Datasheet

LTC2485
33
2485fc
APPLICATIONS INFORMATION
Figure 40. Input Normal Mode Rejection 2x Speed Mode Figure 41. Input Normal Mode Rejection 2x Speed Mode
Figure 42. Input Normal Mode Rejection
vs Input Frequency, 2x Speed Mode and 50Hz/60Hz Mode
Figure 43. Input Normal Mode Rejection 2x Speed Mode
Figure 44. Calibration Setup
INPUT SIGNAL FREQUENCY (f
N
)
INPUT NORMAL REJECTION (dB)
2485 F40
0
–20
–40
–60
–80
–100
–120
0
f
N
2f
N
3f
N
4f
N
5f
N
6f
N
7f
N
8f
N
INPUT SIGNAL FREQUENCY (f
N
)
INPUT NORMAL REJECTION (dB)
2485 F41
0
–20
–40
–60
–80
–100
–120
250248 252 254 256 258 260 262 264
INPUT FREQUENCY (Hz)
0
NORMAL MODE REJECTION (dB)
50
100
125 225
2485 F42
25 75
150
175
200
0
–20
–40
–60
–80
–100
–120
V
CC
= 5V
V
REF
= 5V
V
INCM
= 2.5V
V
IN(P-P)
= 5V
T
A
= 25°C
MEASURED DATA
CALCULATED DATA
DIFFERENTIAL INPUT SIGNAL FREQUENCY (Hz)
48
–70
–80
–90
–100
–110
–120
–130
–140
54 58
2485 F43
50 52
56 60 62
NORMAL MODE REJECTION (dB)
NO AVERAGE
WITH
RUNNING
AVERAGE
SCL
SDA
CA1
CA0/f
0
6
7
9
10
V
CC
5V
LTC2485
REF
+
GND
IN
–
IN
+
1
ISOTHERMAL
2
C7
0.1µF
1.7k
C8
1µF
4
R2
2k
R7
8k
62
5
4
R8
1k
5
2485 F44
26.3C
TYPE K
THERMOCOUPLE
JACK
(OMEGA MPJ-K-F)
83
REF
–
IN OUT
G1
NC1M4V0
TRIM
GND
LT1236
+
1.7k