SA5209 Datasheet, PDF (8/17 Pages) NXP Semiconductors – Wideband variable gain amplifier

Philips Semiconductors
Wideband variable gain amplifier
Product specification
SA5209
CRYSTAL
FILTER
+5V
50Ω
SOURCE
50Ω
OUTPUT
5209
V_BG
V_AGC
R₁
R₂
Gain = 19dB + 20log₁₀ V_AGC
50Ω
ƪ ƫ _{where VAGC =}
R₂
R₁ ) R₂
V_BG
and is in units of Volts, for V_AGC ≤ 1V
SR00247
Figure 11. User-Programmable Fixed Gain Block
RF INPUT
50Ω
SOURCE
+5V
5209
V_AGC
.5V
R
9R
FULL CARRIER
AM (DSB)
50Ω
OUTPUT
50Ω
+5V
All harmonic distortion products will be
at least -50dBc over the audio spectrum.
Figure 12. AM Modulator
MODULATING
SIGNAL
SR00248
5209
5209
5209
50Ω
OUTPUT
V_AGC
V_AGC
50Ω
V_AGC
The high input impedance to the NE5209 makes matching
to crystal filters relatively easy. The total delta gain of this
system will approach 80dB. IF frequencies well into the UHF
region can be configured with this type of architecture.
Figure 13. Receiver AGC IF Gain
R_S
V_S ^±
R_T
V_CC (+5V, unless otherwise noted)
5209
R_L
R_T
± _VAGC
R_L
Figure 14. Test Set-up 1 (Used for all Graphs)
GAIN CONTROL
SIGNAL
SR00249
SR00250
1997 Nov 07
8