9

LT1787/LT1787HV

Figure 3. Split Supply Output Voltage

S

1787 F03

1.5

1.0

0.5

0

–0.5

–1.0

–1.5

–128

–64

0

32

–96

–32

64

96

128

S

1787 F05

1.5

1.0

0.5

0

–0.5

–1.0

–1.5

–128

–64

0

32

–96

–32

64

96

128

Figure 5. Single Supply Output Voltage

Figure 2. Split Supply Operation

*OPTIONAL

C2

1

µF

–5V

1787 F02

OUTPUT

C3*

1000pF

C1

1

µF

15V

TO

CHARGER/

LOAD

1

2

3

4

8

7

6

5

LT1787

–

+

DNC

Figure 4. Charge/Discharge Current Monitor on

C2

1

µF

20k

5%

1787 F04

3.3V

LT1634-1.25

*OPTIONAL

OUTPUT

C1

1

µF

3.3V

TO

60V

TO

CHARGER/

LOAD

1

2

3

4

8

7

6

5

LT1787HV

–

+

DNC

C3*

1000pF

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-

ence for improved accuracy and signal range. The LTC1286

converter uses sequential sampling of its –IN and +IN

inputs. Accuracy is degraded if the inputs move between

necessary if the sensed current changes more than 1LSB

within a conversion cycle.

Figure 6. Unidirectional Output into A/D

+

R2

5k

5%

1787 F06

C1

1

µF

5V

GND

LTC1286

CS

CLK

+IN

–IN

TO

µP

5V

1

2

3

4

8

7

6

5

LT1787

–

+

DNC

R1

20k

5%