AD600JR-REEL7 Analog Devices Inc, AD600JR-REEL7 Datasheet - Page 25

• Manufacturer Part Number: AD600JR-REEL7
• Description: IC AMP VGA DUAL LN 50MA 16SOIC
• Manufacturer: Analog Devices Inc
• Series: X-AMP®r

Specifications of AD600JR-REEL7

• Rohs Status: RoHS non-compliant
• Amplifier Type: Variable Gain
• Number Of Circuits: 2
• Slew Rate: 275 V/µs
• -3db Bandwidth: 35MHz
• Current - Input Bias: 350nA
• Current - Supply: 11mA
• Current - Output / Channel: 50mA
• Voltage - Supply, Single/dual (±): ±4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.300", 7.5mm Width)
• Output Type: -
• Gain Bandwidth Product: -
• Voltage - Input Offset: -

Figure 52 shows V
Figure 53 shows the error ripple due to the individual gain
functions bounded by ±0.2 dB (dotted lines) from 6 μV to 2 V.
The small perturbations at about 200 μV and 20 mV, caused by
the impracticality of matching the gain functions perfectly, are
the only sign that the gains are now sequential. Figure 54 is a
plot of V
rms over the full 120 dB range.
To compare the SNRs in the simultaneous and sequential
modes of operation more directly, all interstage attenuation was
eliminated (R2 and R3 in Figure 47 and R2 in Figure 51), the
input of U1A was shorted, R5 was selected to provide a 20 kHz
bandwidth (R5 = 7.87 kΩ), and only the gain control was
varied, using an external source. The rms value of the noise was
then measured at V
0 dBV, which is almost the maximum output capability of the
AD600. Results for the simultaneous mode can be seen in
Figure 55. The SNR degrades uniformly as the gain is increased.
Note that since the inverting gain control was used, the gain in
this curve and in Figure 56 decreases for more positive values of
the gain-control voltage.
Figure 53. Error Ripple due to the Individual Gain Functions
–0.2
–0.5
–1.0
–1.5
–2.0
–1
–2
–3
–4
–5
2.0
1.5
1.0
0.5
0.2
AGC
5
4
3
2
1
0
0
1µ
1µ
Figure 52. V
that remains very close to its set value of 316 mV
10µ
10µ
LOG
OUT
LOG
100µ
to be linear over a full 120 dB range.
100µ
and expressed as an SNR relative to
Is Linear over the Full 120 dB Range
INPUT SIGNAL (V rms)
INPUT SIGNAL (V rms)
1m
1m
10m
10m
100m
100m
1
1
10
10
Rev. E | Page 25 of 28
In contrast, the SNR for the sequential mode is shown in Figure 56.
U1A always acts as a fixed noise source; varying its gain has no
influence on the output noise. This is a feature of the X-AMP
technique. Therefore, for the first 40 dB of control range
(actually slightly more, as is explained later), when only this
VCA section has its gain varied, the SNR remains constant.
During this time, the gains of U1B and U2A are at their
minimum value of −1.07 dB.
Figure 56. SNR vs. Control Voltage for Sequential Gain Control (See Figure 51)
Figure 55. SNR vs. Control Voltage for Parallel Gain Control (See Figure 47)
400
350
300
250
200
90
80
70
60
50
40
30
20
10
–833.2
90
80
70
60
50
40
30
20
10
–1.183
0
0
1µ
V
Figure 54. V
V
C
C
–625.0
–0.558
SCALE = 31.25mV/dB
SCALE = 10.417mV/dB
316 mV rms over the Full 120 dB Range
10µ
–416.6
0.067
100µ
AGC
Remains Close to Its Setpoint of
–208.3
INPUT SIGNAL (V rms)
0.692
1m
V
V
C
1.317
C
(mV)
0
(V)
10m
208.3
1.942
100m
AD600/AD602
416.6
2.567
625.0
3.192
1
833.2
3.817
10