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TEMIC Semiconductors |
Time Code Receiver
U4224B
Description
The U4224B is a bipolar integrated straight through receiver circuit in the frequency range of 40 to 80 kHz.
The device is designed for radio controlled clock applications.
Features
D Very low power consumption
D Very high sensitivity
D High selectivity by using two crystal filters
D Power down mode available
D Only a few external components necessary
D Digitalized serial output signal
D AGC hold mode
Block Diagram
GND 3
VCC 1
PON
15
Power Supply
TCO
16
93 7727 e
Decoder
11 FLB
10 FLA
9 DEC
IN 2
AGC
Amplifier
4 5 6 13
SB Q1A Q1B Q2A
14
Q2B
Rectifier & 12 SL
Integrator
7
REC
8
INT
TELEFUNKEN Semiconductors
Rev. A3, 02-Apr-96
1 (17)
U4224B
Pin Description
Pin Symbol
SO 16 L
1 VCC
2 IN
3 GND
4 SB
5 Q1A
6 Q1B
7 REC
8 INT
9 DEC
10 FLA
11 FLB
12 SL
13 Q2A
14 Q2B
15 PON
16 TCO
Function
Supply voltage
Amplifier – Input
Ground
Bandwidth control
Crystal filter 1
Crystal filter 1
Rectifier output
Integrator output
Decoder input
Low pass filter
Low pass filter
AGC hold mode
Crystal filter 2
Crystal filter 2
Power ON/OFF control
Time code output
VCC 1
IN 2
16 TCO
15 PON
GND 3
14 Q2B
SB 4
Q1A 5
U4224B
13 Q2A
12 SL
Q1B 6
11 FLB
REC 7
10 FLA
INT 8
9 DEC
93 7729 e
IN SB
A ferrite antenna is connected between IN and VCC. For
high sensitivity the Q of the antenna circuit should be as
high as possible, but a high Q often requires temperature
compensation of the resonant frequency. Specifications
are valid for Q > 30. An optimal signal to noise ratio will
Wbe achieved by a resonant resistance of 50 to 200 k .
A resistor RSB is connected between SB and GND. It con-
trols the bandwidth of the crystal filters. It is
Wrecommended: RSB = 0 for DCF 77.5 kHz, RSB =
W10 k for 60 kHz WWVB and RSB = open for JG2AS
40 kHz.
94 8381
VCC
SB
IN
GND
94 8379
2 (17)
TELEFUNKEN Semiconductors
Rev. A3, 02-Apr-96
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