that incorporates a precision current sense amplifier, an
integrated voltage reference and two comparators. Two
versions of the LT6109 are available. The LT6109-1 has
the comparators connected in opposing polarity and the
LT6109-2 has the comparators connected in the same polar-
ity. In addition, the current sense amplifier and comparator
inputs and outputs are directly accessible. The amplifier
gain and comparator trip points are configured by external
resistors. The open-drain comparator outputs allows for
easy interface to other system components.
The overall propagation delay of the LT6109 is typically
only 1.4µs, allowing for quick reaction to overcurrent
and undercurrent conditions. The 1MHz bandwidth al-
lows the LT6109 to be used for error detection in critical
applications such as motor control. The high threshold
accuracy of the comparators, combined with the ability to
latch both comparators, ensures the LT6109 can capture
high speed events.
The LT6109 is fully specified for operation from –40°C to
125°C, making it suitable for industrial and automotive ap-
plications. The LT6109 is available in a small 10-lead MSOP
.
L,
LT, LTC, LTM, TimerBlox, Linear Technology and the Linear logo are registered trademarks
of Linear Technology Corporation. All other trademarks are the property of their respective
owners.
n
n
n
n
n
n
n
Current Sense Amplifier
– Fast Step Response: 500ns
– Low Offset Voltage: 125µV Maximum
– Low Gain Error: 0.2% Maximum
Internal 400mV Precision Reference
Internal Latching Comparators with Reset
– Fast Response Time: 500ns
– Total Threshold Error: ±1.25% Maximum
– Two Comparator Polarity Options
Wide Supply Range: 2.7V to 60V
Supply Current: 550µA
Low Shutdown Current: 5µA Maximum
Specified for –40°C to 125°C Temperature Range
Available in 10-Lead MSOP Package
APPLICATIONS
n
n
n
n
n
n
n
Overcurrent, Undercurrent and Fault Detection
Current Shunt Measurement
Battery Monitoring
Motor Control
Automotive Monitoring and Control
Remote Sensing
Industrial Control
TYPICAL APPLICATION
Circuit Fault Protection with Latching Load Disconnect and Early Warning Indication
12V
6.2V*
1k
3.3V
100
SENSEHI SENSELO
10k
1.62k
100k
V
+
OUTA
LT6109-2
INC2
2.37k
V
–
INC1
1.6k
610912 TA01a
Response to Overcurrent Event
V
LOAD
10V/DIV
0V
I
LOAD
200mA/DIV
0mA
V
OUTC1
5V/DIV 0V
V
OUTC2
5V/DIV 0V
0.1
IRF9640
0.1µF
V
OUT
6.04k
TO LOAD
1k
2N2700
EN/RST
RESET
100mA WARNING
OUTC2
250mA DISCONNECT
OUTC1
250mA DISCONNECT
100mA WARNING
*CMH25234B
5µs/DIV
610912 TA01b
610912fa
1
LT6109-1/LT6109-2
ABSOLUTE MAXIMUM RATINGS
Total Supply Voltage (V
+
to V
–
) .................................60V
Maximum Voltage
(SENSELO, SENSEHI, OUTA) ............................... V
+
+ 1V
Maximum V
+
– (SENSELO or SENSEHI) ....................33V
Maximum EN/RST Voltage ........................................60V
Maximum Comparator Input Voltage ........................60V
Maximum Comparator Output Voltage......................60V
Input Current (Note 2) ..........................................–10mA
SENSEHI, SENSELO Input Current ....................... ±10mA
Differential SENSEHI or SENSELO Input Current ...±2.5mA
