LTC6101/LTC6101HV
1
6101fa
TO µP
6101 TA01
LTC2433-1
LTC6101HV
ROUT
4.99k
RIN
100Ω
VOUT
52
1
34
VSENSE
ILOAD
5V TO 105V
1µF
5V
L
O
A
D
–+
–
+
VOUT = • VSENSE = 49.9VSENSE
ROUT
RIN
TYPICAL APPLICATIO
U
APPLICATIO S
U
FEATURES
DESCRIPTIO
U
■
Current Shunt Measurement
■
Battery Monitoring
■
Remote Sensing
■
Power Management
16-Bit Resolution Unidirectional Output into LTC2433 ADC
High Voltage,
High-Side Current Sense
Amplifier in SOT-23
■
Supply Range:
5V to 100V, 105V Absolute Maximum (LTC6101HV)
4V to 60V, 70V Absolute Maximum (LTC6101)
■
Low Offset Voltage: 300µµ
µµ
µV Max
■
Fast Response: 1µµ
µµ
µs Response Time (0V to 2.5V on
a 5V Output Step)
■
Gain Configurable with 2 Resistors
■
Low Input Bias Current: 170nA Max
■
PSRR: 110dB Min
4V to 60V (LTC6101)
5V to 100V (LTC6101HV)
■
Output Current: 1mA Max
■
Low Supply Current: 250µA, V
S
= 14V
■
Low Profile (1mm) SOT-23 (ThinSOT
TM
) Package
Step Response
The LTC
®
6101/LTC6101HV are versatile, high voltage, high
side current sense amplifiers. Design flexibility is provided
by the excellent device characteristics; 300µV Max offset
and only 375µA (typical at 60V) of current consumption.
The LTC6101 operates on supplies from 4V to 60V and
LTC6101HV operates on supplies from 5V to 100V.
The LTC6101 monitors current via the voltage across an
external sense resistor (shunt resistor). Internal circuitry
converts input voltage to output current, allowing for a small
sense signal on a high common mode voltage to be trans-
lated into a ground referenced signal. Low DC offset allows
the use of a small shunt resistor and large gain-setting
resistors. As a result, power loss in the shunt is reduced.
The wide operating supply range and high accuracy make
the LTC6101 ideal for a large array of applications from
automotive to industrial and power management. A maxi-
mum input sense voltage of 500mV allows a wide range of
currents to be monitored. The fast response makes the
LTC6101 the perfect choice for load current warnings and
shutoff protection control. With very low supply current,
the LTC6101 is suitable for power sensitive applications.
The LTC6101 is available in 5-lead SOT-23 and 8-lead
MSOP packages.
, LTC and LT are registered trademarks of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
5.5V
5V
0.5V
0V
500ns/DIV
6101 TA01b
T
A
= 25°C
V+ = 12V
R
IN
= 100
R
OUT
= 5k
V
SENSE
+ = V+
V
OUT
V
SENSE
–
∆V
SENSE
– = 100mV
I
OUT
= 100µA
I
OUT
= 0
LTC6101/LTC6101HV
2
6101fa
PACKAGE/ORDER I FOR ATIO
UUW
ABSOLUTE AXI U RATI GS
W
WW
U
(Note 1)
Total Supply Voltage (V
+
to V
–
)
LTC6101 ............................................................. 70V
LTC6101HV ...................................................... 105V
Minimum Input Voltage (–IN Pin) ................... (V
+
– 4V)
Maximum Output Voltage (Out Pin)........................... 9V
Input Current ..................................................... ±10mA
Output Short-Circuit Duration (to V
–
) ............. Indefinite
Operating Temperature Range
LTC6101C/LTC6101HVC .................... – 40°C to 85°C
LTC6101ACMS8
LTC6101AIMS8
LTC6101AHMS8
LTC6101HVACMS8
LTC6101HVAIMS8
LTC6101HVAHMS8
Consult LTC Marketing for parts specified with wider operating temperature ranges.
*The temperature grades and parametric grades are identified by a label on the shipping container.
ORDER PART NUMBER MS8 PART MARKING*
LTBSB
LTBSB
LTBSB
LTBSX
LTBSX
LTBSX
T
JMAX
= 150°C, θ
JA
= 300°C/ W
LTC6101I/LTC6101HVI ...................... – 40°C to 85°C
LTC6101H/LTC6101HVH ................. – 40°C to 125°C
Specified Temperature Range (Note 2)
LTC6101C/LTC6101HVC ......................... 0°C to 70°C
LTC6101I/LTC6101HVI ...................... – 40°C to 85°C
LTC6101H/LTC6101HVH ................. – 40°C to 125°C
Storage Temperature Range ................ – 65°C to 150°C
Lead Temperature (Soldering, 10 sec)................. 300°C
LTC6101BCS5
LTC6101CCS5
LTC6101BIS5
LTC6101CIS5
LTC6101BHS5
LTC6101CHS5
LTC6101HVBCS5
LTC6101HVCCS5
LTC6101HVBIS5
LTC6101HVCIS5
LTC6101HVBHS5
LTC6101HVCHS5
ORDER PART NUMBER S5 PART MARKING*
LTBND
LTBND
LTBND
LTBND
LTBND
LTBND
LTBSZ
LTBSZ
LTBSZ
LTBSZ
LTBSZ
LTBSZ
T
JMAX
= 150°C, θ
JA
= 250°C/ W
OUT 1
V
–
2
TOP VIEW
S5 PACKAGE
5-LEAD PLASTIC TSOT-23
–IN 3
5 V
+
4 +IN
1
2
3
4
–IN
NC
NC
OUT
8
7
6
5
+IN
V+
NC
V–
TOP VIEW
MS8 PACKAGE
8-LEAD PLASTIC MSOP
Order Options Tape and Reel: Add #TR
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF
Lead Free Part Marketing: http://www.linear.com/leadfree/
