LT1787_15 [Linear]

Precision, High Side Current Sense Amplifiers;
LT1787_15
型号: LT1787_15
厂家: Linear    Linear
描述:

Precision, High Side Current Sense Amplifiers

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LT1787/LT1787HV  
Precision, High Side  
Current Sense Amplifiers  
U
DESCRIPTIO  
FEATURES  
The LT®1787 is a complete micropower precision high  
side current sense amplifier. The LT1787 monitors bidi-  
rectional currents via the voltage across an external sense  
resistor.Acurrentorvoltageoutputindicatesthedirection  
and magnitude of the sense current. The LT1787 delivers  
greater than a 12-bit dynamic range with ultralow 40µV  
input offset voltage compared to a typical 250mV full-  
scale input voltage. A fixed gain of 8 is set by onboard  
precision resistors. Input signal filtering is easily imple-  
mented with a capacitor between the FILand FIL+ pins.  
The LT1787HV operates from 2.5V to 60V total supply  
voltage and the LT1787 operates from 2.5V to 36V total  
supply voltage. Both versions have a PSRR in excess of  
120dB. The LT1787/LT1787HV draw only 60µA and are  
available in 8-lead SO and MSOP packages.  
Input Offset Voltage: 75  
µV (Max)  
60V Supply Operation (LT1787HV)  
12-Bit Dynamic Range  
Operating Current: 60µA  
User-Selectable External Sense Resistor  
Bidirectional High Side Current Sensing  
Unidirectional or Bidirectional Output  
Input Noise Filtering  
–40°C to 125°C Operating Temperature Range  
Available in 8-Lead SO and MSOP Packages  
U
APPLICATIO S  
Battery Monitoring  
Power Monitoring  
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.  
All other trademarks are the property of their respective owners.  
Portable Phones  
Cellular Phones  
Portable Test/Measurement Systems  
Battery-Operated Systems  
U
TYPICAL APPLICATIO  
12-Bit Dynamic Resolution Unidirectional Output into LTC®1286 ADC  
Input Offset Voltage vs Supply Voltage  
50  
40  
30  
20  
R
SENSE  
0.0016  
I = 100A  
TO  
LOAD  
2.5V TO 60V  
1
8
+
+
FIL  
FIL  
LT1787HV  
V
V
S
2
3
S
7
6
R1  
15k  
10  
C1  
5V  
1µF  
V
R
BIAS  
0
–10  
–20  
DNC  
OUT  
20k  
V
V
CC  
REF  
4
5
CS  
CLK  
V
+IN  
EE  
LTC1286  
TO µP  
V
OUT  
–30  
–40  
–50  
–IN  
D
OUT  
GND  
C2  
0.1µF  
1787 TA01  
LT1634-1.25  
V
= V  
+ (8 • I  
• R  
)
SENSE  
OUT  
BIAS  
LOAD  
0
10  
30  
40  
50  
60  
20  
TOTAL SUPPLY VOLTAGE (V)  
1787 TA01b  
1787fc  
1
LT1787/LT1787HV  
W W  
U W  
ABSOLUTE MAXIMUM RATINGS  
(Notes 1, 2)  
Differential Sense Voltage...................................... ±10V  
Total Supply Voltage (LT1787) ................................ 40V  
Total Supply Voltage (LT1787HV) ........................... 65V  
Output Voltage..................... (VEE – 0.3V) to (VEE + 35V)  
Output Bias Voltage ............. (VEE – 0.3V) to (VEE + 35V)  
Operating Temperature Range (Note 3)  
Specified Temperature Range (Note 4)  
LT1787C............................................. 40°C to 85°C  
LT1787I .............................................. 40°C to 85°C  
LT1787H .......................................... 40°C to 125°C  
Storage Temperature Range ..................–65°C to 150°C  
Lead Temperature (Soldering, 10 sec).................. 300°C  
LT1787C............................................. 40°C to 85°C  
LT1787I .............................................. 40°C to 85°C  
LT1787H .......................................... 40°C to 125°C  
U
W U  
PACKAGE/ORDER INFORMATION  
TOP VIEW  
TOP VIEW  
+
FIL  
1
2
3
4
8
7
6
5
FIL  
+
+
FIL  
1
2
3
4
8
7
6
5
FIL  
+
V
S
V
V
V
S
V
V
V
V
S
S
DNC*  
EE  
BIAS  
OUT  
DNC*  
BIAS  
OUT  
V
V
EE  
MS8 PACKAGE  
8-LEAD PLASTIC MSOP  
S8 PACKAGE  
* DO NOT CONNECT  
JMAX = 150°C, θJA = 250°C/ W  
8-LEAD PLASTIC SO  
T
* DO NOT CONNECT  
TJMAX = 150°C, θJA = 190°C/ W  
MS8 PART MARKING  
S8 PART MARKING  
ORDER PART NUMBER  
ORDER PART NUMBER  
LT1787CMS8  
LT1787IMS8  
LT1787HVCMS8  
LT1787HVIMS8  
LTGM  
LTGN  
LTKJ  
LTKK  
LT1787CS8  
1787  
LT1787IS8  
1787I  
LT1787HS8  
LT1787HVCS8  
LT1787HVIS8  
LT1787HVHS8  
1787H  
1787HV  
787HVI  
787HVH  
Order Options Tape and Reel: Add #TR  
Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF  
Lead Free Part Marking: http://www.linear.com/leadfree/  
Consult LTC Marketing for parts specified with wider operating temperature ranges.  
(Note 5)  
ELECTRICAL CHARACTERISTICS  
denotes the specifications which apply over the temperature range 0°C T 70°C, otherwise specifications are at T = 25°C.  
A A  
The  
Total supply = (V – V ) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified.  
S
EE  
SYMBOL PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
+
V
, V  
Sense Amplifier Supply Voltage Single Supply Operation (LT1787)  
Single Supply Operation (LT1787HV)  
2.5  
2.5  
36  
60  
V
V
S
S
+
V
V
Input Sense Voltage Full Scale  
Input Offset Voltage (S8)  
V
= V – V , V = 10V, V  
= 5V, A = 8 ±10%  
500  
mV  
SENSE  
OS  
SENSE  
S
S
S
BIAS  
V
I
= 0, V Supply = 5V  
75  
135  
± 40  
75  
135  
µV  
µV  
µV  
µV  
µV  
µV  
OUT  
S
0°C T 70°C  
A
I
= 0 (LT1787)  
A
100  
160  
100  
160  
OUT  
0°C T 70°C  
I
= 0 (LT1787HV)  
A
100  
160  
100  
160  
OUT  
0°C T 70°C  
1787fc  
2
LT1787/LT1787HV  
(Note 5)  
ELECTRICAL CHARACTERISTICS  
The  
denotes the specifications which apply over the temperature range 0°C T 70°C, otherwise specifications are at T = 25°C.  
