U2894B Datasheet, PDF (1/16 Pages) TEMIC Semiconductors – Modulation PLL for GSM, DCS and PCS Systems

U2894B
Modulation PLL for GSM, DCS and PCS Systems
Description
The U2894B is a monolithic integrated circuit. It is
realized using TEMIC’s advanced silicon bipolar UHF5S
technology. The device integrates a mixer, an I/Q modu-
lator, a phase-frequency detector (PFD) with two
synchronous programmable dividers, and a charge pump.
The U2894B is designed for cellular phones such as
GSM900, DCS1800, and PCS1900, applying a
transmitter architecture at which the VCO operates at the
TX output frequency. No duplexer is needed since the out-
of-band noise is very low. The U2894B exhibits low
power consumption. Broadband operation gives you high
flexibility for multi-band frequency mappings. The IC is
available in a shrinked small-outline 28-pin package
(SSO28).
The U2893B offers the same functionality with other
divider ratios.
Electrostatic sensitive device.
Observe precautions for handling.
Features
D Supply voltage range 2.7 V to 5.5 V
D Current consumption 50 mA
D Power-down functions
D High-speed PFD and charge pump (CP)
D Small CP saturation voltages (0.5/0.6 V)
D Programmable dividers and CP polarity
D Low-current standby mode
Benefits
D Novel TX architecture saves filter costs
D Extended battery operating time without duplexer
D Less board space (few external components)
D VCO control without voltage doubler
D Small SSO28 package
D One device for all GSM bands
Block Diagram
I NI
12
MDLO Q NQ PUMIX PU MIXO MIXLO
3 28 27 12 19 25 20
5
MDO
6
NMDO
90°
+
I/Q modulator
16
ND
17
NND
N1
divider
13
RD
14
NRD
R1
divider
MUX
Voltage
reference
PFD
15
MC
Mode
control
4 18 24
GND
Figure 1. Block diagram
Mixer
22
RF
NRF
23
8
VSP
Charge
pump
9
CPO
11
CPC
7
VS1
21
VS2
26
VS3
10
GNDP
12494
Rev. A4, 30-Sep-98
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