U2895B
| Model | U2895B |
| Description | Modulation PLL for GSM, DCS and PCS Systems |
| PDF file | Total 16 pages (File size: 805K) |
| Chip Manufacturer | ETC |
U2895B
Modulation PLL for GSM, DCS and PCS Systems
Description
The U2895B 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 U2895B is designed for cellular phones such as
GSM900, DCS1800, and PCS1900, applying a trans-
mitter 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 U2895B exhibits low power
consumption. Broadband operation gives high flexibility
for multi-band frequency mappings. The IC is available
in a shrinked small-outline 28-pin package (SSO28).
Electrostatic sensitive device.
Observe precautions for handling.
Features
D
D
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D
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Supply voltage range 2.7 V to 5.5 V
Current consumption 50 mA
Power-down functions
High-speed PFD and charge pump (CP)
Small CP saturation voltages (0.5/0.6 V)
Programmable dividers and CP polarity
Low-current standby mode
Benefits
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Novel TX architecture saves filter costs
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Extended battery operating time without duplexer
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Less board space (few external components)
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VCO control without voltage doubler
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Small SSO28 package
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One device for all GSM bands
Block Diagram
I NI
1
2
MDLO Q NQ PUMIX PU MIXO MIXLO
3
28 27
12
19
25
20
22
23
MDO
NMDO
5
6
+
90°
2
Voltage
reference
Mixer
RF
NRF
I/Q modulator
16
17
13
14
R 1
divider
N 1
divider
MUX
PFD
Charge
pump
9
8
VSP
ND
NND
RD
NRD
CPO
7
21
VS1
VS2
VS3
MC
15
Mode
control
4
18
24
11
CPC
10
GNDP
GND
Figure 1. Block diagram
26
15048
Rev. A3, 30-Sep-98
1 (16)