Total supply = (V – V ) = 2.5V to 36V (LT1787C), 2.5V to 60V (LT1787HVC) unless otherwise specified.  
A
A
S
EE  
SYMBOL PARAMETER  
CONDITIONS  
= 0, V Supply = 5V  
MIN  
TYP  
MAX  
UNITS  
Input Offset Voltage (MS8)  
I
125  
230  
± 40  
125  
230  
µV  
µV  
µV  
µV  
OUT  
S
0°C T 70°C  
A
I
= 0 (LT1787)  
150  
250  
150  
250  
OUT  
0°C T 70°C  
A
I
= 0 (LT1787HV)  
A
150  
250  
150  
250  
µV  
µV  
µV/°C  
OUT  
0°C T 70°C  
V Supply = 5V (Note 6)  
V
TC  
Temperature Coefficient of V  
0.5  
4
2
OS  
OS  
S
I
No-Load Output Current Error  
V
V
= 0V  
nA  
OUT(O)  
SENSE  
V
No-Load Output Voltage Error  
(S8)  
= 0V, V Supply = 5V  
–600  
1080  
600  
1080  
µV  
µV  
µV  
µV  
OUT(O)  
SENSE  
S
0°C T 70°C  
V
0°C T 70°C  
A
No-Load Output Voltage Error  
(MS8)  
= 0V, V Supply = 5V  
1000  
1840  
1000  
1840  
SENSE  
S
A
g
Tranconductance, I /V  
±V = 10mV, 50mV, 100mV, 150mV, 250mV,  
SENSE  
400  
µA/V  
m
OUT SENSE  
V Supply = Total Supply + |V  
|
S
SENSE  
A
Gain, V / V  
±V  
±V  
= 100mV, V Supply = 5V  
7.76  
–3  
8
1
8.24  
3
V/V  
%
V
OUT SENSE  
SENSE  
SENSE  
S
Output Voltage Gain Error  
= 100mV, V Supply = 5V  
S
V PSRR V Supply Rejection Ratio  
V
V
= 0V, V Supply = 2.5V to 36V (LT1787)  
120  
120  
135  
135  
dB  
dB  
S
S
SENSE  
SENSE  
S
= 0V, V Supply = 2.5V to 60V (LT1787HV)  
S
V
PSRR Negative Supply Rejection Ratio  
V
V
= 0V, V Supply = 15V, V  
= 1V to 15V (LT1787)  
= 0V,  
= 0V,  
100  
130  
dB  
EE  
SENSE  
S
BIAS  
BIAS  
EE  
V
V
= 0V, V Supply = 40V, V  
S
= 1V to 15V (LT1787HV)  
100  
130  
dB  
SENSE  
EE  
V  
Change in Input Offset Voltage  
with Change in V Voltage  
V
V
= 0V, V Supply = 36V, V  
= 0.5V to 25V (LT1787)  
= 0.5V to 25V (LT1787HV)  
100  
100  
130  
130  
dB  
dB  
OS  
SENSE  
SENSE  
S
BIAS  
BIAS  
V  
= 0V, V Supply = 60V, V  
BIAS  
BIAS  
S
+
I
I
I
I
Positive Input Sense Current  
Negative Input Sense Current  
Negative Supply Current  
Output Current  
V
V
V
V
V
V
= 0V  
= 0V  
= 0V  
10  
50  
20  
µA  
µA  
µA  
µA  
V
S (O)  
SENSE  
SENSE  
SENSE  
SENSE  
100  
120  
S (O)  
60  
EE(O)  
OUT  
= ±128mV  
± 50  
±1.024  
BIAS  
+
V
Output Voltage  
= ±128mV, V 3.3V  
V
OUT  
SENSE  
+
S
Ripple Rejection  
= V = 20V, V Supply = 1V, f = 1kHz  
80  
88  
dB  
S
S
S
V
Minimum Output Voltage  
V
V
= 0V, V  
= 0V  
30  
10  
45  
49  
mV  
mV  
OMIN  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
= 0V  
= 0V  
S
S
BIAS  
BIAS  
V
V
= 0V, V  
= 0V  
30  
10  
mV  
mV  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
S
S
Unipolar Output  
Saturation Voltage  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
50  
55  
60  
65  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
54  
59  
64  
69  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
+
V
Maximum Output Voltage  
Input Gain-Setting Resistor  
Output Resistor  
V
– 0.75  
S
V
kΩ  
kΩ  
OMAX  
R
R
R
Pin 1 to Pin 2, Pin 7 to Pin 8  
Pin 5 to Pin 6  
1.25  
20  
G1A, G2A  
OUT  
1787fc  
3
LT1787/LT1787HV  
ELECTRICAL CHARACTERISTICS  
The  
denotes the specifications which apply over the temperature range –40°C T 85°C, otherwise specifications are at  
A
T = 25°C. Total supply = (V – V ) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5)  
A
S
EE  
SYMBOL PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
+
V
, V  
Sense Amplifier Supply Voltage Single Supply Operation (LT1787)  
Single Supply Operation (LT1787HV)  
2.5  
2.5  
36  
60  
V
V
S
S
+
V
V
Input Sense Voltage Full Scale  
Input Offset Voltage (S8)  
V
= V – V , V = 10V, V  
= 5V, A = 8 ±10%  
500  
mV  
SENSE  
OS  
SENSE  
S
S
S
BIAS  
V
I
= 0, V Supply = 5V  
40°C T 85°C  
75  
200  
± 40  
75  
200  
µV  
µV  
OUT  
S
A
I
= 0 (LT1787)  
40°C T 85°C  
100  
225  
100  
225  
µV  
µV  
OUT  
A
I
= 0 (LT1787HV)  
40°C T 85°C  
100  
225  
100  
225  
µV  
µV  
OUT  
A
Input Offset Voltage (MS8)  
I
= 0, V Supply = 5V  
40°C T 85°C  
125  
250  
