23

LTC1286/LTC1298

A “Quick Look” Circuit for the LTC1286

Users can get a quick look at the function and timing of the

LT1286 by using the following simple circuit (Figure 13).

–IN input is tied to the ground. CS is driven at 1/16 the

oscilloscope that is set up to trigger on the falling edge of

CS (Figure 14). Note the LSB data is partially clocked out

before CS goes high.

Micropower Battery Voltage Monitor

A common problem in battery systems is battery voltage

monitoring. This circuit monitors the 10 cell stack of NiCad

or NiMH batteries found in laptop computers. It draws only

67

55

µA from the battery. The 12-bits of resolution of the

LTC1286 are positioned over the desired range of 8V to

16V. This is easily accomplished by using the ADC’s

differential inputs. Tying the –input to the reference gives

resistor divider then scales the input voltage for 8V to 16V.

Figure 13. “Quick Look” Circuit for the LTC1286

CLR

CLK

A

B

C

D

P

GND

RC

QA

QB

QC

QD

T

LOAD

74C161

TO OSCILLOSCOPE

CLOCK IN 250kHz

LTC1286/98 F13

CLK

LTC1286

+IN

–IN

GND

4.7

µF

5V

5V

CS

Figure 14. Scope Trace the LTC1286 “Quick Look” Circuit

Figure 15. Micropower Battery Voltage Monitor

39k

5V

LT1004-2.5

200k

91k

3

Ω

BATTERY MONITOR

INPUT 8V TO 16V

1

µF

0.1

µF

CS

CLK

LTC1286

LTC1286/98 F15

–IN

GND

+IN

MSB

(B11)

VERTICAL: 5V/DIV

HORIZONTAL: 10µs/DIV

LSB

(B0)

NULL

BIT

LTC1286/98 F14

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 circuits as described herein will not infringe on existing patent rights.