LMP8277
High Common Mode, Gain of 14, Precision Voltage
Difference Amplifier
General Description
The LMP8277 is a fixed gain differential amplifier with a 2V
to 27V input common mode voltage range and a supply
voltage range of 4.75V to 5.5V. The LMP8277 is part of the
LMP
TM
precision amplifier family which will detect, amplify
and filter small differential signals in the presence of high
common mode voltages. The gain is fixed at 14 and is
adequate to drive an ADC to full scale in most cases. This
fixed gain is achieved in two separate stages, a preamplifier
with gain of +7 and a second stage amplifier with a gain of
+2. The internal signal path between these two stages is
brought out on two pins that provide a connection for a filter
network.
The LMP8277 will operate with reduced specifications over
the extended common mode input voltage range of -2V to
36V. This feature makes the device suitable for applications
with load dump in automotive systems.
Features
Typical Values, T
A
= 25C
n
Input offset voltage
2 mV max
n
TCVos
30 V/C max
n
CMRR
80 dB min
n
Extended CMVR
-2V to 36V
n
Output voltage swing
Rail-to-rail
n
Bandwidth
80 kHz
n
Operating temperature range (ambient)
-40C to 125C
n
Supply voltage
4.75V to 5.5V
n
Supply current
1 mA
Applications
n
Fuel injection control
n
High and low side driver configuration current sensing
n
Power management systems
Typical Application
Low Side Current Sensing
20130901
LMP
TM
is a trademark of National Semiconductor Corporation.
December 2005
LMP8277
High
Common
Mode,
Gain
of
14,
Precision
V
oltage
Difference
Amplifier
2005 National Semiconductor Corporation
DS201309
www.national.com
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
ESD Tolerance (Note 2)
Human Body Model
For input pins only
4000V
For All other pins
2000V
Machine Model
200V
Supply Voltage (V
S
GND)
5.75V
Voltage on +IN and -IN
-5V to 42V
Transient (400 ms)
-7V to 45V
Storage Temperature Range
-65C to +150C
Junction Temperature (Note 3)
+150C max
Soldering Information
Infrared or Convection (20 sec)
235C
Wave Soldering Lead Temp. (10 sec)
260C
Operating Ratings
(Note 1)
Temperature Range
Packaged Devices (Note 3)
-40C to +125C
Supply Voltage (V
S
GND)
4.75V to 5.5V
Package Thermal Resistance (
JA
(Note 3))
8-Pin SOIC
190C/W
8-Pin MSOP
235C/W
5V Electrical Characteristics
(Note 4)
Unless otherwise specified, all limits are guaranteed for T
A
= 25C, V
S
= 5V, GND = 0, -2V
V
CM
27V, R
L
= Open. Bold-
face limits apply at the temperature extremes.
Symbol
Parameter
Conditions
Min
Typ
(Note 5)
Max
Units
V
OS
Input Offset Voltage
V
CM
= V
S
/2
0.25
2.0
mV
TC V
OS
Input Offset Voltage Drift
V
CM
= V
S
/2
25C
T
A
125C
20
30
V/C
-40C
T
A
25C
20
35
A2 I
B
Input Bias Current of A2
(Note 6)
-20
pA
20
nA
I
S
Supply Current
1.0
1.2
1.4
mA
R
CM
Input Impedance Common Mode
160
200
240
k
R
DM
Input Impedance Differential Mode
320
400
480
k
CMVR
Input Common-Mode Voltage
Range
2
+27
V
ECMVR
Extended Common-Mode Voltage
Range
2
36
V
DC
CMRR
DC Common Mode Rejection Ratio 0C
T
A
125C
-2V
V
CM
27V
-2V
V
CM
36V
80
60
97
dB
-40C
T
