zl30100 Zarlink Semiconductor, zl30100 Datasheet - Page 24

• Manufacturer Part Number: zl30100
• Description: T1/e1 System Synchronizer
• Manufacturer: Zarlink Semiconductor

The crystal should be a fundamental mode type - not an overtone. The fundamental mode crystal permits a simpler
oscillator circuit with no additional filter components and is less likely to generate spurious responses. A typical
crystal oscillator specification and circuit is shown in Table 7 and Figure 14 respectively.
6.3
The ZL30100 requires that the 3.3 V rail is not powered-up later than the 1.8 V rail. This is to prevent the risk of
latch-up due to the presence of parasitic diodes in the IO pads.
Two options are given:
1. Power up the 3.3 V rail fully first, then power up the 1.8 V rail
2. Power up the 3.3 V rail and 1.8 V rail simultaneously, ensuring that the 3.3 V rail voltage is never lower than the
1.8 V rail voltage minus a few hundred millivolts (e.g., by using a schottky diode or controlled slew rate)
Power Up Sequence
1
2
3
4
5
6
ZL30100
Table 7 - Typical Crystal Oscillator Specification
Frequency
Tolerance
Oscillation mode
Resonance mode
Load capacitance
Maximum series resistance
The 100: resistor and the 1 µH inductor may improve
stability and are optional.
Figure 14 - Crystal Oscillator Circuit
OSCi
OSCo
1 M:
Zarlink Semiconductor Inc.
ZL30100
100 :
24
20 MHz
20 MHz
as required
fundamental
parallel
as required
50
:
1 µH
Data Sheet