LTC6101/LTC6101HV
3
6101fa
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
S
Supply Voltage Range ●460V
V
OS
Input Offset Voltage V
SENSE
= 5mV, Gain = 100, LTC6101A ±85 ±300 µV
V
SENSE
= 5mV, Gain = 100, LTC6101AC, LTC6101AI ●±450 µV
V
SENSE
= 5mV, Gain = 100, LTC6101AH ●±535 µV
V
SENSE
= 5mV, Gain = 100, LTC6101B ±150 ±450 µV
●±810 µV
V
SENSE
= 5mV, Gain = 100, LTC6101C ±400 ±1500 µV
●±2500 µV
∆V
OS
/∆T Input Offset Voltage Drift V
SENSE
= 5mV, LTC6101A ●±1µV/°C
V
SENSE
= 5mV, LTC6101B ●±3µV/°C
V
SENSE
= 5mV, LTC6101C ●±10 µV/°C
I
B
Input Bias Current R
IN
= 1M 100 170 nA
●245 nA
I
OS
Input Offset Current R
IN
= 1M ●±2±15 nA
V
SENSE(MAX)
Input Sense Voltage Full Scale V
OS
within Specification, R
IN
= 1k ●500 mV
PSRR Power Supply Rejection Ratio V
S
= 6V to 60V, V
SENSE
= 5mV, Gain = 100 118 140 dB
●115 dB
V
S
= 4V to 60V, V
SENSE
= 5mV, Gain = 100 110 133 dB
●105 dB
V
OUT
Maximum Output Voltage 12V ≤ V
S
≤ 60V, V
SENSE
= 88mV ●8V
V
S
= 6V, V
SENSE
= 330mV, R
IN
= 1k, R
OUT
= 10k ●3V
V
S
= 4V, V
SENSE
= 550mV, R
IN
= 1k, R
OUT
= 2k ●1V
V
OUT (0)
Minimum Output Voltage V
SENSE
= 0V, Gain = 100, LTC6101A 0 30 mV
V
SENSE
= 0V, Gain = 100, LTC6101AC, LTC6101AI ●45 mV
V
SENSE
= 0V, Gain = 100, LTC6101AH ●53.5 mV
V
SENSE
= 0V, Gain = 100, LTC6101B 0 45 mV
●81 mV
V
SENSE
= 0V, Gain = 100, LTC6101C 0 150 mV
●250 mV
I
OUT
Maximum Output Current 6V ≤ V
S
≤ 60V, R
OUT
= 2k, V
SENSE
= 110mV, Gain = 20 ●1mA
V
S
= 4V, V
SENSE
= 550mV, Gain = 2, R
OUT
= 2k ●0.5 mA
t
r
Input Step Response ∆V
SENSE
= 100mV Transient, 6V ≤ V
S
≤ 60V, Gain = 50 1 µs
(to 2.5V on a 5V Output Step) V
S
= 4V 1.5 µs
BW Signal Bandwidth I
OUT
= 200µA, R
IN
= 100, R
OUT
= 5k 140 kHz
I
OUT
= 1mA, R
IN
= 100, R
OUT
= 5k 200 kHz
I
S
Supply Current V
S
= 4V, I
OUT
= 0, R
IN
= 1M 220 450 µA
●475 µA
V
S
= 6V, I
OUT
= 0, R
IN
= 1M 240 475 µA
●525 µA
V
S
= 12V, I
OUT
= 0, R
IN
= 1M 250 500 µA
●590 µA
V
S
= 60V, I
OUT
= 0, R
IN
= 1M 375 640 µA
LTC6101I, LTC6101C ●690 µA
LTC6101H ●720 µA
ELECTRICAL CHARACTERISTICS
(LTC6101) The ● denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C, RIN = 100Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for
details), 4V ≤ VS ≤ 60V unless otherwise noted.
LTC6101/LTC6101HV
4
6101fa
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
V
S
Supply Voltage Range ●5 100 V
V
OS
Input Offset Voltage V
SENSE
= 5mV, Gain = 100, LTC6101HVA ±85 ±300 µV
V
SENSE
= 5mV, Gain = 100, LTC6101HVAC, LTC6101HVAI ●±450 µV
V
SENSE
= 5mV, Gain = 100, LTC6101HVAH ●±535 µV
V
SENSE
= 5mV, Gain = 100, LTC6101HVB ±150 ±450 µV
●±810 µV
V
SENSE
= 5mV, Gain = 100, LTC6101HVC ±400 ±1500 µV
●±2500 µV
∆V
OS
/∆T Input Offset Voltage Drift V
SENSE
= 5mV, LTC6101HVA ●±1µV/°C
V
SENSE
= 5mV, LTC6101HVB ●±3µV/°C
V
SENSE
= 5mV, LTC6101HVC ●±10 µV/°C
I
B
Input Bias Current R
IN
= 1M 100 170 nA
●245 nA
I
OS
Input Offset Current R
IN
= 1M ●±2±15 nA
V
SENSE(MAX)
Input Sense Voltage Full Scale V
OS
within Specification, R
IN
= 1k ●500 mV
PSRR Power Supply Rejection Ratio V
S
= 6V to 100V, V
SENSE
= 5mV, Gain = 100 118 140 dB
●115 dB
V
S
= 5V to 100V, V
SENSE
= 5mV, Gain = 100 110 133 dB
●105 dB
V
OUT
Maximum Output Voltage 12V ≤ V
S
≤ 100V, V
SENSE
= 88mV ●8V
5V, V
SENSE
= 330mV, R
IN
= 1k, R
OUT
= 10k ●3V
V
OUT (0)
Minimum Output Voltage V
SENSE
= 0V, Gain = 100, LTC6101HVA 0 30 mV
V
SENSE
= 0V, Gain = 100, LTC6101HVAC, LTC6101HVAI ●45 mV
V
SENSE
= 0V, Gain = 100, LTC6101HVAH ●53.5 mV
V
SENSE
= 0V, Gain = 100, LTC6101HVB 0 45 mV
●81 mV
V
SENSE
= 0V, Gain = 100, LTC6101HVC 0 150 mV
●250 mV
I
OUT
Maximum Output Current 5V ≤ V
S
≤ 100V, R
OUT
= 2k, V
SENSE
= 110mV, Gain = 20 ●1mA
t
r
Input Step Response ∆V
SENSE
= 100mV Transient, 6V ≤ V
S
≤ 100V, Gain = 50 1 µs
(to 2.5V on a 5V Output Step) V
S
= 5V 1.5 µs
BW Signal Bandwidth I
OUT
= 200µA, R
IN
= 100, R
OUT
= 5k 140 kHz
I
OUT
= 1mA, R
IN
= 100, R
OUT
= 5k 200 kHz
I
S
Supply Current V
S
= 5V, I
OUT
= 0, R
IN
= 1M 200 450 µA
●475 µA
V
S
= 6V, I
OUT
= 0, R
IN
= 1M 220 475 µA
●525 µA
V
S
= 12V, I
OUT
= 0, R
IN
= 1M 230 500 µA
●590 µA
V
S
= 60V, I
OUT
= 0, R
IN
= 1M 350 640 µA
LTC6101HVI, LTC6101HVC ●690 µA
LTC6101HVH ●720 µA
V
S
= 100V, I
OUT
= 0, R
IN
= 1M 350 640 µA
LTC6101HVI, LTC6101HVC ●690 µA
LTC6101HVH ●720 µA
ELECTRICAL CHARACTERISTICS
(LTC6101HV) The ● denotes the specifications which apply over the full
operating temperature range, otherwise specifications are at TA = 25°C, RIN = 100Ω, ROUT = 10k, VSENSE+ = V+ (see Figure 1 for
details), 5V ≤ VS ≤ 100V unless otherwise noted.