Amplifier Output Short-Circuit Duration (to V
–
) .. Indefinite
Operating Temperature Range (Note 3)
LT6109I................................................–40°C to 85°C
LT6109H ............................................ –40°C to 125°C
Specified Temperature Range (Note 3)
LT6109I................................................–40°C to 85°C
LT6109H ............................................ –40°C to 125°C
Maximum Junction Temperature .......................... 150°C
Storage Temperature Range .................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)................... 300°C
(Note 1)
PIN CONFIGURATION
TOP VIEW
SENSELO
EN/RST
OUTC2
OUTC1
V
–
1
2
3
4
5
10
9
8
7
6
SENSEHI
V
+
OUTA
INC2
INC1
MS PACKAGE
10-LEAD PLASTIC MSOP
θ
JA
= 160°C/W,
θ
JC
= 45°C/W
ORDER INFORMATION
LEAD FREE FINISH
LT6109AIMS-1#PBF
LT6109IMS-1#PBF
LT6109AHMS-1#PBF
LT6109HMS-1#PBF
LT6109AIMS-2#PBF
LT6109IMS-2#PBF
LT6109AHMS-2#PBF
LT6109HMS-2#PBF
TAPE AND REEL
LT6109AIMS-1#TRPBF
LT6109IMS-1#TRPBF
LT6109AHMS-1#TRPBF
LT6109HMS-1#TRPBF
LT6109AIMS-2#TRPBF
LT6109IMS-2#TRPBF
LT6109AHMS-2#TRPBF
LT6109HMS-2#TRPBF
PART MARKING*
LTFNJ
LTFNJ
LTFNJ
LTFNJ
LTFWY
LTFWY
LTFWY
LTFWY
PACKAGE DESCRIPTION
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
10-Lead Plastic MSOP
SPECIFIED TEMPERATURE RANGE
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
–40°C to 85°C
–40°C to 85°C
–40°C to 125°C
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to:
http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to:
http://www.linear.com/tapeandreel/
610912fa
2
LT6109-1/LT6109-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
+
I
S
PARAMETER
Supply Voltage Range
Supply Current (Note 4)
V
+
= 2.7V, R
IN
= 1k, V
SENSE
= 5mV
V
+
= 60V, R
IN
= 1k, V
SENSE
= 5mV
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 12V, V
PULLUP
= V
+
, V
EN/RST
= 2.7V, R
IN
= 100Ω,
R
OUT
= R1 + R2 + R3 = 10k, gain = 100, R
C
= 25.5k, C
L
= C
LC
= 2pF unless otherwise noted. (See Figure 3)
,
CONDITIONS
l
MIN
2.7
TYP
475
600
3
MAX
60
700
1000
5
7
11
13
UNITS
V
µA
µA
µA
µA
µA
µA
µA
nA
V
Supply Current in Shutdown
V
+
= 2.7V, V
EN/RST
= 0V, R
IN
= 1k, V
SENSE
= 0.5V
l
V
+
= 60V, V
EN/RST
= 0V, R
IN
= 1k, V
SENSE
= 0.5V
l
7
–200
l
l
EN/RST Pin Current
V
IH
V
IL
V
OS
EN/RST Pin Input High
EN/RST Pin Input Low
Input Offset Voltage
V
EN/RST
= 0V, V
+
= 60V
V
+
= 2.7V to 60V
V
+
= 2.7V to 60V
V
SENSE
= 5mV, LT6109A
V
SENSE
= 5mV, LT6109
V
SENSE
= 5mV, LT6109A
V
SENSE
= 5mV, LT6109
V
SENSE
= 5mV
V
+
= 2.7V to 60V
l
1.9
0.8
–125
–350
–250
–450
±0.8
60
±5
300
350
125
350
250
450
V
µV
µV
µV
µV
µV/°C
nA
nA
nA
mA
dB
dB
dB
dB
dB
mV
Current Sense Amplifier
l
l
l
∆V
OS
/∆T
I
B
I
OS
I
OUTA
PSRR
CMRR
Input Offset Voltage Drift
Input Bias Current
(SENSELO, SENSEHI)
Input Offset Current
Output Current (Note 5)
Power Supply Rejection Ratio
(Note 6)
Common Mode Rejection Ratio
V
+
= 2.7V to 60V
l
1
120
114
110
103
500
–0.08
127
125
125
V
+
= 2.7V to 60V
l
V
+
= 36V, V
SENSE
= 5mV, V
ICM
= 2.7V to 36V
V
+
= 60V, V
SENSE
= 5mV, V
ICM
= 27V to 60V
l
V
SENSE(MAX)
Full-Scale Input Sense Voltage
(Note 5)
Gain Error (Note 7)
SENSELO Voltage (Note 8)