± 40  
125  
250  
µV  
µV  
OUT  
S
A
I
= 0 (LT1787)  
40°C T 85°C  
150  
280  
150  
280  
µV  
µV  
OUT  
A
I
= 0 (LT1787HV)  
150  
280  
150  
280  
µV  
µV  
OUT  
40°C T 85°C  
A
V
TC  
Temperature Coefficient of V  
V Supply = 5V (Note 6)  
0.5  
4
2
µV/°C  
OS  
OS  
S
I
No-Load Output Current Error  
V
V
= 0V  
nA  
OUT(O)  
SENSE  
V
No-Load Output Voltage Error  
(S8)  
= 0V, V Supply = 5V  
–600  
1600  
600  
1600  
µV  
µV  
OUT(O)  
SENSE  
S
40°C T 85°C  
A
No-Load Output Voltage Error  
(MS8)  
V
= 0V, V Supply = 5V  
1000  
2000  
1000  
2000  
µV  
µV  
SENSE  
S
40°C T 85°C  
A
g
Tranconductance, I /V  
±V = 10mV, 50mV, 100mV, 150mV, 250mV,  
SENSE  
400  
µA/V  
m
OUT SENSE  
V Supply = Total Supply + |V  
|
S
SENSE  
A
Gain, V / V  
±V  
±V  
= 100mV, V Supply = 5V  
7.76  
–3  
8
1
8.24  
3
V/V  
%
V
OUT SENSE  
SENSE  
SENSE  
S
Output Voltage Gain Error  
= 100mV, V Supply = 5V  
S
V PSRR V Supply Rejection Ratio  
V
V
= 0V, V Supply = 2.5V to 36V (LT1787)  
120  
120  
135  
135  
dB  
dB  
S
S
SENSE  
SENSE  
S
= 0V, V Supply = 2.5V to 60V (LT1787HV)  
S
V
PSRR Negative Supply Rejection Ratio  
V
V
= 0V, V Supply = 15V, V  
= 1V to 15V (LT1787)  
= 0V,  
100  
130  
dB  
EE  
SENSE  
S
BIAS  
BIAS  
EE  
V
V
= 0V, V Supply = 40V, V  
S
= 1V to 15V (LT1787HV)  
= 0V,  
100  
130  
dB  
SENSE  
EE  
V  
BIAS  
Change in Input Offset Voltage  
with Change in V Voltage  
V
V
= 0V, V Supply = 36V, V  
= 0.5V to 25V (LT1787)  
= 0.5V to 25V (LT1787HV)  
100  
100  
130  
130  
dB  
dB  
OS  
SENSE  
SENSE  
S
BIAS  
BIAS  
V  
= 0V, V Supply = 60V, V  
BIAS  
S
+
I
I
I
I
Positive Input Sense Current  
Negative Input Sense Current  
Negative Supply Current  
Output Current  
V
V
V
V
V
V
= 0V  
= 0V  
= 0V  
10  
50  
20  
µA  
µA  
µA  
µA  
V
S (O)  
SENSE  
SENSE  
SENSE  
SENSE  
100  
120  
S (O)  
60  
EE(O)  
OUT  
= ±128mV  
± 50  
+
V
Output Voltage  
= ±128mV, V 3.3V  
V
±1.024  
BIAS  
OUT  
SENSE  
+
S
Ripple Rejection  
= V = 20V, V Supply = 1V, f = 1kHz  
80  
88  
dB  
S
S
S
V
Minimum Output Voltage  
V
V
= 0V, V  
= 0V  
30  
10  
45  
51  
mV  
mV  
OMIN  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
= 0V  
= 0V  
S
S
BIAS  
BIAS  
V
V
= 0V, V  
= 0V  
30  
10  
mV  
mV  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
S
S
1787fc  
4
LT1787/LT1787HV  
ELECTRICAL CHARACTERISTICS  
denotes the specifications which apply over the temperature range –40°C T 85°C, otherwise specifications are at  
A
The  
A
T = 25°C. Total supply = (V – V ) = 2.5V to 36V (LT1787I), 2.5V to 60V (LT1787HVI) unless otherwise specified. (Note 5)  
S
EE  
SYMBOL PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX  
UNITS  
Unipolar Output  
Saturation Voltage  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
50  
55  
60  
65  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
56  
61  
66  
71  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
+
V
Maximum Output Voltage  
V
– 0.75  
S
V
kΩ  
kΩ  
OMAX  
R
R
R
Input Gain-Setting Resistor  
Output Resistor  
Pin 1 to Pin 2, Pin 7 to Pin 8  
Pin 5 to Pin 6  
1.25  
20  
G1A, G2A  
OUT  
The  
A
denotes the specifications which apply over the temperature range –40°C T 125°C, otherwise specifications are at  
A
T = 25°C. Total supply = (V – V ) = 2.5V to 36V (LT1787H), 2.5V to 60V (LT1787HVH) unless otherwise specified. (Note 5)  
S
EE  
+
V
, V  
Sense Amplifier Supply Voltage Single Supply Operation (LT1787H)  
Single Supply Operation (LT1787HVH)  
2.5  
2.5  
36  
60  
V
V
S
S
+
V
V
Input Sense Voltage Full Scale  
Input Offset Voltage  
V
= V – V , V = 10V, V  
= 5V, A = 8 ±10%  
500  
mV  
SENSE  
OS  
SENSE  
S
S
S
BIAS  
V
I
= 0, V Supply = 5V  
40°C T 125°C  
75  
400  
± 40  
75  
400  
µV  
µV  
OUT  
S
A
I
= 0 (LT1787H)  
40°C T 125°C  
100  
550  
100  
550  
µV  
µV  
OUT  
A
I
= 0 (LT1787HVH)  
100  
550  
100  
550  
µV  
µV  
OUT  
40°C T 125°C  
A
V
TC  
Temperature Coefficient of V  
