Datasheet
LTC2480
11
2480fe
For more information www.linear.com/LTC2480
TYPICAL PERFORMANCE CHARACTERISTICS
PSRR vs Frequency at V
CC
(2x Speed Mode)
PSRR vs Frequency at V
CC
(2x Speed Mode)
FREQUENCY AT V
CC
(Hz)
0
–140
RREJECTION (dB)
–120
–80
–60
–40
0
20
100
140
2480 G44
–100
–20
80
180
220200
40
60
120 160
V
CC
= 4.1V DC ±1.4V
REF
+
= 2.5V
REF
–
= GND
IN
+
= GND
IN
–
= GND
f
O
= GND
T
A
= 25°C
FREQUENCY AT V
CC
(Hz)
30600
–60
–40
0
30750
2480 G45
–80
–100
30650 30700 30800
–120
–140
–20
REJECTION (dB)
V
CC
= 4.1V DC ±0.7V
REF
+
= 2.5V
REF
–
= GND
IN
+
= GND
IN
–
= GND
f
O
= GND
T
A
= 25°C
PIN FUNCTIONS
SDI (Pin 1): Serial Data Input. This pin is used to select
the GAIN, line frequency rejection, input, temperature
sensor and 2x speed mode. Data is shifted into the SDI
pin on the rising edge of serial clock (SCK).
V
CC
(Pin 2): Positive Supply Voltage. Bypass to GND (Pin 8)
with a 1µF tantalum capacitor in parallel with 0.1µF ceramic
capacitor as close to the part as possible.
V
REF
(Pin 3): Positive Reference Input. The voltage on
this pin can have any value between 0.1V and V
CC
. The
negative reference input is GND (Pin 8).
IN
+
(Pin 4), IN
–
(Pin 5): Differential Analog Inputs. The
voltage on these pins can have any value between GND
– 0.3V and V
CC
+ 0.3V. Within these limits the converter
bipolar input range (V
IN
= IN
+
– IN
–
) extends from –0.5
• V
REF
/GAIN to 0.5 • V
REF
/GAIN. Outside this input range
the converter produces unique overrange and underrange
output codes.
CS (Pin 6): Active LOW Chip Select. A LOW on this pin
enables the digital input/output and wakes up the ADC.
Following each conversion the ADC automatically enters
the sleep mode and remains in this low power state as
long as CS is HIGH. A LOW-to-HIGH transition on CS
during the data output transfer aborts the data transfer
and starts a new conversion.
SDO (Pin 7): Three-State Digital Output. During the data
output period, this pin is used as the serial data output.
When the chip select CS is HIGH (CS = V
CC
), the SDO pin
is in a high impedance state. During the conversion and
sleep periods, this pin is used as the conversion status
output. The conversion status can be observed by pulling
CS LOW.
GND (Pin 8): Ground. Shared pin for analog ground, digital
ground and reference ground. Should be connected directly
to a ground plane through a minimum impedance.