Zilog Z16C35 - Manual (Page 309)

On-Chip Oscillator Design
15-9
1
SUMMARY
Understanding the Theory of Operation of oscillators,
combined with practical applications, should give
designers enough information to design reliable oscillator
circuits. Proper selection of crystals and load capacitors, along with good layout practices, results in a cost effective,
trouble free design.Reference the following text for Zilog
products with on-chip oscillators and their general/
specific requirements.
ZILOG PRODUCT USING ON-CHIP OSCILLATORS
Zilog products that have on-chip oscillators:
Z8
®
Family: All
Z80
®
: C01, C11, C13, C15, C50, C90, 180, 181, 280
Z8000
®
: 8581
Communications Products: SCC
™
, ISCC
™
, ESCC
™
ZILOG CHIP PARAMETERS
The following are some recommendations on
values/parameters of components for use with Zilog on-
chip oscillators. These are only recommendations; no
guarantees are made by performance of components
outside of Zilog ICs. Finally, the values/parameters chosen
depend on the application. This App Note is meant as a
guideline to making these decisions. Selection of optimal
components is always a function of desired
cost/performance tradeoffs.
Note: All load capacitance specs include stray
capacitance.
Z8 Family
General Requirements:
Crystal Cut: AT cut, parallel resonant, fundamental mode
Crystal Co: < 7 pF for all frequencies.
Crystal Rs: < 100 ohms for all frequencies.
Load Capacitance: 10 to 22 pf, 15 pF typical.
Specific Requirements:
8604: xtal or ceramic, f = 1 - 8 MHz.
8600/10: f = 8 MHz.
8601/03/11/13: f = 12.5 MHz.
8602: xtal or ceramic, f = 4 MHz.
8680/81/82/84/91: f = 8, 12, 16, MHz.
8671: f = 8 MHz.
8612: f = 12, 16 MHz.
86C08/E08: f = 8, 12 MHz.
86C09/19: xtal/resonator, f = 8 MHz, C = 47 pf max.
86C00/10/20/30: f = 8, 12, 16 MHz
86C11/21/91/40/90: f = 12, 16, 20 MHz.
86C27/97: f = 4, 8 MHz.
86C12: f = 12, 16 MHz.
Super8 (all): f = 1 - 20 MHz.
Z8000 Family (8581 only)
General Requirements:
Crystal cut: AT cut, parallel resonant, fundamental mode.
Crystal Co: < 7 pF for all frequencies.
Crystal Rs: < 150 ohms for all frequencies.
Load capacitance: 10 to 33 pF.
Z80 Family
General Requirements:
Crystal cut: AT cut, parallel resonant, fundamental mode.
Crystal Co: < 7 pF for all frequencies.
Crystal Rs: < 60 ohms for all frequencies.
Load capacitance: 10 to 22 pF.
Specific Requirements:
84C01: C1 = 22 pF, C2 = 33 pF (typ); f = DC to 10 MHz.
84C90: DC to 8 MHz.
84C50: same as 84C01.
84C11/13/15: C1 = C2 = 20 -33 pf; f = 6 -10 MHz
80180: f = 12, 16, 20 MHz (Fxtal = 2 x sys. clock).
80280: f = 20 MHz (Fxtal = 2 x Fsysclk).
80181: TBD.
Communications Family
General Requirements:
Crystal cut: AT cut, parallel resonant, fundamental mode.
Crystal Co: < 7 pF for all frequencies.
Crystal Rs: < 150 ohms for all frequencies.
Load capacitance: 20 to 33 pF.
Frequency: cannot exceed PCLK.
Specific Requirements:
8530/85C30/SCC: f = 1 - 6 MHz (10 MHz SCC), 1 - 8.5
MHz (8 MHz SCC).
85130/ESCC (16/20 MHz), f = 1 - 16.384 MHz.
16C35/ISCC: f = 1 -10 MHz.
Application Note
Page 303 of 316
UM011002-0808