V Supply = 5V (Note 6)  
0.5  
4
4
µV/°C  
OS  
OS  
S
I
No-Load Output Current Error  
No-Load Output Voltage Error  
V
V
= 0V  
nA  
OUT(O)  
SENSE  
V
= 0V, V Supply = 5V  
–600  
3200  
600  
3200  
µV  
µV  
OUT(O)  
SENSE  
S
40°C T 125°C  
A
g
Tranconductance, I /V  
±V  
S
= 10mV, 50mV, 100mV, 150mV, 250mV,  
SENSE  
400  
µA/V  
m
OUT SENSE  
V Supply = Total Supply + |V  
|
SENSE  
A
Gain, V / V  
±V  
±V  
= 100mV, V Supply = 5V  
7.76  
–3  
8
1
8.24  
3
V/V  
%
V
OUT SENSE  
SENSE  
SENSE  
S
Output Voltage Gain Error  
= 100mV, V Supply = 5V  
S
V PSRR V Supply Rejection Ratio  
V
V
= 0V, V Supply = 2.5V to 36V (LT1787H)  
100  
100  
130  
130  
dB  
dB  
S
S
SENSE  
SENSE  
S
= 0V, V Supply = 2.5V to 60V (LT1787HVH)  
S
V
PSRR Negative Supply Rejection Ratio  
V
V
= 0V, V Supply = 15V, V  
= 1V to 15V (LT1787H)  
= 0V,  
100  
130  
dB  
EE  
SENSE  
S
BIAS  
EE  
V
V
= 0V, V Supply = 40V, V  
S
= 1V to 15V (LT1787HVH)  
= 0V,  
100  
130  
dB  
SENSE  
BIAS  
EE  
V  
BIAS  
Change in Input Offset Voltage  
with Change in V Voltage  
V
V
= 0V, V Supply = 36V, V  
= 0.5V to 25V (LT1787H)  
= 0.5V to 25V (LT1787HVH)  
100  
100  
130  
130  
dB  
dB  
OS  
SENSE  
SENSE  
S
BIAS  
BIAS  
V  
= 0V, V Supply = 60V, V  
BIAS  
S
+
I
I
I
I
Positive Input Sense Current  
Negative Input Sense Current  
Negative Supply Current  
Output Current  
V
V
V
V
V
V
= 0V  
= 0V  
= 0V  
10  
50  
25  
µA  
µA  
µA  
µA  
V
S (O)  
SENSE  
SENSE  
SENSE  
SENSE  
115  
140  
S (O)  
60  
EE(O)  
OUT  
= ±128mV  
± 50  
+
V
Output Voltage  
= ±128mV, V 3.3V  
V
±1.024  
BIAS  
OUT  
SENSE  
+
S
Ripple Rejection  
= V = 20V, V Supply = 1V, f = 1kHz  
80  
88  
dB  
S
S
S
1787fc  
5
LT1787/LT1787HV  
ELECTRICAL CHARACTERISTICS  
The  
denotes the specifications which apply over the temperature range –40°C T 125°C, otherwise specifications are at  
A
T = 25°C. Total supply = (V – V ) = 2.5V to 36V (LT1787H), 2.5V to 60V (LT1787HVH) unless otherwise specified. (Note 5)  
A
S
EE  
SYMBOL PARAMETER  
CONDITIONS  
MIN  
TYP  
MAX UNITS  
V
Minimum Output Voltage  
V
V
= 0V, V  
= 0V  
30  
10  
45  
mV  
mV  
OMIN  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
= 0V  
= 0V  
S
S
BIAS  
BIAS  
V
V
= 0V, V  
= 0V  
30  
10  
55  
mV  
mV  
SENSE  
SENSE  
BIAS  
+
= V – V = –128mV, V  
S
S
Unipolar Output  
Saturation Voltage  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
50  
55  
60  
65  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
V
V
V
V
= 2mV, V  
= 4mV, V  
= 5mV, V  
= 6mV, V  
= 0V  
= 0V  
= 0V  
= 0V  
32  
38  
43  
49  
60  
65  
70  
75  
mV  
mV  
mV  
mV  
SENSE  
SENSE  
SENSE  
SENSE  
BIAS  
BIAS  
BIAS  
BIAS  
+
V
Maximum Output Voltage  
V
– 0.75  
S
V
kΩ  
kΩ  
OMAX  
R
R
R
Input Gain-Setting Resistor  
Output Resistor  
Pin 1 to Pin 2, Pin 7 to Pin 8  
Pin 5 to Pin 6  
1.25  
20  
G1A, G2A  
OUT  
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: ESD (Electrostatic Discharge) sensitive devices. Extensive use of  
ESD protection devices are used internal to the LT1787/LT1787HV,  
however, high electrostatic discharge can damage or degrade the device.  
Use proper ESD handling precautions.  
guaranteed functional over the operating temperature range of –40°C to  
125°C.  
Note 4: The LT1787C is guaranteed to meet specified performance from  
0°C to 70°C. The LT1787C is designed, characterized and expected to  
meet specified performance from –40°C to 85°C but is not tested or QA  
sampled at these temperatures. The LT1787I is guaranteed to meet  
specified performance from 40°C to 85°C. The LT1787H is guaranteed to  
meet specified performance from –40°C to 125°C.  
Note 3: The LT1787C/LT1787I are guaranteed functional over the  
operating temperature range of –40°C to 85°C. The LT1787H is  
Note 5: Testing done at V  
specified.  
= 1.25V, V = 0V unless otherwise  
BIAS EE  
Note 6: This parameter is not 100% tested.  
