
20 35 50 65 80 95 110 125
0.01
0.1
1
10
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
OUTPUT VOLTAGE REFERENCED TO V (V)
CC
SOURCE CURRENT
vs. OUTPUT VOLTAGE
SINK CURRENT
vs. OUTPUT VOLTAGE
SINK CURRENT
vs. OUTPUT VOLTAGE
100
10
100
10
100
10
V
= 2.7V
CC
V
CC
= 5V
V
= 5V
CC
1
1
1
0.1
0.01
0.1
0.1
0.01
0.01
0.01
0.1
1
10
0.001
0.01
0.1
1
10
0.001
0.01
0.1
1
10
OUTPUT VOLTAGE REFERENCED TO V (V)
CC
OUTPUT VOLTAGE REFERENCED TO V (V)
EE
OUTPUT VOLTAGE REFERENCED TO V (V)
EE
OUTPUT VOLTAGE SWING
vs. SUPPLY VOLTAGE
OUTPUT VOLTAGE SWING
vs. SUPPLY VOLTAGE
INPUT VOLTAGE NOISE
vs. FREQUENCY
600
550
500
450
400
350
300
250
200
150
100
50
100
90
80
70
60
50
40
30
20
35
30
25
20
15
10
5
V
= 2.7V TO 5V, V = V /2
CM CC
CC
R = 2kΩ
R = 10kΩ
L
L
POSITIVE SWING
(V - V
POSITIVE SWING
)
OH
(V - V
CC
)
CC
OH
NEGATIVE SWING (V
)
OL
NEGATIVE SWING (V
)
OL
0
2
3
4
5
6
7
2
3
4
5
6
7
1
10
100
1k
10k
100k
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
FREQUENCY (Hz)
_______________________________________________________________________________________
5
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Typical Operating Characteristics (continued)
(T = +25°C, V = 0, unless otherwise noted.)
A
EE
CROSSTALK REJECTION
vs. FREQUENCY
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
INPUT CURRENT NOISE
vs. FREQUENCY
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0
0
-20
V
= 2.7V TO 5V, V = V /2
V
= 5V, R = 5kΩ
CC L
CC
CM
CC
V
= 2.7V TO 5V
CC
-50
PSRR-
-70
-90
-40
PSRR+
-60
-110
-80
-130
-150
-100
-120
1
10
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
INPUT OFFSET VOLTAGE
vs. OUTPUT VOLTAGE
INPUT OFFSET VOLTAGE
vs. COMMON-MODE VOLTAGE
0.15
0.10
0.05
0
100
75
0.10
0.05
0
V
= 2.5V, V = -2.5V
EE
V
= 2.5V, V = -2.5V
CC
CC
EE
V
= 1.35V, V = -1.35V
EE
CC
R = 600Ω
L
50
25
R = 2kΩ
L
0
-0.05
-0.10
-0.15
-0.20
-0.05
-0.10
-0.15
-0.20
R = 10kΩ
L
-25
-50
-75
-100
-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
-1.7
-1.2
-0.7
-0.2
0.3
0.8
OUTPUT VOLTAGE (V)
COMMON-MODE VOLTAGE (V)
GAIN AND PHASE vs. FREQUENCY
AND RESISTIVE LOAD
GAIN AND PHASE vs. FREQUENCY
INPUT OFFSET VOLTAGE
vs. OUTPUT VOLTAGE
and RESISTIVE LOAD
LMX321 toc18
LMX321 toc17
50
40
30
20
10
0
100
80
60
40
20
0
50
40
30
20
10
0
100
80
60
40
20
0
100
75
V
= 1.35V, V = -1.35V
EE
CC
R = 600Ω
L
R = 600Ω
L
R = 100kΩ
L
50
R = 100kΩ
L
25
R = 2kΩ
L
0
R = 600kΩ
L
R = 600Ω
L
R = 10kΩ
L
-25
-50
-75
100
V
= 1.35V, V = -1.35V
EE
CC
V
= 2.5V, V = -2.5V
EE
CC
-10
-20
-20
-40
-10
-20
-20
-40
C = 0, R TO V
L
L
EE
OUT
C = 0, R TO V
L
L
EE
OUT
A
= 60dB, V
= 0
VCL
R = 100kΩ
R = 100kΩ
A
= 60dB, V
= 0
L
L
VCL
10k
100k
1M
10M
-1.5
-1.0
-0.5
0
0.5
1.0
1.5
10k
100k
1M
10M
FREQUENCY (Hz)
OUTPUT VOLTAGE (V)
FREQUENCY (Hz)
6
_______________________________________________________________________________________
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Typical Operating Characteristics (continued)
(T = +25°C, V = 0, unless otherwise noted.)
