Z8615 Datasheet, PDF (8/10 Pages) Zilog, Inc. – NMOSZ8 8-BITMCU KEYBOARD CONTROLLER

TEST CONDITIONS AND METHODOLOGY
Z8615
CPS DC-4143-05
1. Title:
Z08615CA UTB Frequency-POR Measurement
Procedure.
2. Objective:
To provide instructions for making frequency and POR
measurements.
3. Scope:
All products containing on-board RC oscillator.
4. Applicable Documents:
4.1 Instruction manuals for H-P 8012B Pulse Generator,
H-P 1661A Logic Analyzer, Tektronix DC 503A
Universal Counter/Timer.
4.2 Data Sheet for device under test.
5. Equipment, Materials, and Supplies:
5.1 One UTB (agreed upon by customer).
5.2 One DIN-5 (female) connector or PC (IBM® or
clone) to power the keyboard.
6.2 During frequency measurement, oscillator
input (Pin 3) should not be probed. The internal
circuitry requires that the external impedance on
this node be purely resistive. This is why the input
of the oscillator (Pin 3) is very sensitive to external
loading, then the frequency of the oscillator will be
unstable due to resonance (of loading) excited by
external, as well as internal noise.
To make a frequency reading, connect the scope
probe only to the oscillator out (Pin 2). Even though
this output is well buffered from the oscillator,
loading on this node will affect the period of
oscillation. So use a high-impedance probe to
measure the frequency at this node. The high-
impedance probe serves to minimize waveform
distortion.
6.3 Be consistent in the reading times, e.g., allow the
unit two minutes to warm up before making the
frequency reading. Apply this timing on all parts
tested. Erratic readings will result if the unit's
temperature is not stabilized.
7. Frequency Measurement:
5.3 H-P 8012B Pulse Generator.
5.4 H-P 1661A Logic Analyzer.
5.5 Tektronix DC 503A Universal Counter/Timer and
Tektronix P6202A DC to 500 MHz 10 meg–2 pico
probe.
5.6 H-P 6115A Precision Power Supply.
5.7 A temperature forcing unit (Temptronic
Corporation), or equivalent.
5.8 Golden correlation units.
6. Important Notes:
6.1 The oscillator input/output is sensitive to external
loading, e.g., stray capacitance or inductance.
When making frequency measurement, make sure
the meter probe is on the oscillator output (Pin 2)
only (as close as possible). Any slight loading on
the oscillator input (Pin 3) will cause drastic changes
to the oscillator frequency. Therefore, it is
recommended that the RC resistor be connected
as close as possible to the oscillator input (Pin 3);
and that nothing is hanging on the oscillator input.
7.1 Solder a half-centimeter piece of wire to the UTB
at the oscillator out (Pin 2), then hook the probe to
the wire. Also solder a lesser-than 4" wire to the
device ground (Pin 11), then clip the counter
ground to this. To begin measurement, connect a
5 volt power supply to the UTB. Even though this
output is well buffered from the oscillator, loading
on this node will affect THE FREQUENCY
READOUTS ON THE FREQUENCY COUNTER. So
use the high-impedance probe to properly read
the frequency on the oscillator out.
7.2 Set the temperature forcing unit (at 25°C) directly
above the device. Before taking a reading, give
the part two minutes after power-on to
stabilize under a controlled ambient temperature.
Then take the reading at that instant. Note, if this
timing is not kept consistent from reading to
reading, the frequency reading of a given part can
vary as much as 5% relative to the center frequency.
If a part is still warm from previous measurement,
give it a minute or two to cool to room temperature
before making another measurement. Here,
consistency in cooling time is also important to
minimize drifts in the readings. This drift is caused
by the accumulation of head from the immediate
runs.
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