ELANSC400-66AI AMD (ADVANCED MICRO DEVICES), ELANSC400-66AI Datasheet - Page 81

• Manufacturer Part Number: ELANSC400-66AI
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of ELANSC400-66AI

• Cpu Family: Elan
• Device Core Size: 16/32Bit
• Frequency (max): 66MHz
• Interface Type: ISA
• Program Memory Type: ROMLess
• Program Memory Size: Not Required
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 3V
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 95C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 292
• Package Type: BGA
• Lead Free Status / Rohs Status: Not Compliant

High-Speed PLL
The High-Speed PLL generates a 66.3552-MHz clock
for the DRAM controller. Figure 10 on page 82 shows
the block diagram for the High-Speed PLL. The input to
the High-Speed PLL is the output of the Low-Speed
PLL divided by five. The feedback divider is nine, which
results in an output frequency (Fo) of 66.3552 MHz.
This frequency is divided by 2 in the PMU to provide the
33-MHz input for the PLL in the CPU core.
Band Gap Block
The band gap reference circuit generates the bias cur-
rents for the four PLLs and provides a 2.4-V reference
source for the RTC voltage monitor. The current
sources, constant over V
variations, are used by the four PLL charge pumps for
adjusting the PLL operating frequency. The 2.4-V refer-
ence voltage is used by the RTC voltage monitor to de-
tect a low backup battery voltage level.
36.864 MHz
CC
Élan™SC400 and ÉlanSC410 Microcontrollers Data Sheet
, temperature, and process
/16
Figure 9. Graphics Dot Clock PLL Block Diagram
Ff
Fr
Programmable
PLLRATIO[2–0]
Divider
(9–16)
Detector
Phase
Down
36.864 MHz
20.736–
Up
Fo
RTC Voltage Monitor
The voltage monitor for the RTC block is shown in
Figure 11 on page 82. Its functions are to provide a
reset signal to the RTC block when it detects a low
backup battery voltage, and to provide an early warn-
ing signal when the system is powering down.
The internal RTC reset signal is asserted on power-up
if the back-up battery voltage drops below 2.4 V. The
one shot prevents multiple resets during power-on.
An internal power-down signal is used by the RTC to
i s o l a t e t h e R T C c o r e f r o m t h e r e s t o f t h e
microcontroller. The RTC voltage monitor uses the
RESET assertion to detect a power-down. For proper
operation, RESET and V
Figure 12 on page 83.
Charge
Pump
VCO
Internal
Vc
CC
External
Loop
must follow the timing in
VCCA
R
C
1
Filter
C
2
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