U4065B Datasheet, PDF (4/23 Pages) TEMIC Semiconductors – FM Receiver

U4065B
AGCOUT
10
94 8776
MIXIN1
V_ref
2.5 k
1k
ESD
1V
Output of the automatic gain control:
The AGC output is an open collector output. The current
of the pin diode is this current multiplied by the current
gain of the external PNP transistor. The dc voltage at the
pin may vary from 2 V to V_S, therefore you can easily use
this pin as an indicator of the AGC regulation state.
IMMIXOUT
V_S
ESD
300
11
1V
94 8777
Output of the intermodulation mixer:
W The parallel output resistance is 330 which allows the
use of a standard ceramic BPF without any further match-
ing network. Please ensure that the ground-pin of the filter
is free of ac signals.
AGCWB
V_ref
25 k
32 k
15
ESD
94 8779
Input 1 of the double balanced mixer:
W The parallel input resistance is 1.2 k . The parallel input
capacitance is about 9 pF. When using the mixer unbal-
anced this pin is to be grounded for RF-signals by an
external capacitance of a few nF. DC current is not allowed.
MIXIN2
V_ref
2.5 k
16
ESD
94 8780
Input 2 of the double balanced mixer:
W The parallel input resistance is 1.6 k . The parallel input
capacitance is about 7 pF. The double sideband noise fig-
ure of the unbalanced mixer is about 7 dB. In the balanced
case the noise figure will be reduced by about 0.8 dB.
VREF
V_S
200
94 8781
4.6 V
17
ESD
ESD
13
94 8778
Threshold adjustment of the wideband AGC:
The threshold of the wideband AGC can be adjusted by
an external resistor to ground. The setting range is 10 dB.
For minimum blocking this pin is connected to ground. In
W ^{order to set the threshold to smaller levels the resistance}
value should be up to a few hundred k .
Reference voltage:
The internal temperature compensated reference voltage
is 3.9 V. It is used as bias voltage for most blocks, so the
electrical characteristics of the U4065B are widely inde-
pendent of the supply voltage. The internal output
W resistance of the reference voltage is less than 10 . To
avoid internal coupling across this pin external capacitors
are required. The maximum output current is I_ref = 5 mA.
4 (23)
Rev. A3, 15-Oct-98