W
U
TYPICAL PERFORMANCE CHARACTERISTICS  
No Load Output Voltage  
Input Offset Voltage vs  
No Load Output Current vs  
Supply Voltage  
vs Supply Voltage  
Supply Voltage  
10  
8
50  
40  
400  
+
+
V
V
V
= V  
V
V
V
= V  
T = –40°C  
A
S
S
S
S
= 0V  
= –1.25V  
= 0V  
BIAS  
= –1.25V  
EE  
300  
BIAS  
EE  
6
30  
T
= 85°C  
T
= 85°C  
A
A
200  
T
= 25°C  
= 85°C  
A
4
20  
100  
2
10  
0
0
0
T
= 25°C  
A
A
T
= 25°C  
A
–2  
–4  
–6  
–8  
–10  
–10  
–20  
–30  
–40  
–50  
T
A
–100  
–200  
–300  
–400  
V
V
V
= 1V  
T
= –40°C  
BIAS  
T
= –40°C  
A
= 0V  
EE  
+
= V  
S
S
0
10  
30  
40  
50  
60  
20  
0
10  
30  
40  
50  
60  
50  
20  
0
10  
20  
30  
40  
60  
TOTAL SUPPLY VOLTAGE (V)  
TOTAL SUPPLY VOLTAGE (V)  
TOTAL SUPPLY VOLTAGE (V)  
1787 G03  
1787 G01  
1787 G02  
1787fc  
6
LT1787/LT1787HV  
W
U
TYPICAL PERFORMANCE CHARACTERISTICS  
Input Offset Voltage vs  
Temperature  
Input Offset Voltage vs  
Negative Supply Voltage  
Output Voltage vs Sense Voltage  
(Bidirectional Mode)  
30  
20  
50  
40  
+
+
2.5  
2.0  
1.5  
1.0  
0.5  
V
V
V
= V  
S
V
V
= V = 2.5V  
S
V
V
V
= 5.5V TO 60V  
= 2.5V  
EE  
S
S
S
BIAS  
= 0V  
= 1V  
T
= 85°C  
BIAS  
= –1.25V  
BIAS  
A
30  
= 0V  
EE  
20  
10  
10  
0
0
V
BIAS  
T
= 25°C  
A
–10  
–20  
–30  
–40  
–50  
–0.5  
–1.0  
–1.5  
–2.0  
–2.5  
–10  
–20  
–30  
T
= –40°C  
A
0
–5  
–10  
–15  
–20  
–25  
–30  
–40 –20  
0
20  
40  
60  
80  
85  
–250  
–150  
–50  
50  
+
150  
250  
NEGATIVE SUPPLY VOLTAGE (V)  
TEMPERATURE (°C)  
SENSE VOLTAGE (V – V ) (mV)  
S
S
1787 G04  
1787 G05  
1787 G06  
Output Voltage vs Sense Voltage  
(Unidirectional Mode)  
Gain vs Temperature  
Gain vs Frequency  
8.195  
8.185  
8.175  
8.165  
8.155  
8.145  
8.135  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0
30  
20  
V
= (2.5V + |V  
|)TO 60V  
V
= 10mV  
V
T
BIAS  
= 2.5V TO 60V  
S
SENSE  
SENSE  
S
A
V
= –40°C TO 85°C  
= V  
EE  
+
V
V
> V  
S
S
S
10  
0
–10  
–20  
–30  
–40  
–50  
+
< V  
40  
S
–40 –20  
0
20  
60  
80  
85  
30  
60  
90  
+
150  
0
120  
10M  
0.1k  
1k  
10k 100k  
1M  
100M  
TEMPERATURE (°C)  
FREQUENCY (Hz)  
SENSE VOLTAGE (V – V ) (mV)  
S
S
1787 G08  
1787 G07  
1787 G09  
Negative Input Sense Current vs  
Sense Voltage  
Positive Input Sense Current vs  
Sense Voltage  
Supply Current vs Supply Voltage  
120  
110  
100  
90  
60  
50  
40  
30  
20  
10  
0
75  
70  
65  
60  
55  
50  
45  
40  
V
= (2.5V + |V  
|) TO 60V  
SENSE  
V
= (2.5V + |V  
|) TO 60V  
SENSE  
S
S
T
A
= 85°C  
T
A
= 25°C  
80  
T = 85°C  
A
T
= –40°C  
70  
A
T
T
= 85°C  
= 25°C  
A
60  
A
T
= 25°C  
T
= –40°C  
A
A
50  
T
= –40°C  
A
40  
+
V
= V  
10  
S
S
30  
–128  
0
64 96  
–128  
0
64 96  
–96 –64 –32  
32  
128  
–96 –64 –32  
32  
128  
0
20  
30  
40  
50  
60  
+
+
SENSE VOLTAGE (V – V ) (mV)  
SENSE VOLTAGE (V – V ) (mV)  
TOTAL SUPPLY VOLTAGE (V)  
S
S
S
S
1787 G11  
1787 G17  
1787 G10  
1787fc  
7
LT1787/LT1787HV  
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U
TYPICAL PERFORMANCE CHARACTERISTICS  
Step Response at  
SENSE  
Step Response at  
V = 0V to 128mV  
SENSE  
Step Response at  
= 0V to 128mV  
V
= 0V to 10mV  
V
SENSE  
10mV  
0V  
100mV  
0V  
100mV  
0V  
80mV  
1V  
500mV  
0V  
1V  
500mV  
0V  
0V  
C
OUT  
= 1000pF  
1787 G13  
C
= 0pF  
1787 G12  
OUT  
C
OUT  
= 0pF  
1787 G18  
Step Response at  
= 0V to –128mV  
Step Response at  
= 0V to –128mV  
Step Response at  
V = 128mV to 128mV  
SENSE  
V
V
SENSE  
SENSE  
0V  
100mV  
0V  
100mV  
0V  
100mV  
–100mV  
0V  
500mV  
1V  
1V  
0V  
0V  
–500mV  
–1V  
–1V  
C
= 1000pF  
1787 G14  
C = 0  
OUT  
1787 G20  
C
= 0  
1787 G19  
OUT  
OUT  
Step Response at  
= 128mV to –128mV  
V
Error vs Supply Ripple  
OUT  
Output Voltage vs Sense Voltage  
V
Voltage (V  
= ±128mV)  
SENSE  
SENSE  
16  
1000  
900  
800  
700  
600  
500  
400  
300  
200  
100  
0
V
V
V
= 18V  
14  
12  
10  
8
S
100mV  
= 0V  
BIAS  
EE  
–100mV  
= –18V  
1V  
0V  
6
4
0.5%  
5%  
1%  
2
–1V  
0
2%  
–2  
–4  
–6  
–8  
V
ERROR  
LESS THAN 0.1%  
OUT  
C
OUT  
= 2200pF  
1787 G15  
0.4  
SENSE VOLTAGE (V – V ) (V)  
–0.8 –0.4  
0
0.8 1.2 1.6 2.0  
100  
1k  
10k  
100k  
1M  
+
FREQUENCY (Hz)  
S
S
1787 G16  
1787 G21  
1787fc  
8
LT1787/LT1787HV  
U
U
U
PIN FUNCTIONS  
FIL, FIL+ (Pins 1, 8): Negative and Positive Filter Termi-  
nals. Differential mode noise can be filtered by connecting  
a capacitor across FILand FIL+. Pole frequency  
where:  
VOUT > VBIAS for VS+ > VS–  
VOUT < VBIAS for VS+ < VS  
f3dB = 1/(2πRC), R = 1.25k.  
VOUT(O) is the no load output voltage at VSENSE = 0V.  
VS (Pin 2): Negative Input Sense Terminal. Negative  
sense voltage will result in an output sinking current  
proportional to the sense current. VSis connected to an  
internal gain-setting resistor RG1A and supplies bias cur-  
rent to the internal amplifier.  