LTC6101/LTC6101HV
5
6101fa
LTC6101: IOUT Maximum vs
Temperature
Input VOS vs Temperature Input VOS vs Supply Voltage Input Sense Range
LTC6101: VOUT Maximum vs
Temperature
LTC6101HV: VOUT Maximum vs
Temperature
44010 20 30 50 10060 70 80 90
VSUPPLY (V)
MAXIMUM VSENSE (V)
2.5
2
1.5
1
0.5
0
6101 G05
TA = 125°C
TA = 85°C
TA = 70°C
TA = 0°CTA = –40°C
RIN = 3k
ROUT = 3k
TA = 25°C
LTC6101
LTC6101HV
TEMPERATURE (°C)
12
10
8
6
4
2
0
–40 40 80 120100–20
6101 G06
020 60
MAXIMUM OUTPUT (V)
V
S
= 60V
V
S
= 12V
V
S
= 6V
V
S
= 4V
TEMPERATURE (°C)
7
6
5
4
3
2
1
0
–40 40 80 120100–20
6101 G07
020 60
MAXIMUM IOUT (mA)
VS = 12V
VS = 60V
VS = 6V
VS = 4V
TYPICAL PERFOR A CE CHARACTERISTICS
UW
V
SUPPLY
(V)
40
20
0
–20
–40
–60
–80
–100
–120
–140
6101 G02
43211 18 25 39 46 53 60
INPUT OFFSET (µV)
R
IN
= 100
R
OUT
= 5k
V
IN
= 5mV T
A
= 125°C
T
A
= 85°C
T
A
= 45°C
T
A
= –40°C
T
A
= 0°C
INPUT OFFSET (µV)
800
600
400
200
0
–200
–400
–600
–800
–1000
6101 G01
TEMPERATURE (°C)
–40 12004080
–20 20 60 100
A GRADE
B GRADE
C GRADE
RIN = 100
ROUT = 5k
VIN = 5mV
REPRESENTATIVE
UNITS
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: The LTC6101C/LTC6101HVC are guaranteed to meet specified
performance from 0°C to 70°C. The LTC6101C/LTC6101HVC are designed,
characterized and expected to meet specified performance from –40°C to
85°C but are not tested or QA sampled at these temperatures. LTC6101I/
LTC6101HVI are guaranteed to meet specified performance from –40°C to
85°C. The LTC6101H/LTC6101HVH are guaranteed to meet specified
performance from –40°C to 125°C.
ELECTRICAL CHARACTERISTICS
TEMPERATURE (°C)
12
10
8
6
4
2
0
–40 40 80 120100–20
6101 G20
020 60
MAXIMUM OUTPUT (V)
VS = 100V
VS = 12V
VS = 5V
VS = 6V
VS = 4V
LTC6101/LTC6101HV
6
6101fa
TYPICAL PERFOR A CE CHARACTERISTICS
UW
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (µA)
450
400
350
300
250
200
150
100
50
0
32
6101 G11
816 48 56
24 40
28
412 44 52
20 36 60
–40°C
0°C
25°C
70°C
85°C
125°C
V
IN
= 0
R
IN
= 1M
V+
V+-10mV
0.5V
0V
TIME (10µs/DIV)
6101 G12
TA = 25°C
V+ = 12V
RIN = 100
ROUT = 5k
VSENSE+ = V+
VSENSE–
VOUT
V
+
-10mV
V
+
-20mV
1V
0.5V
TIME (10µs/DIV)
6101 G13
V
OUT
V
SENSE
–
T
A
= 25°C
V
+
= 12V
R
IN
= 100
R
OUT
= 5k
V
SENSE
+
= V
+
LTC6101: Supply Current vs
Supply Voltage
Step Response 0mV to 10mV Step Response 10mV to 20mV
Input Bias Current vs
Temperature
Gain vs Frequency
GAIN (dB)
FREQUENCY (Hz)
1k
40
35
30
25
20
15
10
5
0
–5
–10 10k 100k 1M
6101 G09
T
A
= 25°C
R
IN
= 100
R
OUT
= 4.99k
I
OUT = 200µA
I
OUT = 1mA
TEMPERATURE (°C)
160
140
120
100
80
60
40
20
0
–40 40 80 120100–20
6101 G10
020 60
I
B
(nA)
V
S
= 6V TO 100V
V
S
= 4V
Output Error Due to Input Offset vs
Input Voltage
LTC6101HV: IOUT Maximum vs
Temperature
INPUT VOLTAGE (V)
0.1
OUTPUT ERROR (%)
1
10
100
0 0.2 0.3 0.4
0.01
0.1 0.50.15 0.25 0.350.05 0.45
6101 G08
C GRADE
B GRADE
A GRADE
TA = 25°C
GAIN =10
TEMPERATURE (°C)
7
6
5
4
3
2
1
0
–40 40 80 120100–20
6101 G21
020 60
MAXIMUM I
OUT
(mA)
V
S
= 12V
V
S
= 100V
V
S
= 6V
V
S
= 5V
V
S
= 4V
LTC6101HV: Supply Current vs
Supply Voltage
SUPPLY VOLTAGE (V)
0
SUPPLY CURRENT (µA)
600
500
400
300
200
100
0
6101 G22
60
10 3020 40 80 90
50 70 100
–40°C0°C
85°C
125°C
V
IN
= 0
R
IN
= 1M
70°C
25°C
LTC6101/LTC6101HV
7
6101fa
FREQUENCY (Hz)
PSRR (dB)
0.1 1 10 100 1k 10k 100k 1M
6101 G19
160
140
120
100
80
60
40
20
0
R
IN
= 100
R
OUT
= 10k
C
OUT
= 5pF
GAIN = 100
I
OUTDC
= 100µA
V
INAC
= 50mVp
LTC6101HV,
V
+
= 5V
LTC6101,
LTC6101HV,
V
+
= 12V
LTC6101,
V
+
= 4V
TYPICAL PERFOR A CE CHARACTERISTICS
UW
V
+
V
+
-100mV
5V
0V
TIME (10µs/DIV)
6101 G14
VOUT
CLOAD = 1000pF
CLOAD = 10pF
VSENSE
–
TA = 25°C
V
+
= 12V
RIN = 100
ROUT = 5k
VSENSE
+
= V
+
V
+
V
+
-100mV
5V
0V
TIME (100µs/DIV)
6101 G15
VOUT
VSENSE
–
TA = 25°C
V
+
= 12V
CLOAD = 2200pF
RIN = 100
ROUT = 5k
VSENSE
+
= V
+
5.5V
5V
0.5V
0V
TIME (500ns/DIV)
6101 G16
V
OUT
V
SENSE
–
∆V
SENSE
–
=100mV
I
OUT
= 100µA
I
OUT
= 0
T
A
= 25°C
V
+
= 12V
R
IN
= 100
R
OUT
= 5k
V
SENSE
+
= V
+
5.5V
5V
0.5V
0V
TIME (500ns/DIV)
6101 G17
V
OUT
∆V
SENSE
– =100mV
I
OUT
= 100µ
I
OUT
= 0
T
A
= 25°C
V+ = 12V
R
IN
= 100
R
OUT
= 5k
V
SENSE
+ = V+
Step Response Falling Edge
Step Response 100mV Step Response 100mV Step Response Rising Edge
PSRR vs Frequency
LTC6101/LTC6101HV
