Datasheet
LTC2480
11
2480fd
Typical perForMance characTerisTics
Offset Error vs V
CC
(2x Speed Mode)
Offset Error vs V
REF
(2x Speed Mode)
PSRR vs Frequency at V
CC
(2x Speed Mode)
PSRR vs Frequency at V
CC
(2x Speed Mode)
PSRR vs Frequency at V
CC
(2x Speed Mode)
V
CC
(V)
2 2.5
0
OFFSET ERROR (µV)
100
250
3
4
4.5
2480 G41
50
200
150
3.5
5
5.5
V
REF
= 2.5V
V
IN
= 0V
V
IN(CM)
= GND
f
O
= GND
T
A
= 25°C
V
REF
(V)
0
OFFSET ERROR (µV)
190
200
210
3
5
2480 G42
180
170
160
1 2 4
220
230
240
V
CC
= 5V
V
IN
= 0V
V
IN(CM)
= GND
f
O
= GND
T
A
= 25°C
FREQUENCY AT V
CC
(Hz)
1
0
–20
–40
–60
–80
–100
–120
–140
1k 100k
2480 G43
10 100
10k 1M
REJECTION (dB)
V
CC
= 4.1V DC
REF
+
= 2.5V
REF
–
= GND
IN
+
= GND
IN
–
= GND
f
O
= GND
T
A
= 25°C
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