器件名称: U2895B
功能描述: Modulation PLL for GSM, DCS and PCS Systems
文件大小: 803.5KB 共16页
简 介: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 modulator, 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 transmitter architecture at which the VCO operates at the TX output frequency. No duplexer is needed since the out-ofband 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 D D D D D
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
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 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 PF……
