lmx2322 National Semiconductor Corporation, lmx2322 Datasheet - Page 11

• Manufacturer Part Number: lmx2322
• Description: Pllatinumtm 2.0 Ghz Frequency Synthesizer For Rf Personal Communications
• Manufacturer: National Semiconductor Corporation

LMX2322
2.3.4 CTL_WORD
MSB
2.3.4.1 Reserve Word Truth Table
Notes:
X denotes don’t care.
1. The Counter Reset bit when activated allows the reset of both N and R counters. Upon powering up the N counter
2. Both synchronous and asynchronous power down modes are available with the LMX2322 to be able to adapt to
different types of applications. The MICROWIRE control register remains active and capable of loading and latching in
data during all of the powerdown modes
Synchronous Power down Mode
Asynchronous Power down Mode
Rev 1.6
CNT_RST
The PLL loops can be synchronously powered down by setting the counter reset mode bit to LOW (N[2] = 0)
and its power down mode bit to HIGH (N[1] = 1). The power down function is gated by the charge pump. Once
the power down mode and counter reset mode bits are loaded, the part will go into power down mode upon the
completion of a charge pump pulse event.
The PLL loops can be asynchronously powered down by setting the counter reset mode bit to HIGH (N[2] = 1)
and its power down mode bit to HIGH(N[1] = 1). The power down function is NOT gated by the charge pump.
Once the power down and counter reset mode bits are loaded, the part will go into power down mode
immediately.
The R and N counters are disabled and held at load point during the synchronous and asynchronous power
down modes. This will allow a smooth acquisition of the RF signal when the PLL is programmed to power up.
Upon powering up, both R and N counters will start at the ‘zero’ state, and the relationship between R and N will
not be random.
resumes counting in "close" alignment with the R counter. (The maximum error is one prescalar cycle).
CE
1
1
1
1
0
PWDN
CNT_RST
X
0
0
1
1
LSB
PWDN
0
1
0
X
1
9/24/1998
Normal Operation
Synchronous Powerdown
counter reset
Asynchronous Powerdown
Asynchronous Powerdown
FUNCTION
Advance Information
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