S1M8831A Samsung Semiconductor, Inc., S1M8831A Datasheet - Page 23

• Manufacturer Part Number: S1M8831A
• Description: Fractional-n Rf/integer-n If Dual Pll Frequency Synthesizer
• Manufacturer: Samsung Semiconductor, Inc.

FRACTIONAL-N RF/INTEGER-N IF DUAL PLL
Program Mode Control
Power Down Mode Operation
Each PLL is individually power controlled by the enable pins (RF_EN and IF_EN pins) or program control bits
(PWDN, PWDN_RF/IF). The enable pins override the program control bits. When both enable pins are HIGH, the
program control bits determine the state of power control. Power down forces all the internal analog blocks to be
deactivated and the charge pump output to be in a TRISTATE. The oscillator circuitry function becomes disabled
dependent on the state of IF and RF power-down bits, IF_N[20] and RF_N[22]. The RF(or IF) oscillator buffer is
powered down when the power down bit (RF_N[22] or IF_N[20]) becomes HIGH. The control register and R/N
counters, however, remains active for permitting serial programming and is capable of loading and latching in
data during the power down. The PLL returns to the active power-up mode when IF_N[20] and RF_N[22] become
LOW.
There are synchronous and asynchronous power-down modes for S1M8831A/33. The power-down bit IF_N[19] is
used to select between synchronous and asynchronous power down. Synchronous power down mode occurs if
IF_N[19] bit is HIGH and then the power down bit (RF_N[22] or IF_N[20]) becomes HIGH. In the synchronous
power down mode, the power-down function will go into power down mode upon the completion of a charge
pump pulse event because it is synchronized with the charge pump and thus can diminish undesired frequency
jumps. Asynchronous power down mode occurs if IF_N[19] bit is LOW and then the power down bit (RF_N[22] or
IF_N[20]) becomes HIGH. Activation of the asynchronous function will go into power-down mode immediately.
RF Power Down Mode Table
IF Power Down Mode Table
RF_CTL_WORD
IF_CTL_WORD
Control Words
RF_N[22]
IF_N[20]
0
0
1
1
0
0
1
1
Control bits
RF_N[22]
IF_N[20]
IF_N[19]
IF_N[19]
IF_N[19]
0
1
0
1
0
1
0
1
PWDN_RF
PWDN_IF
Acronym
PWDN
RF PLL active
RF PLL active, only charge pump to TRISTATE
Asynchronous power down
Synchronous power down
IF PLL active
IF PLL active, only charge pump to TRISTATE
Asynchronous power down
Synchronous power down
Asynchronous
Power Down
Power Up
Power Up
LOW (0)
Power Down Mode Status
Power Down Mode Status
Synchronous
Power Down
Power Down
Power Down
HIGH (1)
Comments
RF and IF
S1M8831A/33
RF
IF
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