VBIAS (Pin 6): Output Bias Pin. For single supply, bidirec-  
tional current sensing operation, VBIAS is connected to an  
external bias voltage, so that at VSENSE = 0V, VOUT  
=
VOUT(O) + VBIAS. For dual supply, bidirectional current  
sensing operation, VBIAS is connected to ground. Thus,  
DNC(Pin3):DoNotConnect.Connectedinternally.Donot  
connect external circuitry to this pin.  
V
OUT = VOUT(O) at VSENSE = 0V.  
VS+ (Pin 7): Positive Input Sense Terminal. Positive sense  
voltage will result in an output sourcing current propor-  
tional to the sense current. VS+ is connected to an internal  
VEE (Pin 4): Negative Supply or Ground for Single Supply  
Operation.  
+
gain-settingresistorRG2A. ConnectingasupplytoVS and  
VOUT (Pin 5): Voltage Output or Current Output propor-  
tional to the magnitude of the sense current flowing  
through RSENSE. For bidirectional current sensing opera-  
a load to VS will allow the LT1787 to measure its own  
supply current.  
tion, VOUT = AV • VSENSE + VOUT(O) + VBIAS  
,
W
BLOCK DIAGRAM  
R
SENSE  
I
SENSE  
+
V
S
V
S
R
G1A  
1.25k  
R
G2A  
1.25k  
+
FIL  
FIL  
R
G1B  
1.25k  
R
G2B  
1.25k  
+
A1  
I
OUT  
V
BIAS  
R
OUT  
Q1  
Q2  
20k  
V
OUT  
V
EE  
CURRENT MIRROR  
1787 F 01  
Figure 1. LT1787 Functional Diagram  
1787fc  
9
LT1787/LT1787HV  
U
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APPLICATIONS INFORMATION  
The LT1787 high side current sense amplifier (Figure 1)  
provides accurate bidirectional monitoring of current  
through a user-selected sense resistor. The sense voltage  
is amplified by a fixed gain of 8 and level shifted from the  
positive power supply to the ground referenced outputs.  
The output signal may be used in a variety of ways to  
interface with subsequent signal processing circuitry.  
Input and output filtering are easily implemented to elimi-  
nate aliasing errors.  
Kelvin connection of the LT1787’s VS+ and VSinputs to  
the sense resistor should be used in all but the lowest  
power applications. Solder connections and PC board  
interconnectresistance(approximately0.5mpersquare)  
can be a large error in high current systems. A 5-Amp  
application might choose a 20msense resistor to give a  
100mV full-scale input to the LT1787. Input offset voltage  
will limit resolution to 2mA. Neglecting contact resistance  
at solder joints, even one square of PC board copper at  
each resistor end will cause an error of 5%. This error will  
grow proportionately higher as monitored current levels  
rise to tens or hundreds of amperes.  
Theory of Operation  
+
Inputs VS and VS apply the sense voltage to matched  
resistors RG1 and RG2. The opposite ends of resistors RG1  
and RG2 are forced to be at equal potentials by the voltage  
gainofamplifierA1. ThecurrentsthroughRG1 andRG2 are  
forced to flow through transistors Q1 and Q2 and are  
summed at node VOUT by the 1:1 current mirror. The net  
current from RG1 and RG2 flowing through resistor ROUT  
givesavoltagegainofeight. Positivesensevoltagesresult  
Input Noise Filtering  
The LT1787 provides input signal filtering pins FIL+ and  
FILthat are internally connected to the midpoint taps of  
resistors RG1 and RG2. These pins may be used to filter the  
input signal entering the LT1787’s internal amplifier, and  
should be used when fast current ripple or transients may  
flow through the sense resistor. High frequency signals  
above the 300kHz bandwidth of the LT1787’s internal  
amplifierwillcauseerrors.Acapacitorconnectedbetween  
FIL+ and FILcreates a single pole low pass filter with  
corner frequency:  
in VOUT being positive with respect to pin VBIAS  
.
Pins VEE, VBIAS and VOUT may be connected in a variety of  
ways to interface with subsequent circuitry. Split supply  
and single supply output configurations are shown in the  
following sections.  
Supply current for amplifier A1 is drawn from the VSpin.  
The user may choose to include this current in the moni-  
tored current through RSENSE by careful choice of connec-  
tion polarity.  
f–3dB = 1/(2πRC)  
where R = 1.25k. A 0.01µF capacitor creates a pole at  
12.7kHz, a good choice for many applications.  
CommonmodefilteringfromtheFIL+ andFILpinsshould  
not be attempted, as mismatch in the capacitors from FIL+  
and FILwill create AC common mode errors. Common  
mode filtering must be done at the power supply output.  
Selection of External Current Sense Resistor  
External RSENSE resistor selection is a delicate trade-off  
between power dissipation in the resistor and current  
measurement accuracy. The LT1787 makes this decision  
less difficult than with competitors’ products. The maxi-  
mum sense voltage may be as large as ±500mV to get  
maximum resolution, however, high current applications  
will not want to suffer this much power dissipation in the  
sense resistor. The LT1787’s input offset voltage of 40µV  
gives high resolution for low sense voltages. This wide  
operating dynamic range gives the user wide latitude in  
tailoringtherangeandresolutionofhissupplymonitoring  
function.  
Output Signal Range  
The LT1787’s output signal is developed by summing the  
net currents through RG1 and RG2 into output resistor  
ROUT. The pins VOUT and VBIAS may be connected in  
numerous configurations to interface with following cir-  
cuitry in either single supply or split supply applications.  
Care must be used in connecting the output pins to  
preserve signal accuracy. Limitations on the signal swing  
at VOUT are imposed by the negative supply, VEE, and the  
+
input voltage VS . In the negative direction, internal circuit  
saturation with loss of accuracy occurs for VOUT < 70mV  
1787fc  
10  
LT1787/LT1787HV  
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APPLICATIONS INFORMATION  
1.5  
1.0  
with absolute minimum swing at 30mV above VEE. VOUT  
may swing positive to within 0.75V of VS+ or a maximum  
of 35V, a limit set by internal junction breakdown. Within  
thesecontraints, anamplified, levelshiftedrepresentation  
V
= 3.3V TO 60V  
= 40°C TO 85°C  
S
A
T
0.5  
of the RSENSE voltage is developed across ROUT  
.
0
Split Supply Bipolar Output Swing  
–0.5  
–1.0  
–1.5  
Figure2showstheLT1787usedwithsplitpowersupplies.  
