10

LTC1451

LTC1452/LTC1453

12-Bit 3V to 5V Voltage Output DAC

CLK

CS/LD

µP

0.1

µF

OUTPUT

LTC1451: 0V TO 4.095V

LTC1452: 0V TO 2 • REF

LTC1453: 0V TO 2.5V

LTC1451: 2.048V

LTC1452: EXTERNAL

LTC1453: 1.22V

GND

LTC145X

TO NEXT DAC FOR

DAISY-CHAINING

LTC1451: 4.5V TO 5.5V

LTC1452: 2.7V TO 5.5V

LTC1453: 2.7V TO 5.5V

1451/2/3 TA03

Digitally Programmable Current Source

CLK

CS/LD

µP

0.1

µF

GND

5V

LTC1451

1451/2/3 TA05

–

+

LT1077

Q1

2N3440

410

Ω

≈ 0mA TO 10mA

This circuit shows a digitally programmable current source

from an external voltage source using an external op amp,

an LT1077 and an NPN transistor (2N3440). Any digital

word from 0 to 4095 is loaded into the LTC1451 and its

output correspondingly swings from 0V to 4.095V. In the

configuration shown, this voltage will be forced across the

will range from 0mA at zero-scale to 10mA at full-scale.

of 50

Ω, the voltage source can be as low as 5V.

TYPICAL APPLICATIO S