DATA SHEET
SPT7851
Typical Performance Characteristics
(
T
A
= T
MIN
–T
MAX
, V
DD1
= V
DD2
= V
DD3
= 3.3V, V
REF–
= 1.0V, V
REF+
= 2.0V, Common Mode Voltage = 1.65,
ƒ
CLK
= 20 MSPS,
Bias1 = 90
µ
A, Bias2 = 9.5
µ
A, Differential Input, Duty Cycle = 50%; unless otherwise noted)
THD, SNR, SINAD vs. Input Frequency
80
80
THD, SNR, SINAD vs. Sample Rate
THD, SNR, SINAD (dB)
THD, SNR, SINAD (dB)
70
SNR
THD
70
60
THD
SNR
SINAD
60
50
40
30
20
10
0
10
1
10
2
SINAD
50
40
30
20
10
0
10
1
10
2
NOTE: Bias1 and Bias2 currents
optimized for each sample rate
Input Frequency (MHz)
Sample Rate (MSPS)
THD, SNR, SINAD vs. Temperature
70
150
Power Dissipation vs. Sample Rate
THD, SNR, SINAD (dB)
Power Dissipation (mW)
68
THD
125
100
75
50
25
0
66
64
62
60
SNR
58
SINAD
NOTE: Bias1 and Bias2 currents
optimized for each sample rate
56
-40
-25
0
25
50
70
85
10
0
10
1
10
2
Temperature ( °C)
Sample Rate (MSPS)
Bias2 Voltage vs. Bias2 Current
0.90
IBias2
3
6
9
12
15
VBias2
0.6975
0.7535
0.796
0.8295
0.8595
Bias1 Voltage vs. Bias1 Current
3.4
3.2
3.0
IBias1
30
60
90
120
150
VBias1
2.19
2.53
2.79
3
3.22
0.85
VBias1 (V)
2.8
2.6
2.4
2.2
2.0
0
30
60
90
120
150
180
VBias2 (V)
0.80
0.75
0.70
0.65
0.60
0
3
6
9
12
15
18
IBIAS1 (µA)
IBIAS2 (µA)
4
REV. 1B October 2003
CADEKA [ CADEKA MICROCIRCUITS LLC. ]
