1.25-GHz PLL with Prescaler
2.5-GHz PLL with Prescaler
PMB 2308
B6HF
PMB 2309
B6HF
General Description
The PMB 2308, PMB 2309 are Phase Locked Loop (PLL)
synthesizers with programmable frequency dividers for use
in mobile communication equipment. It is fabricated using
Siemens B6HF silicon bipolar process.
The circuit consists of high speed dual modulus divider, shift
register, programmable counter (A-, N- and R-counter),
phase detector with charge pump and a control logic block.
Since the high speed dual modulus divider is able to handle
frequencies of up to 1.25 (2.5) GHz, there is no need to add
a dedicated external prescaler. The switching signals for the
dividing ratio 16/17 (32/33) is generated by the A-counter.
The A-counter and the N-down-counter are programmable
via the 3-wire bus. They are clocked by the dual modulus
divider output signal. The carry output of the N-counter is
connected to the frequency input of the phase detector and
is controlling the loading of the programmed A-/N-counter
start values.
The 11 bit R-counter is also programmable and is serving as
reference frequency divider. Its carry output is connected to
the reference frequency input of the phase detector and is
controlling the loading of the programmed counter start
value.
The phase detector is of PFD-type (phase and frequency
sensitive). It has a linear output characteristic in the 0˚ phase
error region.
The control logic handles phase detector output polarity,
charge pump output current and software-generated power-
down (all circuit parts except the shift registers and data
latches).
Applications
All mobile communication analog and digital systems as RF-
and IF synthesizers
Type
PMB 2308-R
PMB 2309-R
Features
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Package
P-TSSOP-16-1 (Shrink, SMD)
P-TSSOP-16-1 (Shrink, SMD)
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Integrated prescaler
Low operating current
Different power-down modes
High input sensitivity, high input frequency
Fast phase detector without dead zone
Linearization of the phase detector output by current
sources
Large dividing ratios for small channel spacing
PLL
PMB 2308
PMB 2309
max. freq.
1.25 GHz
2.5 GHz
prescaler:
:16/:17
:32/:33
A-counter
0 to 15
0 to 31
N-counter
16 to 4095
32 to 2047
R-counter
3 to 2047
3 to 2047
Serial control (3-wire bus: data, clock, enable) for fast
programming (
f
max
= 10 MHz)
Switchable polarity and phase detector current
programmable
1 port output (TTL push-pull)
External current setting for phase detector output
Lock detect output with gated pulse (quasi-digital lock
detect)
Operating voltage 2.7 V to 5.5 V
P-TSSOP-16 package
Temperature range – 30
°C
to 85
°C
Siemens Aktiengesellschaft
1
Embedded System
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