LTC1453 LINER [Linear Technology], LTC1453 Datasheet - Page 10

• Manufacturer Part Number: LTC1453
• Description: 12-Bit Rail-to-Rail Micropower DACs in SO-8
• Manufacturer: LINER [Linear Technology]

LTC1451
LTC1452/LTC1453
TYPICAL APPLICATIO S
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
10
P
P
U
TO NEXT DAC FOR
DAISY-CHAINING
CLK
D
CS/LD
IN
LTC1451
GND
V
5V
Digitally Programmable Current Source
CC
12-Bit 3V to 5V Voltage Output DAC
LTC1451: 2.048V
LTC1452: EXTERNAL
LTC1453: 1.22V
D
CLK
CS/LD
D
V
IN
OUT
OUT
V
REF
LTC145X
V
CC
0.1 F
LTC1451: 4.5V TO 5.5V
LTC1452: 2.7V TO 5.5V
LTC1453: 2.7V TO 5.5V
GND
+
–
resistor R
will range from 0mA at zero-scale to 10mA at full-scale.
The minimum voltage for V
resistor R
of 50 , the voltage source can be as low as 5V.
LT1077
V
OUT
A
L
V
FOR R
. If R
S
and Q1's V
+ 5V TO 100V
OUTPUT
LTC1451: 0V TO 4.095V
LTC1452: 0V TO 2 • REF
LTC1453: 0V TO 2.5V
0.1 F
L
A
Q1
2N3440
R
R
410
50
1451/2/3 TA05
is chosen to be 410 the output current
L
A
1451/2/3 TA03
I
OUT
CESAT
=
D
4096 • R
IN
• 4.095
S
voltage. With a load resistor
A
is determined by the load
0mA TO 10mA