MP8110
Precision High-Side
Current-Sense Amplifier
The Future of Analog IC Technology
DESCRIPTION
The MP8110 is a low-cost, precision, high-side
current-sense amplifier. This device operates
from a single 2.5V to 40V supply and typically
consumes 12µA. It is ideal for today’s notebook
computers, cell phones and other systems
where battery/DC current monitoring is critical.
High-side current monitoring is especially useful
in battery-powered systems since it does not
interfere with the ground path of the battery
charger. The input common-mode range of
1.4V to 40V is independent of the supply
voltage and ensures that the current-sense
feedback remains viable even when connected
to a 2-cell battery pack in deep discharge.
This device is available in 8-pin SOIC and
MSOP packages.
FEATURES
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Low-Cost, Compact Current-Sense Solution
12µA Typical Supply Current
2.5V to 40V Operating Supply Voltage
1.4V to 40V Input Common Mode Range
3µA Typical Shutdown Current
400µV Input Offset Voltage
High Current Sensing Capability
Integrated Buffer Amplifier
Available in 8-Pin SOIC and MSOP packages,
Portable PCs
PDA’s
Smart Battery Packs
Cell Phones
Portable Test/Measurement Systems
Battery-Operated Systems
Energy Management Systems
APPLICATIONS
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
V
IN
+
10uF
I
LOAD
RG1
VCC
RG2
C
5
0.1uF
SHUTDOWN
ON OFF
MP8110
OUT2
OUT1
SHDN
GND
C
GS
100pF
C
OUT
Opt.
MP8110 Rev. 0.9
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
1
MP8110 – PRECISION HIGH-SIDE CURRENT-SENSE AMPLIFIER
PACKAGE REFERENCE
TOP VIEW
SHDN
NC
RG1
GND
1
2
3
4
8
7
6
5
OUT2
VCC
RG2
OUT1
TOP VIEW
SHDN
NC
RG1
GND
1
2
3
4
8
7
6
5
OUT2
VCC
RG2
OUT1
Part Number*
MP8110DS
*
Package
SOIC8
Temperature
–40°C to +85°C
Part Number*
MP8110DK
*
Package
MSOP8
Temperature
–40°C to +85°C
For Tape & Reel, add suffix –Z (eg. MP8110DS–Z)
For RoHS Compliant Packaging, add suffix –LF
(eg. MP8110DS–LF–Z)
For Tape & Reel, add suffix –Z (eg. MP8110DK–Z)
For RoHS Compliant Packaging, add suffix –LF
(eg. MP8110DK–LF–Z)
ABSOLUTE MAXIMUM RATINGS
(1)
VCC, RG1, RG2 to GND..............–0.3V to +42V
Max Differential Input Voltage, RG1 to RG2..... 5V
Max Junction Temperature (T
j
) ................150°C
Storage Temperature ............. –65°C to +150°C
Thermal Resistance
(3)
SOIC8..................................... 90 ...... 42...
°C/W
MSOP8 .................................. 150 ..... 65...
°C/W
Continuous Power Dissipation
(T
A
=70°C) ...............................................800mW
Notes:
1) Exceeding these ratings may damage the device.
2) The device is not guaranteed to function outside of its
operating conditions.
3) Measured on approximately 1” square of 1 oz copper.
θ
JA
θ
JC
Recommended Operating Conditions
(2)
V
CC
, RG1, RG2 to GND ...................2.5V to 40V
Operating Ambient Temperature–40°C to +85°C
ELECTRICAL CHARACTERISTICS
V
CC
= 24V, V
SHDN
= 0V, T
A
= +25°C, unless otherwise noted.
Parameter
Supply Voltage
Supply Current
Common Mode Input Voltage
OUT1 Input Offset Voltage
OUT2 Input Offset Voltage
Input Bias Current
(4)
OUT1 Current Accuracy
No-Load OUT1 Error
Low-Level OUT1 Error
No-Load OUT2 Error
Low-Level OUT2 Error
Power Supply Rejection Ratio
Shutdown Supply Current
Symbol
V
CC
I
CC
V
IN_CM
V
OS1
V
OS2
I
RG1
, I
RG2
I
RG1
/I
GS
V
SENSE
= 100mV
V
SENSE
= 0V
V
SENSE
= 5mV
V
SENSE
= 0V
V
SENSE
= 5mV
2.5V < V
CC
< 40V,
V
SENSE
= 100mV
V
SHDN
= 3V
I
LOAD
= 0A, V
CC
= 40V
V
CC
> V
IN
Low
V
CC
> V
IN
High
Conditions
Min
2.5
12
1.4
40
0.4
1
4
±2
0.1
0.3
0.01
0.05
70
97
3
6
2
5
20
±5
1
2
1
2
mV
mV
nA
%
µA
µA
µA
µA
dB
µA
Typ
Max
40
30
Units
V
µA
V
PSRR
I
CC(SHDN)
MP8110 Rev. 0.9
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
2
MP8110 – PRECISION HIGH-SIDE CURRENT-SENSE AMPLIFIER
ELECTRICAL CHARACTERISTICS
(continued)
V
CC
= 24V, V
SHDN
= 0V, T
A
= +25°C, unless otherwise noted.
