MC68HC908GT16 Datasheet, PDF (390/412 Pages) Motorola, Inc – Microcontrollers

Electrical Specifications
23.12 Trimmed Accuracy of the Internal Clock Generator
The unadjusted frequency of the low-frequency base clock (IBASE),
when the comparators in the frequency comparator indicate zero error,
can vary as much as ±25% due to process, temperature, and voltage.
The trimming capability exists to compensate for process effects. The
remaining variation in frequency is due to temperature, voltage, and
change in target frequency (multiply register setting). These effects are
designed to be minimal, however variation does occur. Better
performance is seen at 3 V and lower settings of N.
23.12.1 2.7-Volt to 3.3-Volt Trimmed Internal Clock Generator Characteristics
Characteristic⁽¹⁾
Symbol
Min
Typ
Max
Unit
Absolute trimmed internal oscillator tolerance^{(2), (3)}
–40°C to 85°C
F_{abs_tol}
—
Variation over temperature^{(3), (4)}
V_{ar_temp}
—
Variation over voltage^{(3), (5)}
25°C
–40°C to 85°C
V_{ar_volt}
—
—
2.5
4.0
%
0.03
0.05
%/°C
0.5
2.0
%/V
0.7
2.0
1. These specifications concern long-term frequency variation. Each measurement is taken over a 1-ms period.
2. Absolute value of variation in ICG output frequency, trimmed at nominal V_DD and temperature, as temperature
and V_DD are allowed to vary for a single given setting of N.
3. Specification is characterized but not tested.
4. Variation in ICG output frequency for a fixed N and voltage
5. Variation in ICG output frequency for a fixed N
23.12.2 4.5-Volt to 5.5-Volt Trimmed Internal Clock Generator Characteristics
Characteristic⁽¹⁾
Symbol
Min
Absolute trimmed internal oscillator tolerance^{(2), (3)}
–40°C to 85°C
F_{abs_tol}
—
Variation over temperature^{(3), (4)}
V_{ar_temp}
—
Variation over voltage^{(3), (5)}
25°C
–40°C to 85°C
V_{ar_volt}
—
—
Typ
4.0
0.05
1.0
1.0
Max
Unit
4.0
%
0.08
%/°C
2.0
%/V
2.0
1. These specifications concern long-term frequency variation. Each measurement is taken over a 1-ms period.
2. Absolute value of variation in ICG output frequency, trimmed at nominal V_DD and temperature, as temperature
and V_DD are allowed to vary for a single given setting of N.
3. Specification is characterized but not tested.
4. Variation in ICG output frequency for a fixed N and voltage
5. Variation in ICG output frequency for a fixed N
Technical Data
390
MC68HC908GT16 • MC68HC908GT8 — Rev. 2
Electrical Specifications
MOTOROLA