The VBIAS pin is connected to ground, and the output  
signalappearsattheVOUT pin. Bidirectionalinputcurrents  
can be monitored with the output swinging positive for  
–128  
0
64 96  
–96 –64 –32  
32  
128  
+
SENSE VOLTAGE (V – V ) (mV)  
S
S
+
1787 F03  
current flow from VS and VS . Input currents in the  
opposite direction cause VOUT to swing below ground.  
Figure 2 shows an optional output capacitor connected  
from VOUT to ground. This capacitor may be used to filter  
the output signal before it is processed by other  
circuitry.Figure 3 shows the voltage transfer function of  
the LT1787 used in this configuration.  
Figure 3. Split Supply Output Voltage  
R
SENSE  
TO  
CHARGER/  
LOAD  
3.3V  
C1  
1µF  
TO  
60V  
1
8
+
+
FIL  
FIL  
3.3V  
LT1787HV  
V
V
S
2
3
S
7
6
20k  
5%  
V
R
Single Supply with Shifted VBIAS  
BIAS  
DNC  
C2  
1µF  
OUT  
Figure 4 shows the LT1787 used in a single supply mode  
with the VBIAS pin shifted positive using an external  
LT1634 voltage reference. The VOUT output signal can  
swing above and below VBIAS to allow monitoring of  
positive or negative currents through the sense resistor,  
asshowninFigure5.Thechoiceofreferencevoltageisnot  
critical except for the precaution that adequate headroom  
must be provided for VOUT to swing without saturating the  
internal circuitry. The component values shown in Figure 4  
allow operation with VS supplies as low as 3.1V.  
LT1634-1.25  
4
5
V
EE  
V
OUT  
C3*  
1000pF  
1787 F04  
*OPTIONAL  
OUTPUT  
Figure 4. Charge/Discharge Current Monitor on  
Single Supply with V  
= 1.25V  
BIAS  
1.5  
V
= 3.3V TO 60V  
= 40°C TO 85°C  
S
A
T
1.0  
0.5  
R
SENSE  
TO  
CHARGER/  
LOAD  
C1  
1µF  
15V  
1
8
+
+
FIL  
FIL  
0
LT1787  
V
S
V
S
2
3
7
6
–0.5  
–1.0  
–1.5  
V
R
BIAS  
DNC  
OUT  
4
5
V
EE  
OUTPUT  
V
OUT  
–128  
0
64 96  
C2  
1µF  
–96 –64 –32  
32  
128  
C3*  
1000pF  
–5V  
+
SENSE VOLTAGE (V – V ) (mV)  
S
S
1787 F05  
1787 F02  
*OPTIONAL  
Figure 5. Single Supply Output Voltage  
with V = 1.25V  
Figure 2. Split Supply Operation  
BIAS  
1787fc  
11  
LT1787/LT1787HV  
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APPLICATIONS INFORMATION  
R
SENSE  
Operation with A/D Converter  
5V  
C1  
5V  
Figure 6 shows the LT1787 operating with the LTC1286  
A/D converter. This low cost circuit is capable of 12-bit  
resolution of unipolar currents. The IN pin of the A/D  
converter is biased at 1V by the resistor divider R1 and R2.  
Thisvoltageincreasesassensecurrentincreases, withthe  
amplified sense voltage appearing between the A/D con-  
verters –IN and +IN terminals. The front page of the data  
sheet shows a similar circuit which uses a voltage refer-  
enceforimprovedaccuracyandsignalrange.TheLTC1286  
converter uses sequential sampling of its –IN and +IN  
inputs. Accuracy is degraded if the inputs move between  
sampling intervals. A filter capacitor from FIL+ to FILas  
well as a filter capacitor from VBIAS to VOUT may be  
necessary if the sensed current changes more than 1LSB  
within a conversion cycle.  
1µF  
1
8
+
+
FIL  
FIL  
LT1787  
R1  
20k  
5%  
V
V
S
2
3
S
7
6
I
V
OUT  
BIAS  
DNC  
R
OUT  
V
4
5
CC  
CS  
V
+IN  
–IN  
EE  
V
OUT  
LTC1286 CLK  
TO µP  
D
OUT  
V
R2  
5k  
GND  
REF  
1787 F06  
5%  
Figure 6. Unidirectional Output into A/D  
+
with Fixed Supply at V  
S
I
SENSE  
R
TO  
CHARGER/  
LOAD  
SENSE  
C1  
1µF  
2.5V + V  
SENSE(MAX)  
1
8
+
+
FIL  
FIL  
Buffered Output Operation  
LT1787  
V
V
S
2
3
S
7
6
Figure 7 shows the LT1787’s outputs buffered by an  
operational amplifier configured as an I/V converter. This  
configuration is ideal for monitoring very low voltage  
supplies. The LT1787’s VOUT pin is held equal to the  
reference voltage appearing at the op amp’s noninverting  
input. This allows monitoring VS supplies as low as 2.5V.  
Theopamp’soutputmayswingfromgroundtoitspositive  
supply voltage. The low impedance output of the op amp  
maydrivefollowingcircuitrymoreeffectivelythanthehigh  
outputimpedanceoftheLT1787.TheI/Vconverterconfigu-  
ration also works well with split supply voltages.  
2.5V  
V
BIAS  
DNC  
C3  
1000pF  
R
OUT  
4
5
V
EE  
V
OUT  
A1  
V
OUT A  
2.5V  
+
LT1495  
1M  
5%  
LT1389-1.25  
1787 F07  
Figure 7. Single Supply 2.5V Bidirectional Operation  
with External Voltage Reference and I/V Converter  
Single Supply Unidirectional Operation  
R
SENSE  
C
TO  
LOAD  
Figure 8 shows the simplest connection in which the  
LT1787 may be used. The VBIAS pin is connected to  
ground, and the VOUT pin swings positive with increasing  
sense current. The LT1787’s outputs can swing as low as  
30mV as shown in Figure 9. Accuracy is sacrificed at small  
output levels, but this is not a limitation in protection  
circuit applications or where sensed currents do not vary  
greatly. Increased low level accuracy can be obtained by  
levelshiftingVBIAS aboveground.Thelevelshiftingmaybe  
done with resistor dividers, voltage references or a simple  
diode. Accuracy is ensured if the output signal is sensed  
2.5V TO  
60V  
0.1µF  
1
8
+
+
FIL  
FIL  
LT1787HV  
V
V
S
2
3
S
7
6
V
R
BIAS  
DNC  
OUT  
4
5
V
V
EE  
OUT  
V
OUT  
1787 F08  
Figure 8. Unidirectional Current Sensing Mode  
differentially between VBIAS and VOUT  
.
