U4065B Datasheet, PDF (3/23 Pages) TEMIC Semiconductors – FM Receiver

IF2OUT
V_S
3
ESD
U4065B
W The parallel input resistance is 330 . The parallel input
capacitance is about 12 pF. No dc current is allowed. To
avoid overload of this stage an internal detector watches
the input level and causes current at the AGCOUT pin.
IF1OUT
V_ref
94 8771
Output of the second IF amplifier:
The parallel output capacitance to ground is about 7 pF.
The external load resistance is to connect to V_S. The dc
current into the pin is typically 3 mA.
Note: Supply voltage V_S has to be protected against
IF-distortion
GAINIF1
V_S
ESD
330
7
94 8774
17 V_ref
Output of the first IF amplifier:
2 kW
ESD
4
94 8772
Gain control of the first IF amplifier:
The gain of the first IF amplifier can be adjusted by a re-
sistor to ground. This is useful for example to com-
pensate the insertion loss tolerances of the ceramic BPF’s.
Please ensure that the output current of the pin does not
m exceed 150 A in any case. Linear increasing in the cur-
rent out of GAINIF1 effects dB linear increasing of the
m gain (0.15 dB/ A).
Ã¥ I4 = 0
G= Gmin = 2 dB
m å I4 = 140 A G = Gmax = 22 dB
IF2IN
V_ref
94 8773
W The parallel output resistance is 330 which allows the
use of a standard ceramic BPF. The parallel output capa-
citance is about 7 pF. The dc voltage at the pin is 0.5 V
less than V_S.
IMIFIN
94 8775
9
ESD
Input of the IF amplifier for the IM-sensor:
5
ESD
Input of the second IF amplifier:
W The parallel input resistance is 330 . The amplifier is ex-
m tremely sensitive to ac signals. A few hundred V of
IF-signal at this pin will cause current at the AGC output.
Therefore pay attention when connecting the standard ce-
ramic filter used between IMOUT and this pin. The
reference point of the filter has to be free of any ac signal.
Please avoid dc current at this pin.
Rev. A3, 15-Oct-98
3 (23)