8
6101fa
OUT (Pin 1): Current Output. OUT (Pin 1) will source a
current that is proportional to the sense voltage into an
external resistor.
V
–
(Pin 2): Negative Supply (or Ground for Single-Supply
Operation).
IN
–
(Pin 3): The internal sense amplifier will drive IN
–
(Pin
3) to the same potential as IN
+
(Pin 4). A resistor (R
IN
) tied
from V
+
to IN
–
sets the output current I
OUT
= V
SENSE
/R
IN
.
V
SENSE
is the voltage developed across the external R
SENSE
(Figure 1).
IN
+
(Pin 4): Must be tied to the system load end of the
sense resistor, either directly or through a resistor.
V
+
(Pin 5): Positive Supply Pin. Supply current is drawn
through this pin. The circuit may be configured so that
the LTC6101 supply current is or is not monitored along
with the system load current. To monitor only system
load current, connect V
+
to the more positive side of the
sense resistor. To monitor the total current, including the
LTC6101 current, connect V
+
to the more negative side of
the sense resistor.
Figure 1. LTC6101/LTC6101HV Block Diagram and Typical Connection
The LTC6101 high side current sense amplifier (Figure 1)
provides accurate monitoring of current through a user-
selected sense resistor. The sense voltage is amplified by
a user-selected gain and level shifted from the positive
power supply to a ground-referred output. The output
signal is analog and may be used as is or processed with
an output filter.
Theory of Operation
An internal sense amplifier loop forces IN
–
to have the
same potential as IN
+
. Connecting an external resistor,
R
IN
, between IN
–
and V
+
forces a potential across R
IN
that
is the same as the sense voltage across R
SENSE
. A corre-
sponding current, V
SENSE
/R
IN
, will flow through R
IN
. The
high impedance inputs of the sense amplifier will not
conduct this input current, so it will flow through an
internal MOSFET to the output pin.
The output current can be transformed into a voltage by
adding a resistor from OUT to V
–
. The output voltage is
then V
O
= V
–
+ I
OUT
• R
OUT
.
–
+
4
3
5
2
1
IN
–
V
+
V
–
10V OUT
6101 BD
IN
+
LTC6101/LTC6101HV
V
BATTERY
I
OUT
V
SENSE
R
SENSE
I
LOAD
R
OUT
R
IN
–
+
L
O
A
D
V
OUT
= V
SENSE
x R
OUT
R
IN
5k
5k
10V
UU
U
PI FU CTIO S
BLOCK DIAGRA
W
APPLICATIO S I FOR ATIO
WUUU
LTC6101/LTC6101HV
9
6101fa
Figure 2. Kelvin Input Connection Preserves
Accuracy Despite Large Load Current
APPLICATIO S I FOR ATIO
WUUU
LTC6101
ROUT
VOUT
6101 F02
3
5
4
2
1
RIN
V+
LOAD
RSENSE
–
+
Useful Gain Configurations
Gain R
IN
R
OUT
V
SENSE
at V
OUT
= 5V I
OUT
at V
OUT
= 5V
20 499 10k 250mV 500µA
50 200 10k 100mV 500µA
100 100 10k 50mV 500µA
Selection of External Current Sense Resistor
The external sense resistor, R
SENSE
, has a significant
effect on the function of a current sensing system and
must be chosen with care.
First, the power dissipation in the resistor should be
considered. The system load current will cause both heat
and voltage loss in R
SENSE
. As a result, the sense resistor
should be as small as possible while still providing the
input dynamic range required by the measurement. Note
that input dynamic range is the difference between the
maximum input signal and the minimum accurately repro-
duced signal, and is limited primarily by input DC offset of
the internal amplifier of the LTC6101. In addition, R
SENSE
must be small enough that V
SENSE
does not exceed the
maximum input voltage specified by the LTC6101, even
under peak load conditions. As an example, an application
may require that the maximum sense voltage be 100mV.
If this application is expected to draw 2A at peak load,
R
SENSE
should be no more than 50mΩ.
Once the maximum R
SENSE
value is determined, the mini-
mum sense resistor value will be set by the resolution or
dynamic range required. The minimum signal that can be
accurately represented by this sense amp is limited by the
input offset. As an example, the LTC6101B has a typical
input offset of 150µV. If the minimum current is 20mA, a
sense resistor of 7.5mΩ will set V
SENSE
to 150µV. This is
the same value as the input offset. A larger sense resistor
will reduce the error due to offset by increasing the sense
voltage for a given load current.
