LTC1279 LINER [Linear Technology], LTC1279 Datasheet - Page 7

• Manufacturer Part Number: LTC1279
• Description: 12-Bit, 600ksps Sampling A/D Converter with Shutdown
• Manufacturer: LINER [Linear Technology]

PI FU CTIO S
FU CTIO AL BLOCK DIAGRA
A
(Bipolar).
V
(10 F tantalum in parallel with 0.1 F ceramic).
AGND (Pin 3): Analog Ground.
D11 to D4 (Pins 11 to 4): Three-State Data Outputs.
D11 is the Most Significant Bit.
DGND (Pin 12): Digital Ground.
D3 to D0 (Pins 13 to 16): Three-State Data Outputs.
DV
SHDN (Pin 18): Power Shutdown. The LTC1279 pow-
ers down when SHDN is low.
CONVST (Pin 19): Conversion Start Input. It is active
low. The falling edge of the CONVST signal initiates a
IN
REF
U
DD
U
(Pin 1): Analog Input. 0V to 5V (Unipolar), 2.5V
(Pin 2): 2.42V Reference Output. Bypass to AGND
(Pin 17 ): Digital Power Supply, 5V. Tie to AV
DGND
U
AGND
V
A
REF
IN
U
U
2.42V REF
INTERNAL
CLOCK
SHDN
12-BIT CAPACITIVE DAC
SUCCESSIVE APPROXIMATION
CONTROL LOGIC
CONVST
REGISTER
C
SAMPLE
12
RD
W
DD
CS
pin.
BUSY
12
conversion. The LTC1279 responds to CONVST signal
only if the signal applied to CS is a logic low.
RD (Pin 20): READ Input. A logic low signal applied to
this pin enables the output data drivers when the signal
applied to the CS pin is a logic low.
CS (Pin 21): The CHIP SELECT input must be a logic low
for the ADC to recognize the signals applied to the
CONVST and RD inputs.
BUSY (Pin 22): The BUSY output shows the converter
status. It is a logic low during a conversion.
V
operation. Bypass to AGND with 0.1 F ceramic. Tie to
analog ground to select unipolar operation.
AV
(10 F tantalum in parallel with 0.1 F ceramic).
SS
COMPAR-
ATOR
DD
ZEROING
SWITCH
(Pin 23): Negative Supply. – 5V will select bipolar
(Pin 24): Positive Supply, 5V. Bypass to AGND
OUTPUT LATCHES
1279 BD
AV
DV
V
(0V FOR UNIPOLAR MODE
OR –5V FOR BIPOLAR MODE)
SS
DD
DD
•
•
•
D11
D0
LTC1279
7