Datasheet

LTC2480
12
2480fe
For more information www.linear.com/LTC2480
PIN FUNCTIONS
SCK (Pin 9): Bidirectional Digital Clock Pin. In internal
serial clock operation mode, SCK is used as the digital
output for the internal serial interface clock during the
data input/output period. In external serial clock operation
mode, SCK is used as the digital input for the external se
-
rial interface clock during the data output period. A weak
internal pull-up is automatically activated in internal serial
clock operation mode. The serial clock operation mode
is
determined
by the logic level applied to the SCK pin at
power up or during the most recent falling edge of CS.
f
O
(Pin 10): Frequency Control Pin. Digital input that
controls the conversion clock. When f
O
is connected to
GND the converter uses its internal oscillator running at
307.2kHz. The conversion clock may also be overridden by
driving the f
O
pin with an external clock in order to change
the output rate or the digital filter rejection null.
GND (Exposed Pad Pin 11): This pin is ground and should
be soldered to the PCB ground plane. For prototyping
purposes, this pin may remain floating.
FUNCTIONAL BLOCK DIAGRAM
1
9
4
5
7
6
10
3RD ORDER
∆Σ ADC
REF
+
IN
+
IN
+
3
V
REF
IN
–
IN
–
REF
–
(1-256)
GAIN
SERIAL
INTERFACE
TEMP
SENSOR
MUX
SDI
2
V
CC
8
GND
CS
f
O
2480 FD
SCK
SD0
AUTOCALIBRATION
AND CONTROL
INTERNAL
OSCILLATOR
TEST CIRCUITS
1.69k
SDO
2480 TA02
Hi-Z TO V
OH
V
OL
TO V
OH
V
OH
TO Hi-Z
C
LOAD
= 20pF
1.69k
SDO
2480 TA03
Hi-Z TO V
OL
V
OH
TO V
OL
V
OL
TO Hi-Z
C
LOAD
= 20pF
V
CC