Choosing a 50mΩ R
SENSE
will maximize the dynamic
range and provide a system that has 100mV across the
sense resistor at peak load (2A), while input offset causes
an error equivalent to only 3mA of load current.
Peak dissipation is 200mW. If a 5mΩ sense resistor is
employed, then the effective current error is 30mA, while
the peak sense voltage is reduced to 10mV at 2A, dissipat-
ing only 20mW.
The low offset and corresponding large dynamic range of
the LTC6101 make it more flexible than other solutions in
this respect. The 150µV typical offset gives 60dB of
dynamic range for a sense voltage that is limited to 150mV
max, and over 70dB of dynamic range if the rated input
maximum of 500mV is allowed.
Sense Resistor Connection
Kelvin connection of the IN
–
and IN
+
inputs to the sense
resistor should be used in all but the lowest power appli-
cations. Solder connections and PC board interconnec-
tions that carry high current can cause significant error in
measurement due to their relatively large resistances. One
10mm x 10mm square trace of one-ounce copper is
approximately 0.5mΩ. A 1mV error can be caused by as
little as 2A flowing through this small interconnect. This
will cause a 1% error in a 100mV signal. A 10A load current
in the same interconnect will cause a 5% error for the same
100mV signal. By isolating the sense traces from the high-
current paths, this error can be reduced by orders of
magnitude. A sense resistor with integrated Kelvin sense
terminals will give the best results. Figure 2 illustrates the
recommended method.
LTC6101/LTC6101HV
10
6101fa
6101 F03b
–+
–+
–
+
R5
7.5k
VIN
301301
VOUT
ILOAD
5
1
3
LTC6101
2
4
RSENSE LO
100m
M1
Si4465
10k
CMPZ4697
7.5k
VIN
1.74M
4.7k
Q1
CMPT5551
40.2k
3
4
5
6
12
8
7
619k
HIGH
RANGE
INDICATOR
(ILOAD > 1.2A)
VLOGIC
(3.3V TO 5V)
LOW CURRENT RANGE OUT
2.5V/A
(
VLOGIC +5V
)
≤ VIN ≤ 60V
0 ≤ ILOAD ≤ 10A
HIGH CURRENT RANGE OUT
250mV/A
301 301
5
1
3
LTC6101
2
4
RSENSE HI
10m
VLOGIC
BAT54C
LTC1540
Selection of External Input Resistor, R
IN
The external input resistor, R
IN
, controls the transcon-
ductance of the current sense circuit. Since I
OUT
= V
SENSE
/
R
IN
, transconductance g
m
= 1/R
IN
. For example, if R
IN
=
100, then I
OUT
= V
SENSE
/100 or I
OUT
= 1mA for V
SENSE
=
100mV.
R
IN
should be chosen to allow the required resolution while
limiting the output current. At low supply voltage, I
OUT
may
be as much as 1mA. By setting R
IN
such that the largest
expected sense voltage gives I
OUT
= 1mA, then the maxi-
mum output dynamic range is available. Output dynamic
range is limited by both the maximum allowed output
current and the maximum allowed output voltage, as well
as the minimum practical output signal. If less dynamic
range is required, then R
IN
can be increased accordingly,
reducing the max output current and power dissipation.
If low sense currents must be resolved accurately in a
system that has very wide dynamic range, a smaller R
IN
than
the max current spec allows may be used if the max
current is limited in another way, such as with a Schottky
diode across R
SENSE
(Figure 3a). This will reduce the high
current measurement accuracy by limiting the result, while
increasing the low current measurement resolution.
Figure 3b. Dual LTC6101s Allow High-Low Current Ranging
APPLICATIO S I FOR ATIO
WUUU
V
+
LOAD
D
SENSE
6101 F03a
R
SENSE
Figure 3a. Shunt Diode Limits Maximum Input Voltage to Allow
Better Low Input Resolution Without Overranging
This approach can be helpful in cases where occasional
large burst currents may be ignored. It can also be used in
a multirange configuration where a low current circuit is
added to a high current circuit (Figure 3b). Note that a
comparator (LTC1540) is used to select the range, and
transistor M1 limits the voltage across R
SENSE LO
.
Care should be taken when designing the board layout for
R
IN,
especially for small R
IN
values. All trace and intercon-
nect impedances will increase the effective R
IN
value,
causing a gain error. In addition, internal device resistance
will add approximately 0.2Ω to R
IN
.
LTC6101/LTC6101HV
11
6101fa
Selection of External Output Resistor, R
OUT
The output resistor, R
OUT
, determines how the output
current is converted to voltage. V
OUT
is simply I
OUT
• R
OUT
.
In choosing an output resistor, the max output voltage
must first be considered. If the circuit that is driven by the
output does not limit the output voltage, then R
OUT
must
be chosen such that the max output voltage does not
exceed the LTC6101 max output voltage rating. If the
following circuit is a buffer or ADC with limited input range,
then R
OUT
must be chosen so that I
OUT(MAX)
• R
OUT
is less
than the allowed maximum input range of this circuit.
In addition, the output impedance is determined by R
OUT
.
If the circuit to be driven has high enough input imped-
ance, then almost any useful output impedance will be
acceptable. However, if the driven circuit has relatively low
input impedance, or draws spikes of current, such as an
ADC might do, then a lower R
OUT
value may be required in
order to preserve the accuracy of the output. As an
example, if the input impedance of the driven circuit is 100
times R
OUT
, then the accuracy of V
OUT
will be reduced by
1% since:
VI
RR
RR
IR IR
OUT OUT OUT IN DRIVEN
OUT IN DRIVEN
OUT OUT OUT OUT
=+
==
••
•• .••
()
()
100
101 099
Error Sources
The current sense system uses an amplifier and resistors
to apply gain and level shift the result. The output is then
dependent on the characteristics of the amplifier, such as
gain and input offset, as well as resistor matching.
Ideally, the circuit output is:
VV R
RVRI
OUT SENSE OUT
IN SENSE SENSE SENSE
==•; •
In this case, the only error is due to resistor mismatch,
which provides an error in gain only. However, offset
voltage, bias current and finite gain in the amplifier cause
additional errors:
Output Error, E
OUT
, Due to the Amplifier DC Offset
Voltage, V
OS
E
OUT(VOS)
= V
OS
• (R
OUT
/R
IN
)
The DC offset voltage of the amplifier adds directly to the
value of the sense voltage, V
SENSE
. This is the dominant
error of the system and it limits the available dynamic
range. The paragraph “Selection of External Current Sense
Resistor” provides details.
