STC3500 Datasheet, PDF (47/48 Pages) Connor-Winfield Corporation – INTEGRATED - STRATUM 3 TIMING SOURCE

Mechanical Specifications continued
Additional External Components
1. Place series resistors (33 ohms) on all reference inputs.
2. Place series resistors (33 ohms) on SPI_IN and SPI_CLK inputs.
3. Place one .01uF at the input power pins.
4. One 4.7uF (25V) capacitor is required at the VPP pin.
5. One 4.7uF (25V) capacitor is required at the VPN pin.
PCB Layout Recommendations
1. Place .01 nF caps close to Vcc pins.
2. Place de-coupling and/or filter components as close to module pins as possible.
3. Ensure that only clean and well-regulated power is supplied to the module.
4. Isolate power and ground inputs to the module from noisy sources.
5. Must provide a separate power and ground trace to the oscillator that provides sufficient power to the oscillator.
6. Keep module signals away from sensitive or noisy analog and digital circuitry.
7. Avoid split ground planes as high-frequency return currents may be affected.
8. Allow extra spacing between traces of high-frequency inputs and outputs.
9. Keep all traces as short as possible - avoid meandering trace paths.
10. It is recommended that the connections of the JTAG, VPP and VPN pins be routed to pads, preferably in a SIL
pattern as shown in Figure 15 below. It is recommended to use 0.1” center to center spacing.
JTAG/ISP Header Connections
Figure 15
1
8
Preliminary Data Sheet: TM060 Page 47 of 48 Rev: P06 Date: 11/22/04
© Copyright 2001 The Connor-Winfield Corp. All Rights Reserved Specifications subject to change without notice