A
EE
GAIN AND PHASE vs. FREQUENCY
AND CAPACTIVE LOAD
GAIN AND PHASE vs. FREQUENCY
AND CAPACITIVE LOAD
LMX321 toc19
LMX321 toc20
50
40
30
20
10
0
100
80
60
40
20
0
50
40
30
20
10
0
100
80
60
40
20
0
C = 0
L
C = 100pF
L
C = 500pF
L
C = 0
L
C = 1nF
L
C = 500pF
L
C = 1nF
L
C = 1nF
L
C = 500pF
L
C = 100pF
L
V
= 2.5V, V = -2.5V
EE
CC
V
= 2.5V, V = -2.5V
EE
CC
-10
-20
-20
-40
-10
-20
-20
-40
R = 600Ω TO V
L
EE
OUT
R = 100kΩ TO V
L
EE
OUT
A
= 60dB, V
= 0
VCL
A
= 60dB, V
= 0
C = 0
L
VCL
10k
100k
1M
10M
10k
100k
1M
10M
FREQUENCY (Hz)
FREQUENCY (Hz)
GAIN AND PHASE vs. FREQUENCY
AND TEMPERATURE
SLEW RATE vs.
SUPPLY VOLTAGE
CAPACITIVE-LOAD STABILITY
LMX321 toc21
50
40
30
20
10
0
100
80
60
40
20
0
4000
1.10
T
= -40°C
R = 10kΩ
IN
A
L
V
= 1V STEP, A = +1V/V
3500
3000
2500
2000
1500
1000
500
VCL
1.08
1.06
1.04
1.02
1.00
0.98
0.96
T
= +25°C
A
UNSTABLE
T
= -40°C
A
T
= +25°C
A
RISING EDGE
T
= +85°C
A
T
= +85°C
A
T
= -25°C
A
T
= +125°C
A
FALLING EDGE
STABLE
V
= 2.5V, V = -2.5V
EE
CC
-10
-20
-20
-40
R = 2kΩ TO V
L
EE
A
= 60dB, V
= 0
VCL
OUT
0
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE
10k
100k
1M
10M
100
1k
10k
100k
FREQUENCY (Hz)
LOAD RESISTANCE (Ω)
NONINVERTING
SMALL-SIGNAL RESPONSE
TOTAL HARMONIC DISTORTION
PLUS NOISE vs. FREQUENCY
NONINVERTING
LARGE-SIGNAL RESPONSE
LMX321 toc25
LMX321 toc24
10
1
R = 2kΩ
CC
L
R = 2kΩ
CC
L
V
= 5V
V
= 5V
V
IN
V
= 2.7V, A = +10, V
= 1Vp-p
CC
V
OUT
V
100mV/div
IN
1V/div
V
= 5V, A = +10, V
= 2.5Vp-p
CC
V
OUT
0.1
V
OUT
V
OUT
1V/div
100mV/div
V
= 2.7V, A = +1, V
= 1Vp-p
CC
V
OUT
0.01
0.001
V
= 5V, A = +1, V
= 2.5Vp-p
OUT
CC
V
1µs/div
10
100
1k
FREQUENCY (Hz)
10k
100k
1µs/div
_______________________________________________________________________________________
7
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Typical Operating Characteristics (continued)
(T = +25°C, V = 0, unless otherwise noted.)