Output Error, E
OUT
, Due to the Bias Currents,
I
B
(+) and I
B
(–)
The bias current I
B
(+) flows into the positive input of the
internal op amp. I
B
(–) flows into the negative input.
E
OUT(IBIAS)
= R
OUT
((I
B
(+) • (R
SENSE
/R
IN
) – I
B
(–))
Since I
B
(+) ≈ I
B
(–) = I
BIAS
, if R
SENSE
<< R
IN
then,
E
OUT(IBIAS)
≈ –R
OUT
• I
BIAS
For instance if I
BIAS
is 100nA and R
OUT
is 1kΩ, the output
error is 0.1mV.
Note that in applications where R
SENSE
≈ R
IN
, I
B
(+) causes
a voltage offset in R
SENSE
that cancels the error due to
I
B
(–) and E
OUT(IBIAS)
≈ 0. In applications where R
SENSE
<
R
IN
, the bias current error can be similarly reduced if an
external resistor R
IN
(+) = (R
IN
– R
SENSE
) is connected as
shown in Figure 4 below. Under both conditions:
E
OUT(IBIAS)
= ± R
OUT
• I
OS
; I
OS
= I
B
(+) – I
B
(–)
APPLICATIO S I FOR ATIO
WUUU
LTC6101
ROUT
VOUT
6101 F04
RIN
–
V+
LOAD
RSENSE
3
5
4
2
1
RIN
+
–
+
RIN
+ =
RIN
– –
RSENSE
Figure 4. Second Input R Minimizes
Error Due to Input Bias Current
LTC6101/LTC6101HV
12
6101fa
If the offset current, I
OS
, of the LTC6101 amplifier is 2nA,
the 100 microvolt error above is reduced to 2 microvolts.
Adding R
IN+
as described will maximize the dynamic range
of the circuit. For less sensitive designs, R
IN+
is not
necessary.
Example:
If an I
SENSE
range = (1A to 1mA) and (V
OUT
/I
SENSE
) =
3V/1A
Then, from the Electrical Characteristics of the LTC6101,
R
SENSE
≈ V
SENSE
(max) / I
SENSE
(max) = 500mV/1A =
500mΩ
Gain = R
OUT
/R
IN
= V
OUT
(max) / V
SENSE
(max) = 3V/500mV
= 6
If the maximum output current, I
OUT
, is limited to 1mA,
R
OUT
equals 3V/1mA ≈ 3.01 kΩ (1% value) and R
IN
= 3kΩ/
6 ≈ 499Ω (1% value).
The output error due to DC offset is ±900µVolts (typ) and
the error due to offset current, I
OS
is 3k x 2nA = ±6µVolts
(typical), provided R
IN+
= R
IN–
.
The maximum output error can therefore reach ±906µVolts
or 0.03% (–70dB) of the output full scale. Considering the
system input 60dB dynamic range (I
SENSE
= 1mA to 1A),
the 70dB performance of the LTC6101 makes this applica-
tion feasible.
Output Error, E
OUT
, Due to the Finite DC Open Loop
Gain, A
OL
, of the LTC6101 Amplifier
This errors is inconsequential as the A
OL
of the LTC6101
is very large.
Output Current Limitations Due to Power Dissipation
The LTC6101 can deliver up to 1mA continuous current to
the output pin. This current flows through R
IN
and enters
the current sense amp via the IN(–) pin. The power
dissipated in the LTC6101 due to the output signal is:
P
OUT
= (V
–IN
– V
OUT
) • I
OUT
Since V
–IN
≈ V
+
, P
OUT
≈ (V
+
– V
OUT
) • I
OUT
There is also power dissipated due to the quiescent supply
current:
P
Q
= I
DD
• V
+
The total power dissipated is the output dissipation plus
the quiescent dissipation:
P
TOTAL
= P
OUT
+ P
Q
At maximum supply and maximum output current, the
total power dissipation can exceed 100mW. This will
cause significant heating of the LTC6101 die. In order to
prevent damage to the LTC6101, the maximum expected
dissipation in each application should be calculated. This
number can be multiplied by the θ
JA
value listed in the
package section on page 2 to find the maximum expected
die temperature. This must not be allowed to exceed
150°C, or performance may be degraded.
As an example, if an LTC6101 in the S5 package is to be run
at 55V ±5V supply with 1mA output current at 80°C:
P
Q(MAX)
= I
DD(MAX)
• V
+(MAX)
= 41.4mW
P
OUT(MAX)
= I
OUT
• V
+(MAX)
= 60mW
T
RISE
= θ
JA
• P
TOTAL(MAX)
T
MAX
= T
AMBIENT
+ T
RISE
T
MAX
must be < 150°C
P
TOTAL(MAX)
≈ 96mW and the max die temp
will be 104°C
If this same circuit must run at 125°C, the max die
temp will increase to 150°C. (Note that supply current,
and therefore P
Q
, is proportional to temperature. Refer to
Typical Performance Characteristics section.) In this con-
dition, the maximum output current should be reduced to
avoid device damage. Note that the MSOP package has a
larger θ
JA
than the S5, so additional care must be taken
when operating the LTC6101A/LTC6101HVA at high tem-
peratures and high output currents.
The LTC6101HV can be used at voltages up to 105V. This
additional voltage requires that more power be dissipated
for a given level of current. This will further limit the
allowed output current at high ambient temperatures.
It is important to note that the LTC6101 has been designed
to provide at least 1mA to the output when required, and
can deliver more depending on the conditions. Care must
APPLICATIO S I FOR ATIO
WUUU
LTC6101/LTC6101HV
13
6101fa
APPLICATIO S I FOR ATIO
WUUU
be taken to limit the maximum output current by proper
choice of sense resistor and, if input fault conditions exist,
external clamps.