1787fc  
12  
LT1787/LT1787HV  
U
W U U  
APPLICATIONS INFORMATION  
0.30  
resistor. When an external resistor is used, leave the VBIAS  
pin floating or connected to the VOUT pin. This will remove  
the internal ROUT from the circuit.  
0.25  
0.20  
0.15  
0.10  
0.05  
The voltage gain will be gm • ROUT where gm is the  
LT1787’s transconductance, 400µA/V typical. A nominal  
gain of 40 may be obtained with an external 100k resistor  
used in place of the internal 20k ROUT  
:
AV = gm • ROUT = 400µA/V • 100k = 40  
IDEAL  
0
The transconductance gm is set by on-chip resistors on  
the LT1787. These resistors match well but have loose  
absolute tolerance. This will normally require that the  
external gain setting resistor be trimmed for initial accu-  
racy. After trimming, the temperature stability of the gm  
and therefore gain will be –200ppm/°C.  
0
0.010 0.015 0.020 0.025 0.030  
0.005  
+
V
S
– V (V)  
S
1787 F09  
Figure 9. Expanded Scale of Unidirectional Output  
Adjusting Gain Setting  
Theonlylimitationsplacedupontheresistorchoiceiscare  
must be taken not to saturate the internal circuitry by  
violating the VOMAX specification of VS + –0.75V.  
The LT1787 may be used in all operating modes with an  
external resistor used in place of the internal 20k ROUT  
1787fc  
13  
LT1787/LT1787HV  
U
PACKAGE DESCRIPTION  
MS8 Package  
8-Lead Plastic MSOP  
(LTC DWG # 05-08-1660)  
0.889 ± 0.127  
(.035 ± .005)  
5.23  
(.206)  
MIN  
3.20 – 3.45  
(.126 – .136)  
3.00 ± 0.102  
(.118 ± .004)  
(NOTE 3)  
0.52  
(.0205)  
REF  
0.65  
(.0256)  
BSC  
0.42 ± 0.038  
(.0165 ± .0015)  
TYP  
8
7 6  
5
RECOMMENDED SOLDER PAD LAYOUT  
3.00 ± 0.102  
(.118 ± .004)  
(NOTE 4)  
4.90 ± 0.152  
(.193 ± .006)  
DETAIL “A”  
0° – 6° TYP  
0.254  
(.010)  
GAUGE PLANE  
1
2
3
4
0.53 ± 0.152  
(.021 ± .006)  
1.10  
(.043)  
MAX  
0.86  
(.034)  
REF  
DETAIL “A”  
0.18  
(.007)  
SEATING  
PLANE  
0.22 – 0.38  
0.127 ± 0.076  
(.009 – .015)  
(.005 ± .003)  
0.65  
(.0256)  
BSC  
TYP  
MSOP (MS8) 0204  
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  
1787fc  
14  
LT1787/LT1787HV  
U
PACKAGE DESCRIPTION  
S8 Package  
8-Lead Plastic Small Outline (Narrow 0.150)  
(LTC DWG # 05-08-1610)  
.189 – .197  
(4.801 – 5.004)  
.045 ±.005  
.160 ±.005  
NOTE 3  
.050 BSC  
7
5
8
6
.245  
MIN  
.150 – .157  
(3.810 – 3.988)  
NOTE 3  
.228 – .244  
(5.791 – 6.197)  
.030 ±.005  
TYP  
1
3
4
2
RECOMMENDED SOLDER PAD LAYOUT  
.010 – .020  
(0.254 – 0.508)  
× 45°  
.053 – .069  
(1.346 – 1.752)  
.004 – .010  
(0.101 – 0.254)  
.008 – .010  
(0.203 – 0.254)  
0°– 8° TYP  
.016 – .050  
(0.406 – 1.270)  
.050  
(1.270)  
BSC  
.014 – .019  
(0.355 – 0.483)  
TYP  
NOTE:  
INCHES  
1. DIMENSIONS IN  
(MILLIMETERS)  
2. DRAWING NOT TO SCALE  
3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS.  
MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm)  
SO8 0303  
1787fc  
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-  
tationthattheinterconnectionofitscircuitsasdescribedhereinwillnotinfringeonexistingpatentrights.  
15  
LT1787/LT1787HV  
TYPICAL APPLICATION  
U
Split or Single Supply Operation, Bidirectional Output into A/D  
1  
1%  
I
= ±125mA  
S
V
CC  
5V  
1
8
V
+
+
SRCE  
FIL  
FIL  
4.75V  
LT1787  
10µF  
16V  
V
V
S
2
3
S
7
6
V
BIAS  
1
DNC  
7
6
5
CONV  
CLK  
20k  
V
(±1V)  
4
5
OUT  
2
V
EE  
–5V  
CLOCKING  
CIRCUITRY  
V
A
V
LTC1404  
REF  
GND  
EE  
IN  
3
V
OUT  
OPTIONAL SINGLE  
SUPPLY OPERATION:  
DISCONNECT V  
DOUT  
10µF  
16V  
BIAS  
FROM GROUND  
AND CONNECT IT TO V  
4
8
10µF  
16V  
.
D
REF  
OUT  
REPLACE –5V SUPPLY  
WITH GROUND.  
OUTPUT CODE FOR ZERO  
CURRENT WILL BE ~2430  
V
EE  
–5V  
1787 TA02  
RELATED PARTS  
PART NUMBER  
DESCRIPTION  
COMMENTS  
LTC1043  
Dual Precision Instrumentation Switched Capacitor Building Block  
Dual and Quad Micropower Rail-to-Rail Input and Output Op Amps  
120dB CMRR, 3V to 18V Operation  
LT1490/LT1491  
50µA Amplifier, 2.7V to 40V Operation,  
Over-The-TopTM Inputs  
LT1620/LT1621  
Rail-to-Rail Current Sense Amplifiers  
Accurate Output Current Programming, Battery  
Charging to 32V  
Over-The-Top is a trademark of Linear Technology Corporation.  
1787fc  
LT 0606 REV C • PRINTED IN USA  
LinearTechnology Corporation  
1630 McCarthy Blvd., Milpitas, CA 95035-7417  
16  
(408) 432-1900 FAX: (408) 434-0507 www.linear.com  
© LINEAR TECHNOLOGY CORPORATION 1999  

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