IDT82V3285DQ IDT, Integrated Device Technology Inc, IDT82V3285DQ Datasheet - Page 20

• Manufacturer Part Number: IDT82V3285DQ
• Manufacturer: IDT, Integrated Device Technology Inc

Specifications of IDT82V3285DQ

• Function: Wan PLL
• Operating Temperature (max): 85C
• Operating Temperature (min): -40C
• Package Type: TQFP
• Pin Count: 100
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Not Compliant

Table 4: Related Bit / Register in Chapter 3.4
3.4
is used to divide the clock frequency down to the DPLL required fre-
quency, which is no more than 38.88 MHz.
ing IN_FREQ[3:0] bits.
bypassed automatically and the corresponding IN_FREQ[3:0] bits
should be set to match the input frequency; the input clock can be
inverted, as determined by the IN_2K_4K_8K_INV bit.
available for IN3 and IN4), a DivN Divider and a Lock 8k Divider, as
shown in
used when the input clock is higher than (>) 155.52 MHz. The input
clock can be divided by 4, 5 or can bypass the HF Divider, as deter-
mined by the IN3_DIV[1:0]/IN4_DIV[1:0] bits correspondingly.
can be bypassed, as determined by the DIRECT_DIV bit and the
LOCK_8K bit.
setting should observe the following order:
Functional Description
IDT82V3285
Each input clock is assigned an internal Pre-Divider. The Pre-Divider
For IN1 ~ IN5, the DPLL required frequency is set by the correspond-
If the input clock is of 2 kHz, 4 kHz or 8 kHz, the Pre-Divider is
Each Pre-Divider consists of a HF (High Frequency) Divider (only
The HF Divider, which is only available for IN3 and IN4, should be
Either the DivN Divider or the Lock 8k Divider can be used or both
When the DivN Divider is used for INn (1 ≤ n ≤ 5), the division factor
1. Select an input clock by the PRE_DIV_CH_VALUE[3:0] bits;
2. Write the lower eight bits of the division factor to the
3. Write the higher eight bits of the division factor to the
PRE_DIVN_VALUE[7:0] bits;
PRE_DIVN_VALUE[14:8] bits.
Figure
PRE_DIV_CH_VALUE[3:0]
PRE_DIVN_VALUE[14:0]
Input Clock INn
INPUT CLOCK PRE-DIVIDER
(1 ≤ n ≤ 5)
IN_2K_4K_8K_INV
IN_FREQ[3:0]
DIRECT_DIV
IN3_DIV[1:0]
IN4_DIV[1:0]
3.
LOCK_8K
Bit
Pre-Divider
(for IN3 & IN4 only)
HF Divider
IN3_DIV[1:0] bits / IN4_DIV[1:0] bits
Figure 3. Pre-Divider for An Input Clock
PRE_DIVN[14:8]_CNFG, PRE_DIVN[7:0]_CNFG
DivN Divider
IN3_IN4_HF_DIV_CNFG
IN1_CNFG ~ IN5_CNFG
IN1_CNFG ~ IN5_CNFG
20
FR_MFR_SYNC_CNFG
PRE_DIV_CH_CNFG
PRE_DIV_CH_VALUE[3:0] bits, it is valid until a different division factor
is set for the same input clock. The division factor is calculated as fol-
lows:
lower than (<) 155.52 MHz.
8 kHz automatically.
on the input clock on one of the IN1 ~ IN5 pins and the DPLL required
clock. Here is an example:
clock is 6.48 MHz by programming the IN_FREQ[3:0] bits of register IN4
to ‘0010’. Do the following step by step to divide the input clock:
DIRECT_DIV bit
Once the division factor is set for the input clock selected by the
The DivN Divider can only divide the input clock whose frequency is
When the Lock 8k Divider is used, the input clock is divided down to
The Pre-Divider configuration and the division factor setting depend
The input clock on the IN4 pin is 622.08 MHz; the DPLL required
Register
1. Use the HF Divider to divide the clock down to 155.52 MHz:
2. Use the DivN Divider to divide the clock down to 6.48 MHz:
Division Factor = (the frequency of the clock input to the DivN
Divider ÷ the frequency of the DPLL required clock set by the
IN_FREQ[3:0] bits) - 1
622.08 ÷ 155.52 = 4, so set the IN4_DIV[1:0] bits to ‘01’;
Set the PRE_DIV_CH_VALUE[3:0] bits to ‘0110’;
Set the DIRECT_DIV bit in Register IN4_CNFG to ‘1’ and the
LOCK_8K bit in Register IN4_CNFG to ‘0’;
155.52 ÷ 6.48 = 24; 24 - 1 = 23, so set the
PRE_DIVN_VALUE[14:0] bits to ‘10111’.
Lock 8k Divider
LOCK_8K bit
DPLL required clock
16 ~ 17, 19 ~ 1A, 1F
16 ~ 17, 19 ~ 1A, 1F
Address (Hex)
April 11, 2007
25, 24
18
74
23
WAN PLL