LTC1446/LTC1446L
U
TYPICAL APPLICATIONS N
This circuit shows how to use one LTC1446 to make an
autoranging ADC. The microprocessor sets the reference
span and the Common pin for the analog input by loading
the appropriate digital code into the LTC1446. VOUT A
controls the Common pin for the analog inputs to the
LTC1296andVOUTB controlsthereferencespanbysetting
the REF+ pin on the LTC1296. The LTC1296 has a Shut-
down pin that goes low in shutdown mode. This will turn
off the PNP transistor supplying power to the LTC1446.
The resistor and capacitor on the LTC1446 outputs act as
a lowpass filter for noise.
An Autoranging 8-Channel ADC with Shutdown
22µF
5V
V
CC
CH0
CS
D
OUT
8 ANALOG
INPUT CHANNELS
CLK
LTC1296
µP
D
IN
CH7
COM
+
REF
–
SSO REF
74HC04
50k
50k
5V
0.1µF
2N3906
100Ω
V
OUT B
CLK
0.1µF
V
CC
D
IN
LTC1446
GND
CS/LD
100Ω
D
OUT
V
OUT A
1446/46L F03
0.1µF
10
Linear [ Linear ]
