LTC1446/LTC1446L
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
LTC1296 and VOUT B controls the reference span by setting
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
VCC
CS
CH0
DOUT
8 ANALOG
µP
CLK LTC1296
INPUT CHANNELS
DIN
CH7
COM
REF+
SSO REF –
74HC04
50k
50k
CLK
VOUT B
DIN
VCC
LTC1446
CS/LD
GND
DOUT
VOUT A
2N3906
100Ω
100Ω
5V
0.1µF
0.1µF
0.1µF
1446/46L F03
10