Output Swing High (V
+
to V
OUTA
)
BW
t
r
t
SETTLE
Signal Bandwidth
Input Step Response (to 50% of
Final Output Voltage)
Settling Time to 1%
R
IN
= 500Ω
V
+
= 2.7V to 12V
V
+
= 12V to 60V, V
SENSE
= 5mV to 100mV
V
+
= 2.7V, V
SENSE
= 100mV, R
OUT
= 2k
V
+
= 60V, V
SENSE
= 100mV
V
+
= 2.7V, V
SENSE
= 27mV
V
+
= 12V, V
SENSE
= 120mV
I
OUT
= 1mA
I
OUT
= 100µA
V
+
= 2.7V, V
SENSE
= 24mV Step, Output Rising Edge
V
+
= 12V to 60V, V
SENSE
= 100mV Step, Output Rising Edge
V
SENSE
= 10mV to 100mV, R
OUT
= 2k
l
l
l
l
l
l
–0.2
2.5
27
0
%
%
V
V
0.2
0.5
1
140
500
500
2
V
V
MHz
kHz
ns
ns
µs
610912fa
3
LT6109-1/LT6109-2
ELECTRICAL CHARACTERISTICS
SYMBOL
V
TH(R)
(Note 9)
V
TH(F)
(Note 9)
V
HYS
V
OL
PARAMETER
Rising Input Threshold Voltage
(LT6109-1 Comparator 1
LT6109-2 Both Comparators)
Falling Input Threshold Voltage
(LT6109-1 Comparator 2)
V
HYS
= V
TH(R)
– V
TH(F)
Comparator Input Bias Current
Output Low Voltage
High to Low Propagation Delay
Output Fall Time
t
RESET
t
RPW
Reset Time
Valid
RST
Pulse Width
l
The
l
denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
+
= 12V, V
PULLUP
= V
+
, V
EN/RST
= 2.7V, R
IN
= 100Ω,
R
OUT
= R1 + R2 + R3 = 10k, gain = 100, R
C
= 25.5k, C
L
= C
LC
= 2pF unless otherwise noted. (See Figure 3)
,
CONDITIONS
V
+
= 2.7V to 60V, LT6109A
V
+
= 2.7V to 60V, LT6109
V
+
= 2.7V to 60V, LT6109A
V
+
= 2.7V to 60V, LT6109
V
+
= 2.7V to 60V
V
INC1,2
= 0V, V
+
= 60V
I
OUTC1,C2
= 500µA, V
+
= 2.7V
l
l
l
l
l
l
MIN
395
392
395
392
3
–50
TYP
400
400
400
400
10
60
3
0.5
0.08
0.5
MAX
405
408
405
408
15
150
220
UNITS
mV
mV
mV
mV
mV
nA
mV
mV
µs
µs
µs
µs
Reference and Comparator
5mV Overdrive
100mV Overdrive
2
15
µs
Note 1:
Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2:
Input and output pins have ESD diodes connected to ground. The
SENSEHI and SENSELO pins have additional current handling capability
specified as SENSEHI, SENSELO input current.
Note 3:
The LT6109I is guaranteed to meet specified performance from
–40°C to 85°C. LT6109H is guaranteed to meet specified performance
from –40°C to 125°C.
Note 4:
Supply current is specified with the comparator outputs high.
When the comparator outputs go low the supply current will increase by
75µA typically per comparator.
Note 5:
The full-scale input sense voltage and the maximum output
current must be considered to achieve the specified performance.
Note 6:
Supply voltage and input common mode voltage are varied while
amplifier input offset voltage is monitored.
Note 7:
Specified gain error does not include the effects of external
resistors R
IN
and R
OUT
. Although gain error is only guaranteed between
12V and 60V, similar performance is expected for V
+
< 12V, as well.
Note 8:
Refer to SENSELO, SENSEHI Range in the Applications
Information section for more information.
Note 9:
The input threshold voltage which causes the output voltage of the
comparator to transition from high to low is specified. The input voltage
which causes the comparator output to transition from low to high is
the magnitude of the difference between the specified threshold and the
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