A
0C
-2V
V
CM
27V
-2V
V
CM
36V
77
60
AC
CMRR
AC Common Mode Rejection Ratio
(Note 7)
-2V
V
CM
27V
f = 1 kHz
80
95
dB
f = 10 kHz
78
PSRR
Power Supply Rejection Ratio
4.75V
V
S
5.5V
70
80
dB
R
F-INT
Filter Resistor
97
100
103
k
TCR
F-INT
Filter Resistor Drift
20
ppm/C
A
V
Total Gain
13.86
14
14.14
V/V
Gain Drift
2
25
ppm/C
A
V1
A1 Gain
6.93
7
7.07
V/V
A
V2
A2 Gain
1.98
2
2.02
V/V
A1 V
OUT
A1 Output Voltage Swing
VOL
0.004
0.01
V
VOH
4.80
4.95
A2 V
OUT
A2 Output Voltage Swing
(Notes 8, 9)
R
L
= 100 k
on Output VOL
0.007
0.02
V
VOH
4.80
4.99
R
L
= 10 k
on Output VOL
0.03
V
VOH
4.95
SR
Slew Rate (Note 10)
0.7
V/s
LMP8277
www.national.com
2
5V Electrical Characteristics
(Note 4)
(Continued)
Unless otherwise specified, all limits are guaranteed for T
A
= 25C, V
S
= 5V, GND = 0, -2V
V
CM
27V, R
L
= Open. Bold-
face limits apply at the temperature extremes.
Symbol
Parameter
Conditions
Min
Typ
(Note 5)
Max
Units
BW
Bandwidth
80
kHz
Noise
0.1 Hz to 10 Hz
3.82
V
PP
Spectral Density
f = 1 kHz
486
nV/
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics Tables.
Note 2: Human Body Model is 1.5 k
in series with 100 pF. Machine Model is 0 in series with 200 pF.
Note 3: The maximum power dissipation is a function of T
J(MAX)
,
JA
, and T
A
. The maximum allowable power dissipation at any ambient temperature is
P
D
= (T
J(MAX)
- T
A
)/
JA
. All numbers apply for packages soldered directly onto a PC board.
Note 4: Electrical table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of
the device.
Note 5: Typical values represent the parametric norm at the time of characterization.
Note 6: Positive current corresponds to current flowing into the device.
Note 7: AC Common Mode Signal is a 24 V
PP
sine-wave (0V to 24V) at the given frequency
Note 8: For VOL, R
L
is connected to V
S
and for VOH, R
L
is connected to GND.
Note 9: For this test input is driven from A1 stage.
Note 10: Slew rate is the average of the rising and falling slew rates.
Connection Diagram
8-Pin SOIC/MSOP
20130902
Top View
Ordering Information
Package
Part Number
Package Marking
Transport Media
NSC Drawing
8-Pin SOIC
LMP8277MA
LMP8277MA
95 Units/Rail
M08A
LMP8277MAX
2.5k Units Tape and Reel
8-Pin MSOP
LMP8277MM
LMP8277MM
95 Units/Rail
MUA08A
LMP8277MMX
2.5k Units Tape and Reel
LMP8277
www.national.com
3
Typical Performance Characteristics
Unless otherwise specified: T
A
= 25C, V
S
= 5V, V
CM
= V
S
/2
V
OS
vs. V
CM
Over Temperature
Typical V
OS
vs. Temperature
20130915
20130921
Input Bias Current Over Temperature (A1 Inputs)
Input Bias Current Over Temperature (A2 Inputs)
20130919
20130918
Input Bias Current Over Temperature (A2 Inputs)
Input Referred Voltage Noise vs. Frequency
20130920
20130906
LMP8277
www.national.com
4
Typical Performance Characteristics
Unless otherwise specified: T
A
= 25C, V
S
= 5V, V
CM
= V
S
/2
(Continued)
PSRR vs. Frequency
V
OS
vs. Supply Voltage
20130923
20130922
Gain vs. Frequency Over Temperature
Gain vs. Frequency Over Temperature
20130912
20130911
Filter Resistor
CMRR vs. Frequency
20130917
20130914
LMP8277
www.national.com
5
PDF 
ZIP