ltc2493 Linear Technology Corporation, ltc2493 Datasheet - Page 11

• Manufacturer Part Number: ltc2493
• Description: 24-bit 2-/4-channel Delta Sigma Adc With Easy Drive Input Current Cancellation And I2c Interface
• Manufacturer: Linear Technology Corporation

pin FuncTions
F
the internal conversion clock rate. When F
to GND, the converter uses its internal oscillator running at
307.2kHz. The conversion clock may also be overridden by
driving the F
the output rate and the digital filter rejection null.
CA0, CA1 (Pins 2, 3): Chip Address Control Pins. These
pins are configured as a three-state (LOW, HIGH, Floating)
address control bits for the device’s I
SCL (Pin 4): Serial Clock Pin of the I
LTC2493 can only act as a slave and the SCL pin only ac-
cepts an external serial clock. Data is shifted into the SDA
pin on the rising edges of the SCL clock and output through
the SDA pin on the falling edges of the SCL clock.
SDA (Pin 5): Bidirectional Serial Data Line of the I
face. In the transmitter mode (Read), the conversion result
is output through the SDA pin, while in the receiver mode
(Write), the device channel select and configuration bits
are input through the SDA pin. The pin is high impedance
during the data input mode and is an open drain output
(requires an appropriate pull-up device to V
data output mode.
GND (Pin 6): Ground. Connect this pin to a common ground
plane through a low impedance connection.
O
(Pin 1): Frequency Control Pin. Digital input that controls
O
pin with an external clock in order to change
2
C address.
2
C Interface. The
O
CC
is connected
) during the
2
C Inter-
COM (Pin 7): The Common Negative Input (IN
Single-Ended Multiplexer Configurations. The voltage
on CH0-CH3 and COM pins can have any value between
GND – 0.3V to V
selected inputs (IN
range (V
Outside this input range, the converter produces unique
over-range and under-range output codes.
CH0 to CH3 (Pin 8-Pin 11): Analog Inputs. May be pro-
grammed for single-ended or differential mode.
V
a 10µF tantalum capacitor in parallel with a 0.1µF ceramic
capacitor as close to the part as possible.
REF
The voltage on these pins can have any value between
GND and V
remains more positive than the negative reference input,
REF
– REF
Exposed Pad (Pin 15): Ground. This pin is ground and
must be soldered to the PCB ground plane. For prototyping
purposes, this pin may remain floating.
CC
(Pin 12): Positive Supply Voltage. Bypass to GND with
–
+
, by at least 0.1V. The differential voltage (V
, REF
–
) sets the full-scale range for all input channels.
IN
CC
–
= IN
(Pin 13, Pin 14): Differential Reference Input.
as long as the reference positive input, REF
+
CC
– IN
+
+ 0.3V. Within these limits, the two
–
and IN
) from –0.5 • V
–
) provide a bipolar input
REF
LTC2493
to 0.5 • V
REF
–
) for All

= REF
2493fa
REF
+
+
.
,