U4221B Datasheet, PDF (2/12 Pages) TEMIC Semiconductors – Radio Controlled Clock Receiver

U4221B
Pin Description
Pin Symbol
Function
1
IN2 Amplifier 1 - Input 2
2
IN1 Amplifier 1 - Input 1
3
GND Analog ground
4
CAGC Time constant of AGC
5 CDEM Low pass filter
6
INA2 Amplifier 2 input
7
GND Digital ground
8 OUTA1 Amplifier 1 output
9
V_CCD Supply voltage (digital)
10
NC Not connected
11
FSS Field strength select
12
FSI Field strength indication
13
TCO Time code output
14
PON Power ON/OFF control
15
GND Ground (substrate)
16
V_CCA Supply voltage (analog)
IN2 1
IN1 2
16 ^VCCA
15 ^GND
GND ³
14 PON
CAGC ⁴
CDEM 5
U 4221 B
13 TCO
12 FSI
INA2 6
11 FSS
GND 7
10 NC
OUTA1 8
9 ^VCCD
93 7507 e
IN1, IN2
IN2 is connected to Pin 16 (V_CCA). A ferrite antenna is
connected between IN1 and IN2. Q of antenna circuit
should be as high as possible, but the temperature
influence must be compensated. The resonant resistance
W W should be 200 k to 300 k for optimal sensitivity.
OUTA1, INA2
To achieve a high selectivity, a quartz resonator is
connected between the pins OUTA1 and INA2. It is used
with the serial resonance frequency of the time code
transmitter (e.g. 60 kHz WWVB, 77.5 kHz DCF). The
parasitic parallel capacitance C₀ of the quartz resonator
should be 0.5 pF to 1 pF.
CAGC
A control voltage derived from the field strength is
generated to control the amplifiers. The time constant of
this automatic gain control (AGC) is influenced by the
capacitor CAGC.
CDEM
After demodulation the signal is low pass filtered by the
capacitor CDEM.
PON
If PON is connected to V_CCD, the U4221B receiver IC
will be activated. The set-up time is typical 2.5 s after ap-
plying V_CCD at this pin. If PON is connected to GND, the
receiver will go into stop mode.
FSS
This pin is connected to GND, otherwise the field strength
indication FSI is disabled.
FSI
m ^{If the voltage at the input of amplifier 1 is higher than}
about 5 V, FSI will be high.
2 (12)
TELEFUNKEN Semiconductors
Preliminary Information
Rev. A1, 15-May-96