Preliminary W91030B
Crystal Oscillator
The operation frequency of the W91030B is 3.579545 MHz. Crystal oscillators, ceramic resonators or
other clock sources can be used. A crystal oscillator or ceramic resonator can be directly connected
to the OSCI and OSCO pins without the need for external components. If other clock sources are
used, the OSCI pin should be driven by a clock source and the OSCO pin used to drive other external
clocked devices, or left open. Figure 7-9 shows some applications.
The crystal specification is as follows:
Frequency:
3.579545 MHz
Frequency tolerance:
Resonance mode:
Load capacitance:
Maximum series resistance:
°
°
+/- 0.1 % (-40 C to +85 C)
Parallel
18 pF
W
150
Maximum drive level (mV): 2 mV
(a) With crystal osscillator or ceramic resonator
W91030B
OSCI
OSCO
3.579545 MHz
(b) With other clock source
W91030B
W91030B
W91030B
OSCO
OSCO
OSCI
OSCI
OSCI
OSCO
Oscillator
OSCO
3.579545 MHz
Figure 7-9. Some Application of Clock Driven Circuit
Bias Voltage Generator
The bias voltage generator provides a low impedance voltage source equal to V /2 and is used to
DD
m
bias the gain control op-amp. The voltage source is also used for internal circuits. A 0.1 F capacitor
had better be placed between the VREF pin and V to reduce noise.
SS
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