S1M8836 Samsung Semiconductor, Inc., S1M8836 Datasheet - Page 21

• Manufacturer Part Number: S1M8836
• 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 buffer is powered down when the
power down bits (W4[20] and W1[20]) become 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.
There are synchronous and asynchronous power-down modes for S1M8836/37. The power-down bit W1[19] is
used to select between synchronous and asynchronous power-down. Synchronous power-down mode occurs if
W1[19] bit is HIGH and then the power down bit (W4[20] or W1[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 W1[19] bit is LOW and then the power down bit (W4[20] or W1[20])
becomes HIGH. Activation of the asynchronous function will go into power-down mode immediately.
RF Power down mode table
RF_CTL_WORD
IF_CTL_WORD
Control Words
W4[20]
0
0
1
1
Control bits
W1[20]
W1[19]
W4[20]
VCO
Output
Frequency
W1[19]
0
1
1
1
PWDN_RF
PWDN_IF
Acronym
PWDN
VCO Characteristics
VCO Input
RF PLL active
RF PLL active, only charge pump to TRISTATE
Asynchronous power down
Synchronous power down
Voltage
asynchronous
power down
power up
power up
LOW (0)
Power down mode status
(1)
(2)
synchronous power
power down
power down
HIGH (1)
down
Comments
RF and IF
S1M8836/37
RF
IF
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