Parameter
SHDN Threshold Voltage
SHDN Hysteresis
t
R
OUT1 Rise, Fall Time
(4)
t
F
V
SENSE
= 40mV,
R
GS
= 20kΩ,
R
OUT
= 100kΩ,
R
G1
= R
G2
= 2kΩ,
C
GS
= 100pF,
C
OUT
= 100pF, 10% to 90%
V
SENSE
= 40mV,
R
GS
= 20kΩ,
R
OUT
= 100kΩ,
R
G1
= R
G2
= 2kΩ,
C
GS
= 100pF,
C
OUT
= 100pF, 10% to 90%
Symbol
Conditions
Min
0.7
Typ
0.9
30
17
Max
1.2
Units
V
mV
µs
V
TH_SHUTDOWN
(Low - High)
29
t
R
OUT2 Rise, Fall Time
(4)
t
F
OUT1 Output Voltage
Range
OUT2 Output Voltage
Range
Maximum OUT1 Current
(4)
Maximum OUT2 Current
(4)
V
GS
V
OUT
I
GS
I
OUT2
18
µs
26
V
CC
– 0.15
V
CC
– 1
500
5
24
24
V
V
µA
mA
Notes:
4) Guaranteed by design.
5) Input common mode range cannot exceed the supply voltage.
PIN FUNCTIONS
SOIC8
1
2
3
4
5
6
7
8
Name
SHDN
NC
RG1
GND
OUT1
RG2
VCC
OUT2
Description
Shutdown. Connect to ground for normal operation. When high, supply current is less
than 3µA.
Not Connected.
Gain Resistor. Connect to battery side of current-sense resistor through the gain
resistor.
Ground or Battery Negative Terminal.
Output for Driving Resistor Load.
Gain Resistor. Connect to load side of current-sense resistor through the gain
resistor.
Power Input. Connect to Battery Input.
Output For Driving Capacitive Loads.
MP8110 Rev. 0.9
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
3
MP8110 – PRECISION HIGH-SIDE CURRENT-SENSE AMPLIFIER
OPERATION
The MP8110 is a current-sense amplifier with a
wide operating input voltage range of 2.5V to
40V.It has 1.4V to 40V Common-Mode range.
This feature allows the monitoring of current
flow out of a battery in deep discharge, and also
enables high-side current sensing up to the
supply voltage, V
CC
. Current flows through the
sense resistor, R
S
, which generates a sense
voltage V
RS
. The high precision sense amplifier
built into the MP8110 monitors the differential
voltage across R
S
and dynamically adjusts the
gate voltage of the internal P-channel MOSFET
to maintain a equal passing current as I
RG1
. The
current amplifier gain is therefore set as: R
GS
/
R
G1
.
Choosing Sensing Resistor
Given the gain and maximum load current,
select R
S
such that V
RS
does not exceed
+0.25V and V
OUT1
does not exceed 5V. To
measure lower currents more accurately, use a
high value for Rs. A higher value develops a
higher sense voltage, which overcomes offset
voltage errors of the internal current amplifier.
In applications of monitoring very high current,
ensure R
S
is able to dissipate its own I
2
R
losses. If the resistor rating power is exceeded,
its value may drift or it may fail altogether,
causing a differential voltage across the
terminals in excess of the absolute maximum
range (0.25V).
MP8110 Rev. 0.9
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
4
MP8110 – PRECISION HIGH-SIDE CURRENT-SENSE AMPLIFIER
SHDN
BIAS +
ENABLE
--
BUFFER
+
OUT2
NC
I
LOAD
R
G1
R
S
I
RG1
V
RS
R
G2
RG2
VCC
GND
RG1
--
+
SENSE
AMPLIFIER
OUT1
I
RGS
V
OUT1
R
GS
To Load
Figure 1—Functional Block Diagram
APPLICATION INFORMATION
COMPONENT SELECTION
Table 1—Suggested Component Values
(refer to Typical Circuit on page 1)
Full-Scale Load
Current, I
SENSE
(A)
0.1
1
5
10
Current Sense
Resistor (mΩ)
500
50
10
5
Gain Setting Resistor
(kΩ) (R
G1
= R
G2
)
2
2
2
2
R
GS
(kΩ)
20
20
20
20
Gain
10
10
10
10
The value of V
OUT1
can be obtained with the equation:
V
OUT 1
=
I
LOAD
×
R
S
×
R
GS
=
I
LOAD
×
R
S
×
Gain
R
G1
Where R
G1
is the sense resistor and I
LOAD
is the load current.
MP8110 Rev. 0.9
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
5
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