AK2124 Datasheet, PDF (6/6 Pages) List of Unclassifed Manufacturers – Receiver/Demodulator for time code signals transmitted by the transmitters

min.
typ.
max.
unit
Control time ( V_SR = V_CC )
for ∆V_i = 0.1 mV - 1 mV
for ∆V_i = 1 mV - 0.5 mV
Control time ( V_SR = 0V )
for ∆V_i = 0.1 mV - 1 mV
for ∆V_i = 1 mV - 0.5 mV
0.8
s
2.0
s
0.8
s
5.0
s
Output pulse width ( V_SR = 0 V )
at transmitter pulse width 200 ms
for V_R = 1.4 V, V_iE = 3 µV
Output current I_OH ( V_R = 6 V )
180
195
220
ms
10
µA
Output current I_OL ( V_R = 6 V )
Output voltage V_OL
( I_OL = 15 µA )
Application Hints
60
200
µA
20
200
mV
1. RF Component
An inductive coupling of signals between E1, E2 and AP1 is essential to establishing the given switch-over
attenuation.
The SA switch-over point is ca. 0.8 V.
The output A2, with an impedance of 7.5 kΩ, has an inverted output signal ca. 5 dB lower than A1.
The filter band width of the quartz filter between A1 and E3 should be set to 20...25 Hz with a series resistance of
330 kΩ. The associated signal attenuation of ca. 12 dB is also desirable when other filter configurations are
applied. When the AK2124 is used as a dual standard receiver, antenna switch-over with SA is necessary, as is
filtering with two different crystals from outputs A1 to E3, or A2 to E3.
2. Demodulator, Control time constants
The demodulated time signal impulses are available at CD. The time constant is CD _* 70 kΩ.
Regulated voltage is attained at the pin CR, whereby the control-time constant is determined by a switchable
decharging circuit and CR.
The control rate is regulated at SR. A larger control-time constant functions at V_SR = O V than at V_SR = V_CC.
To reduce oscillating overdrive the additional connection with a series resistor of 680 Ω on the CR is
recommended.
3. Receiver circuit
The optimal supply voltage is 1.4 V. At applications with a voltage supply above 1.4 V it is better to connect V_CC
with a bias resistor so that there is about 1.4 V, whereby there is a simultaneous dynamic decoupling to other
components. The output is able to bear load resistance with working voltages of up to 5.25 V independent of V_CC.
It is therefore advantageous to block the V_CC - pin with a capacitor > 4.7 µF.
The usual RF-technical aspects are valid for the PCB layout, whereby special attention should be given to the fact
that between A and E3 the greatest possible area is intended for purposes of shielding.