
50MHz to 1000MHz High-Linearity, Serial/
Parallel-Controlled Analog/Digital VGA
Typical Operating Characteristics (continued)
( V CC = +5.0V, HC mode , both attenuators set for maximum gain, P IN = -20dBm, f RF = 200MHz, and T C = +25°C, internal DAC refer-
ence used, unless otherwise noted.)
S21 PHASE CHANGE OVER DIGITAL
GAIN OVER ANALOG ATTENUATOR
60
ATTENUATOR SETTING vs. RF FREQUENCY
22
SETTING vs. RF FREQUENCY
DAC CODE 0
22
GAIN vs. ANALOG ATTENUATOR SETTING
50
17
17
50MHz
40
30
20
10
0
-10
REFERENCED TO HIGH GAIN STATE
POSITIVE PHASE = ELECTRICALLY SHORTER
12
7
2
-3
-8
-13
-18
DAC CODE 32
DAC CODE 128
DAC CODE 64
DAC CODE 256
12
7
2
-3
-8
-13
-18
1000MHz
450MHz
200MHz
50
250
450
650
850
1050
50
250
450
650
850
1050
0
32
64
96
128 160 192
224 256
22
RF FREQUENCY (MHz)
GAIN vs. ANALOG ATTENUATOR SETTING
RF = 200MHz
22
RF FREQUENCY (MHz)
GAIN vs. ANALOG ATTENUATOR SETTING
RF = 200MHz
0
DAC CODE
INPUT MATCH
vs. ANALOG ATTENUATOR SETTING
17
12
7
T C = -40 ° C, +25 ° C, +85 ° C
17
12
7
V CC = 4.75V, 5.00V, 5.25V
-5
-10
2
2
-15
50MHz
1000MHz
200MHz
450MHz
-3
-8
-13
-18
-3
-8
-13
-18
-20
-25
-30
0
32
64
96
128 160 192
224 256
0
32
64
96
128 160 192
224 256
0
32
64
96
128 160 192
224 256
DAC CODE
OUTPUT MATCH
vs. ANALOG ATTENUATOR SETTING
DAC CODE
REVERSE ISOLATION OVER ANALOG
ATTENUATOR SETTING vs. RF FREQUENCY
DAC CODE
S21 PHASE CHANGE
vs. ANALOG ATTENUATOR SETTING
0
-30
80
70
REFERENCED TO HIGH GAIN STATE
POSITIVE PHASE = ELECTRICALLY SHORTER
-5
-10
450MHz
1000MHz
-40
DAC CODE 0
60
50
1000MHz
450MHz
-15
-50
DAC CODE 255
40
30
-20
20
200MHz
-25
50MHz
200MHz
-60
10
0
-30
-70
-10
50MHz
0
32
64
96
128 160 192
224 256
50
250
450
650
850
1050
0
32
64
96
128 160 192 224 258
DAC CODE
RF FREQUENCY (MHz)
DAC CODE
_______________________________________________________________________________________
7