20-668-0024 Rabbit Semiconductor, 20-668-0024 Datasheet - Page 325

• Manufacturer Part Number: 20-668-0024
• Description: IC CPU RABBIT4000 128-LQFP
• Manufacturer: Rabbit Semiconductor

Specifications of 20-668-0024

• Processor Type: Rabbit 4000 8-bit
• Speed: 60MHz
• Voltage: 2.5V, 2.7V, 3V, 3.3V
• Mounting Type: Surface Mount
• Package / Case: 128-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Features: -
• Other names: 20-668-0022; 316-1078

When the doubler is used, the duty cycle of the clock becomes a critical parameter. The
duty cycle should be measured at the separate clock output pin (pin 2). The minimum
period must be increased by any amount that the clock high time is greater or less than
specified in the duty-cycle requirement.
For example, consider a design where the spreader and doubler are enabled, with 8 ns
nominal delay in the doubler. The high and low clock are equal to within 1 ns. This violates the
duty cycle requirement by 3 ns since (clock low - clock high) can be as small as -1 ns, but
the requirement is that it not be less than 2 ns. Thus, 3 ns must be added to the minimum
period of 21 ns, giving a minimum period of 24 ns and a maximum frequency of 41.6 MHz
(commercial).
Chapter 28 Specifications
No Doubler or
Spreader
Spreader Only
Normal
Spreader Only
Strong
Doubler Only
(8 ns delay)
Doubler Only
(internal 50%
clock)
Spreader
Normal with
Doubler
(8 ns delay)
Spreader
Normal with
Doubler (8 ns
delay), Internal
50% Clock
Spreader Only
Strong
Spreader Strong
with Doubler
(8 ns delay)
Conditions
Table 28-11. Preliminary Maximum Clock Speeds
(V
DD
Minimum
±10%, Temp. -40°C to +85°C)
Period
Industrial Ratings
(ns)
21.5
17
20
21
19
20
21
24
23
Frequency
Maximum
(MHz)
58.8
50.0
47.6
52.6
47.6
41.6
46.5
43.5
50
1 > (clock low -
clock high) > 0
1 > (clock low -
clock high) > -1
4 > (clock low -
clock high) > 2
1 > (clock low -
clock high) > -1
8 > (clock low -
clock high) > 6
Requirements
Duty Cycle
(ns)
315