Output Filtering
The output voltage, V
OUT
, is simply I
OUT
• Z
OUT
. This makes
filtering straightforward. Any circuit may be used which
generates the required Z
OUT
to get the desired filter
response. For example, a capacitor in parallel with R
OUT
will give a low pass response. This will reduce unwanted
noise from the output, and may also be useful as a charge
reservoir to keep the output steady while driving a switch-
ing circuit such as a mux or ADC. This output capacitor in
parallel with an output resistor will create a pole in the
output response at:
fRC
dB OUT OUT
–•• •
31
2
=π
Useful Equations
Input Voltage: V
Voltage Gain: V
V
Current Gain: I
I
Transconductance: I
V
Transimpedance: V
I
SENSE
OUT
SENSE
OUT
SENSE
OUT
SENSE
OUT
SENSE
=
=
=
=
=
IR
R
R
R
R
R
RR
R
SENSE SENSE
OUT
IN
SENSE
IN
IN
SENSE OUT
IN
•
•
1
Input Common Mode Range
The inputs of the LTC6101 can function from 1.5V below
the positive supply to 0.5V above it. Not only does this
Figure 5. V+ Powered Separately from
Load Supply (VBATT)
Figure 6. LTC6101 Supply Current
Monitored with Load
LTC6101
ROUT
VOUT
6101 F05
3
5
4
2
1
RIN
LOAD V+
RSENSE
VBATTERY
–
+
LTC6101
R
OUT
V
OUT
6101 F06
3
5
4
2
1
R
IN
LOAD
V
+
R
SENSE
–
+
allow a wide V
SENSE
range, it also allows the input refer-
ence to be separate from the positive supply (Figure 5).
Note that the difference between V
BATT
and V
+
must be no
more than the common mode range listed in the Electrical
Characteristics table. If the maximum V
SENSE
is less than
500mV, the LTC6101 may monitor its own supply current,
as well as that of the load (Figure 6).
LTC6101/LTC6101HV
14
6101fa
Reverse Supply Protection
Some applications may be tested with reverse-polarity
supplies due to an expectation of this type of fault during
operation. The LTC6101 is not protected internally from
external reversal of supply polarity. To prevent damage
that may occur during this condition, a Schottky diode
should be added in series with V
–
(Figure 7). This will limit
the reverse current through the LTC6101. Note that this
diode will limit the low voltage performance of the LTC6101
by effectively reducing the supply voltage to the part by V
D
.
In addition, if the output of the LTC6101 is wired to a device
that will effectively short it to high voltage (such as
through an ESD protection clamp) during a reverse supply
condition, the LTC6101’s output should be connected
through a resistor or Schottky diode (Figure 8).
Response Time
The LTC6101 is designed to exhibit fast response to inputs
for the purpose of circuit protection or signal transmis-
sion. This response time will be affected by the external
circuit in two ways, delay and speed.
If the output current is very low and an input transient
occurs, there may be an increased delay before the output
voltage begins changing. This can be improved by in-
creasing the minimum output current, either by increasing
R
SENSE
or decreasing R
IN
. The effect of increased output
current is illustrated in the step response curves in the
Typical Performance Characteristics section of this
datasheet. Note that the curves are labeled with respect to
the initial output currents.
The speed is also affected by the external circuit. In this
case, if the input changes very quickly, the internal ampli-
fier will slew the gate of the internal output FET (Figure 1)
in order to maintain the internal loop. This results in
current flowing through R
IN
and the internal FET. This
current slew rate will be determined by the amplifier and
FET characteristics as well as the input resistor, R
IN
. Using
a smaller R
IN
will allow the output current to increase more
quickly, decreasing the response time at the output. This
will also have the effect of increasing the maximum output
current. Using a larger R
OUT
will decrease the response
time, since V
OUT
= I
OUT
• R
OUT
. Reducing R
IN
and increas-
ing R
OUT
will both have the effect of increasing the voltage
gain of the circuit.
Figure 7. Schottky Prevents Damage During Supply Reversal
Figure 8. Additional Resistor R3 Protects
Output During Supply Reversal
6101 F07
LTC6101
R2
4.99k
D1
R1
100
V
BATT
52
1
34
R
SENSE
L
O
A
D
–+
6101 F08
ADC
LTC6101
R2
4.99k
D1
R1
100 VBATT
R3
1k
52
1
34
RSENSE
L
O
A
D
–+
APPLICATIO S I FOR ATIO
WUUU
LTC6101/LTC6101HV
15
6101fa
TYPICAL APPLICATIO S
U
Bidirectional Current Sense Circuit with Separate Charge/Discharge Output
LTC6101 Monitors Its Own Supply Current High-Side-Input Transimpedance Amplifier
L
O
A
D
CHARGER
–+
–+
+
–
+
–
VOUT D = IDISCHARGE • RSENSE
( )
WHEN IDISCHARGE ≥ 0DISCHARGING: ROUT D
RIN D
VOUT C = ICHARGE • RSENSE
( )
WHEN ICHARGE ≥ 0CHARGING: ROUT C
RIN C
6101 TA02
VBATT
2
4
RIN C
100
1
5
3
LTC6101
RIN D
100
5
1
3
RIN C
100
LTC6101
VOUT D
ROUT D
4.99k
ROUT C
4.99k
VOUT C
2
4
RIN D
100
IDISCHARGE RSENSE ICHARGE
L
O
A
D
–+
6101 TA03
R2
4.99k V
OUT
R1
100
VBATT
52
1
34
RSENSE
LTC6101 +
–
VOUT = 49.9 • RSENSE
(
ILOAD + ISUPPLY
)
ILOAD
ISUPPLY
–+
6101 TA04
RL
VO
4.75k4.75k
VS
LASER MONITOR
PHOTODIODE
CMPZ4697*
(10V)
10k
iPD
52
1
34
LTC6101
VO = IPD • RL
*VZ SETS PHOTODIODE BIAS
VZ + 4 ≤ VS ≤ VZ + 60
LTC6101/LTC6101HV
16
6101fa
TO µP
6101 TA06
LTC2433-1
LTC6101
R
OUT
4.99k
R
IN
100Ω
V
OUT
52
1
34
V
SENSE
I
LOAD
4V TO 60V
1µF
5V
L
O
A
D
–+
–
+
V
OUT
= • V
SENSE
= 49.9V
SENSE
R
OUT
R
IN
ADC FULL-SCALE = 2.5V
21
9
8
7
1063
4
5
V
CC
SCK
REF
+
REF
–
GND
IN
+
IN
–
C
C
F
O
SDD
16-Bit Resolution Unidirectional Output into LTC2433 ADC
TYPICAL APPLICATIO S
U
6101 TA07
L
O
A
D
FAULT
OFF ON
1
1
5
5
3
2
4.99k
V
O
R
S
4
3
4
47k
2
8
6
100Ω
100Ω
1%
10µF
63V
1µF
14V
V
LOGIC
SUB85N06-5
V
O
= 49.9 • R
S
• I
L
FOR R
S
= 5mΩ,
V
O
= 2.5V AT I
L
= 10A (FULL SCALE)
LT1910 LTC6101
I
L
Intelligent High-Side Switch with Current Monitor
LTC6101/LTC6101HV
17
6101fa
TYPICAL APPLICATIO S
U
6101 TA08
LTC6101HV
R
IN
V
–
V
–
25
43
V
SENSE
R
SENSE
I
SENSE
LOAD
+–
–+
V
OUT
= V
LOGIC –
I
SENSE
• • N • R
OUT
R
SENSE
R
IN
N = OPTOISOLATOR CURRENT GAIN
V
S
ANY OPTOISOLATOR
R
OUT
V
OUT
V
LOGIC
6101 TA09
LTC6101
R
IN
100Ω
V
OUT
R
OUT
4.99k
52
1
34
L
O
A
D
–+
V
OUT
= • V
SENSE
= 49.9 V
SENSE
R
OUT
R
IN
M1 AND M2 ARE FQD3P50 TM
M1
M2
62V
CMZ59448
500V
2M
V
SENSE
R
SENSE
I
SENSE
+–
DANGER! Lethal Potentials Present — Use Caution
DANGER!!
