UMA1018M Datasheet, PDF (2/20 Pages) NXP Semiconductors – Low-voltage dual frequency synthesizer for radio telephones

Philips Semiconductors
Low-voltage dual frequency
synthesizer for radio telephones
Product specification
UMA1018M
FEATURES
• Low current from 3 V supply
• Fully programmable RF divider
• 3-line serial interface bus
• Second synthesizer to control first IF or offset loop
frequency
• Independent fully programmable reference dividers for
each loop, driven from external crystal oscillator
• Dual phase detector outputs to allow fast frequency
switching
• Integrated digital-to-analog converter
• Dual power-down modes.
APPLICATIONS
• 900 MHz mobile telephones
• Portable battery-powered radio equipment.
GENERAL DESCRIPTION
The UMA1018M BICMOS device integrates prescalers,
programmable dividers, and phase comparators to
implement two phase-locked loops. The device is
designed to operate from 3 NiCd cells, in pocket phones,
with low current and nominal 5 V supplies.
The principal synthesizer operates at RF input frequencies
up to1.25 GHz the auxiliary synthesizer operates at
300 MHz. The auxiliary loop is intended for the first IF or to
transmit offset loop-frequency settings. Each synthesizer
has 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 and digital circuits. The ground leads should be
externally short-circuited to prevent large currents flowing
across the die and thus causing damage. Digital supplies
V_DD1 and V_DD2 must also be at the same potential. V_CC
must be equal to or greater than V_DD (i.e. V_DD = 3 V and
V_CC = 5 V for wider tuning range).
The principal synthesizer phase detector uses two charge
pumps, one provides normal loop feedback, while the
other is only active during fast mode to speed-up
switching. The auxiliary loop has a separate phase
detector. All charge pump currents (gain) are fixed by an
external resistance at pin I_SET (pin 14). Only passive loop
filters are used; the charge-pumps function within a wide
voltage compliance range to improve the overall system
performance. An on-chip 7-bit DAC enables adjustment of
an external function, such as the temperature
compensation of a crystal oscillator in Global System for
Mobile communications (GSM).
QUICK REFERENCE DATA
SYMBOL
PARAMETER
CONDITIONS
V_CC, V_DD
I_CC + I_DD
supply voltage
principal synthesizer supply current
V_CC ≥ V_DD
auxiliary synthesizer in
power-down mode
principal and auxiliary synthesizer
supply current
principal and auxiliary
synthesizers ON
I_CCPD, I_DDPD
f_VCO
f_AI
f_XTAL
f_PPC
f_APC
T_amb
current in power-down mode per supply
principal input frequency
auxiliary input frequency
crystal reference input frequency
principal phase comparator frequency
auxiliary phase comparator frequency
operating ambient temperature
MIN.
2.7
−
TYP.
−
7.7
MAX.
5.5
−
UNIT
V
mA
−
10
−
mA
−
12
−
µA
50
−
1250 MHz
20
−
300 MHz
3
−
40
MHz
−
200 −
kHz
−
200 −
kHz
−30 −
+85 °C
1995 Jun 27
2