Datasheet

LTC2481
10
2481fc
PIN FUNCTIONS
REF
+
(Pin 1), REF
–
(Pin 3): Differential Reference Input.
The voltage on these pins can have any value between
GND and V
CC
as long as the reference positive input,
REF
+
, is more positive than the reference negative input,
REF
–
, by at least 0.1V.
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.
IN
+
(Pin 4), IN
–
(Pin 5): Differential Analog Input. 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.
TYPICAL PERFORMANCE CHARACTERISTICS
PSRR vs Frequency at V
CC
(2x Speed Mode)
PSRR vs Frequency at V
CC
(2x Speed Mode)
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)
V
CC
(V)
2.7
0
OFFSET ERROR (µV)
100
250
3
4
4.5
2481 G36
50
200
150
3.5
5
5.5
V
REF
= 2.5V
V
IN
= 0V
V
IN(CM)
= GND
T
A
= 25°C
V
REF
(V)
0
OFFSET ERROR (µV)
190
200
210
3
5
2481 G37
180
170
160
12 4
220
230
240
V
CC
= 5V
V
IN
= 0V
V
IN(CM)
= GND
T
A
= 25°C
FREQUENCY AT V
CC
(Hz)
1
0
–20
–40
–60
–80
–100
–120
–140
1k 100k
2481 G38
10 100
10k 1M
REJECTION (dB)
V
CC
= 4.1V DC
REF
+
= 2.5V
REF
–
= GND
IN
+
= GND
IN
–
= GND
T
A
= 25°C
FREQUENCY AT V
CC
(Hz)
0
–140
RREJECTION (dB)
–120
–80
–60
–40
0
20
100
140
2481 G39
–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
T
A
= 25°C
FREQUENCY AT V
CC
(Hz)
30600
–60
–40
0
30750
2481 G40
–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
T
A
= 25°C