W91031 Datasheet, PDF (13/29 Pages) Winbond – LOW POWER CMOS INTERGRATED CIRCUIT

Preliminary W91031
Crystal Oscillator
The operation frequency of the W91031 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:
+/- 0.1 % (-40° C to +85° C)
Resonance mode:
Parallel
Load capacitance:
18 pF
Maximum series resistance: 150 Ω
Maximum drive level (mV): 2 mV
(a) W ith crystal osscillator or ceram ic
W91031
OSCI OSCO
3.579545 MHz
(b) W ith other clock
W91031
OSCI OSCO
Oscillator
OSCO
3.579545 MHz
W91031
OSCI OSCO
W91031
OSCI OSCO
Figure 7-9. Some Application of Clock Driven Circuit
Bias Voltage Generator
The bias voltage generator provides a low impedance voltage source equal to VDD/2 and is used to
bias the gain control op-amp. The voltage source is also used for internal circuits. A 0.1 µF capacitor
should be placed between the VREF pin and VSS to reduce noise.
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Publication Release Date: August 2000
Revision A1