1999 Jun 17

2

Philips Semiconductors

Product specification

Low-voltage frequency synthesizer

for radio telephones

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.

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

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

ORDERING INFORMATION

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

digital supply voltage

2.7

−

5.5

V

charge-pump supply voltage

2.7

−

5.5

V

supply current

−

10

−

mA

−

5

−µA

RF input frequency

300

−

2200

MHz

crystal reference input frequency

3

−

35

MHz

phase comparator frequency

−

200

−

kHz

operating ambient temperature

−30

−

+85

°C

TYPE

NUMBER

PACKAGE

NAME

DESCRIPTION

VERSION

UMA1021M

SSOP20

plastic shrink small outline package; 20 leads; body width 4.4 mm

SOT266-1