U4314B Datasheet, PDF (3/7 Pages) TEMIC Semiconductors – Logarithmic AM Demodulator/RSSI

TELEFUNKEN Semiconductors
U4314B
Electrical Characteristics
V_S = 5 V, T_amb = 25°C, f_in = 10.7 MHz unless otherwise specified. Test circuit see figure 8. IF voltage levels are referred
to the input of the matching network and therefore approximately 5.6 dB higher than referred to Pin 5.
Parameters
Test Conditions / Pins Symbol Min.
Typ.
Max.
Unit
Characteristics
Supply voltage range
Supply current
Bandgap
Pin 8
Pin 8
V_S
3
12
V
I_S
0.8
1.25
mA
Regulated voltage (without
external load)
Source resistance
Output current
External capacitor
Power supply rejection
ratio
f = 50 Hz
Pin 7
Pin 7
Pin 7
Pin 7
Pin 7
V_ref
2.3
2.4
2.5
V
R_ref
2
5
W
I_ref
5
mA
C_ref
4.7
mF
psrr
60
dB
IF amplifier
Input resistance
Pin 5
R_in
200
330
650
W
Input capacitance
Pin 5
C_in
–3 dB limiting point
Pin 5
V_IFin
26
Maximum AM input
Pin 5
V_IFinmax
voltage
AM_out quiescent current
W R_load = 10 k
Pin 4 I_AMout
10
Maximum AM_out current
m V_IFin = 96 dB V,
W R_load = 10 k
I_AMoutmax
Pin 4
75
5
pF
36
46
dBmV
96
dBmV
22
38
mA
105
125
mA
Circuit Description
General functions
The integrated circuit U4314B includes the following
functions: IF-amplifier, logarithmic RSSI / AM demodu-
lator and voltage-regulator.
The 10.7 MHz IF-signal from the front end passes the in-
tegrated IF-amplifier which operates to a logarithmic
RSSI / AM-demodulator. A logarithmic demodulator
was implemented to avoid settling time problems ef-
fected by use of an AGC. The temperature compensated
reference voltage of 2.4 V is externally available. The
value of the external blocking capacitor can be adapted to
the maximum expected load current out of the voltage
regulator. The total supply current is typically 0.8 mA
plus this load current.
1, 2, 3, 6
95 10216
Figure 3. Pin 1, 2, 3, 6 GND
7
95 10219
4
Figure 4. Pin 4 AM_out
Rev. A1: 26.06.1995
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