UMA1021M Datasheet, PDF (2/16 Pages) NXP Semiconductors – Low-voltage frequency synthesizer for radio telephones

Philips Semiconductors
Low-voltage frequency synthesizer
for radio telephones
Product specification
UMA1021M
FEATURES
• Low phase noise
• Low current from 3 V supply
• Fully programmable main divider
• 3-line serial interface bus
• Independent fully programmable reference divider,
driven from external crystal oscillator
• Dual charge pump outputs
• Hard and soft power-down control.
APPLICATIONS
• 900 MHz and 2 GHz mobile telephones
• Portable battery-powered radio equipment.
GENERAL DESCRIPTION
The UMA1021M BICMOS device integrates a prescaler,
programmable dividers, and a phase comparator to
implement a phase-locked loop.
The device is designed to operate from 3 NiCd cells, in
pocket phones, with low current and nominal 3 V supplies.
The synthesizer operates at RF input frequencies up to
2.2 GHz, with a fully programmable reference divider.
All divider ratios are supplied via a 3-wire serial
programming bus.
Separate power and ground pins are provided to the
analog (charge-pump) and digital circuits. The ground
leads should be externally short-circuited to prevent large
currents flowing across the die and thus causing damage.
V_DD1 and V_DD2 must also be at the same potential (V_DD).
V_CC must be equal to or greater than V_DD (e.g. V_DD = 3 V
and V_CC = 5 V for wider VCO control voltage range).
The phase detector has two charge-pump outputs, CP and
CPF, the latter of which is enabled directly at pin FAST.
This permits the design of adaptive loops. The charge
pump currents (phase detector gain) are fixed by an
external resistance at pin I_SET and via the serial interface.
Only a passive loop filter is necessary; the charge pumps
function within a wide voltage compliance range to
improve the overall system performance.
QUICK REFERENCE DATA
SYMBOL
PARAMETER
CONDITIONS
V_DD
V_CC
I_DD + I_CC
I_CC(pd) + I_DD(pd)
f_RF
f_xtal
f_PC
T_amb
digital supply voltage
charge-pump supply voltage
supply current
total supply current in power-down mode
RF input frequency
crystal reference input frequency
phase comparator frequency
operating ambient temperature
V_DD1 = V_DD2;
V_CC ≥ V_DD
V_CC ≥ V_DD
MIN. TYP. MAX. UNIT
2.7
−
5.5
V
2.7
−
5.5
V
−
10
−
mA
−
5
−
µA
300
−
2200 MHz
3
−
35
MHz
−
200
−
kHz
−30
−
+85
°C
ORDERING INFORMATION
TYPE
NUMBER
UMA1021M
PACKAGE
NAME
DESCRIPTION
SSOP20 plastic shrink small outline package; 20 leads; body width 4.4 mm
VERSION
SOT266-1
1999 Jun 17
2