HIGH VOLTAGE!!
48V Supply Current Monitor with Isolated Output with 105V Survivability
Simple 500V Current Monitor
LTC6101/LTC6101HV
18
6101fa
U
PACKAGE DESCRIPTIO
MS8 Package
8-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1660)
MSOP (MS8) 0204
0.53 ± 0.152
(.021 ± .006)
SEATING
PLANE
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
0.18
(.007)
0.254
(.010)
1.10
(.043)
MAX
0.22 – 0.38
(.009 – .015)
TYP
0.127 ± 0.076
(.005 ± .003)
0.86
(.034)
REF
0.65
(.0256)
BSC
0° – 6° TYP
DETAIL “A”
DETAIL “A”
GAUGE PLANE
12
34
4.90 ± 0.152
(.193 ± .006)
8765
3.00 ± 0.102
(.118 ± .004)
(NOTE 3)
3.00 ± 0.102
(.118 ± .004)
(NOTE 4)
0.52
(.0205)
REF
5.23
(.206)
MIN
3.20 – 3.45
(.126 – .136)
0.889 ± 0.127
(.035 ± .005)
RECOMMENDED SOLDER PAD LAYOUT
0.42 ± 0.038
(.0165 ± .0015)
TYP
0.65
(.0256)
BSC
LTC6101/LTC6101HV
19
6101fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
1.50 – 1.75
(NOTE 4)
2.80 BSC
0.30 – 0.45 TYP
5 PLCS (NOTE 3)
DATUM ‘A’
0.09 – 0.20
(NOTE 3)
S5 TSOT-23 0302
PIN ONE
2.90 BSC
(NOTE 4)
0.95 BSC
1.90 BSC
0.80 – 0.90
1.00 MAX
0.01 – 0.10
0.20 BSC
0.30 – 0.50 REF
NOTE:
1. DIMENSIONS ARE IN MILLIMETERS
2. DRAWING NOT TO SCALE
3. DIMENSIONS ARE INCLUSIVE OF PLATING
4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR
5. MOLD FLASH SHALL NOT EXCEED 0.254mm
6. JEDEC PACKAGE REFERENCE IS MO-193
3.85 MAX
0.62
MAX
0.95
REF
RECOMMENDED SOLDER PAD LAYOUT
PER IPC CALCULATOR
1.4 MIN
2.62 REF
1.22 REF
S5 Package
5-Lead Plastic TSOT-23
(Reference LTC DWG # 05-08-1635)
U
PACKAGE DESCRIPTIO
LTC6101/LTC6101HV
20
6101fa
PART NUMBER DESCRIPTION COMMENTS
LT1636 Rail-to-Rail Input/Output, Micropower Op Amp V
CM
Extends 44V above V
EE
, 55µA Supply Current,
Shutdown Function
LT1637/LT1638/ Single/Dual/Quad, Rail-to-Rail, Micropower Op Amp V
CM
Extends 44V above V
EE
, 0.4V/µs Slew Rate, >1MHz
LT1639 Bandwidth, <250µA Supply Current per Amplifier
LT1787/LT1787HV Precision, Bidirectional, High Side Current Sense Amplifier 2.7V to 60V Operation, 75µV Offset, 60µA Current Draw
LTC1921 Dual –48V Supply and Fuse Monitor ±200V Transient Protection, Drives Three Optoisolators for Status
LT1990 High Voltage, Gain Selectable Difference Amplifier ±250V Common Mode, Micropower, Pin Selectable Gain = 1, 10
LT1991 Precision, Gain Selectable Difference Amplifier 2.7V to ±18V, Micropower, Pin Selectable Gain = –13 to 14
LTC2050/LTC2051/ Single/Dual/Quad Zero-Drift Op Amp 3µV Offset, 30nV/°C Drift, Input Extends Down to V–
LTC2052
LTC4150 Coulomb Counter/Battery Gas Gauge Indicates Charge Quantity and Polarity
Over-The-Top is a trademark of Linear Technology Corporation.
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com
© LINEAR TECHNOLOGY CORPORATION 2005
LT/TP 0805 500 REV A • PRINTED IN USA
RELATED PARTS
U
TYPICAL APPLICATIO
L
O
A
D
CHARGER
–+
–+
+
–
VOUT = IDISCHARGE • RSENSE
( )
WHEN IDISCHARGE ≥ 0DISCHARGING: ROUT
RIN D
VOUT = ICHARGE • RSENSE
( )
WHEN ICHARGE ≥ 0CHARGING: ROUT
RIN C
6101 TA05
VBATT
2
4
RIN C
1
5
3
LTC6101
RIN D
5
1
3
RIN C
LTC6101
ROUT
VOUT
2
4
RIN D
IDISCHARGE ICHARGE
RSENSE
Bidirectional Current Sense Circuit with Combined Charge/Discharge Output