A
EE
SHORT-CIRCUIT CURRENT
vs. TEMPERATURE (SINKING)
SHORT-CIRCUIT CURRENT
vs. TEMPERATURE (SOURCING)
OUTPUT IMPEDANCE
vs. FREQUENCY
40
35
30
25
20
40
35
30
25
20
1000
100
10
V
A
= 2.7V TO 5V
VCL
CC
V
= 5V
= +1V/V
CC
V
= 5V
CC
V
= 2.7V
CC
V
= 2.7V
CC
1
15
10
15
10
0.01
0.001
5
0
5
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
100
1k
10k
100k
1M
10M 100M
TEMPERATURE (°C)
TEMPERATURE (°C)
FREQUENCY (Hz)
Pin Description
PIN
LMX358
—
NAME
FUNCTION
LMX321
LMX324
1
—
IN+
Noninverting Amplifier Input
Negative Supply. Connect to ground for single-supply
operation.
2
4
11
V
EE
3
—
—
8
—
—
4
IN-
Inverting Amplifier Input
Output
4
OUT
5
V
Positive Supply
CC
—
—
—
—
—
—
—
—
—
—
—
—
1
1
OUT1
IN1-
Output for Amplifier 1
2
2
Inverting Input for Amplifier 1
Noninverting Input for Amplifier 1
Output for Amplifier 2
3
3
IN1+
OUT2
IN2-
7
7
6
6
Inverting Input for Amplifier 2
Noninverting Input for Amplifier 2
Output for Amplifier 3
5
5
IN2+
OUT3
IN3-
—
—
—
—
—
—
8
9
Inverting Input for Amplifier 3
Noninverting Input for Amplifier 3
Output for Amplifier 4
10
14
13
12
IN3+
OUT4
IN4-
Inverting Input for Amplifier 4
Noninverting Input for Amplifier 4
IN4+
8
_______________________________________________________________________________________
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
3.5kΩ
R
L
C
L
LMX321
LMX358
LMX324
3.5kΩ
Figure 3. Capacitive-Load-Driving Circuit
Figure 1. Input Protection Circuit
V
= 5V, V = 0, C = 2.2nF
EE L
CC
V
IN
2V/div
R = 2kΩ
L
2.6V
2.4V
V
IN
100mV/div
2.5V
V
OUT
1V/div
2.6V
2.4V
V
OUT
100mV/div
-2.5V
4µs/div
200µs/div
= 2.5V, V = -2.5V, A = 2V/V
V
CC
EE
VCL
Figure 4. Output With Excessive Capacitive Load
Figure 2. Rail-to-Rail Output Swing
shows the output voltage swing of the LMX321 config-
ured with A = +2V/V.
Detailed Description
VCL
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 volt-
ages (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 cur-
rent can be approximated by the following equation:
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.
I
= (V
- 1.8V) / 7kΩ
BIAS
DIFF
In the region where the differential input voltage
approaches 1.8V, input resistance decreases exponen-
tially from 3MΩ to 7kΩ as the diode block begins con-
ducting. Inversely, the bias current increases with the
same curve.
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.
Rail-to-Rail Output Stage
The LMX321/LMX358/LMX324 drive 2kΩ loads and still
typically swing within 40mV of the supply rails. Figure 2
_______________________________________________________________________________________
9
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 V
possible.
as
CC
R
ISO
C
L
Good layout techniques optimize performance by mini-
mizing 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 capaci-
tance.
LMX321
LMX358
LMX324
Figure 5. Capacitive-Load-Driving Circuit With Isolation
Resistor
Chip Information
LMX321 TRANSISTOR COUNT: 88
LMX358 TRANSISTOR COUNT: 175
LMX324 TRANSISTOR COUNT: 349
PROCESS: Bipolar
V
CC
2V/div
V
OUT
1V/div
4µs/div
Figure 6. Power-Up/Power-Down Waveform
Selector Guide
AMPLIFIERS PER
PART
TOP MARK
PACKAGE
LMX321AXK-T
LMX321AUK-T
LMX358AKA-T
LMX358ASA
LMX358AUA
LMX324ASD
LMX324AUD
1
1
2
2
2
4
4
ACP
ADSQ
AAIR
—
—
—
—
10 ______________________________________________________________________________________
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Package Information
______________________________________________________________________________________ 11
Single/Dual/Quad, General-Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Package Information (continued)
12 ______________________________________________________________________________________
Single/Dual/Quad, General Purpose,
Low-Voltage, Rail-to-Rail Output Op Amps
Package Information (continued)
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.
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