Information as of 2000-01-10
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UAA2077CM; 2 GHz image rejecting front-end

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Description

UAA2077CM contains both a receiver front-end and a high frequency transmit mixer intended to be used in mobile telephones. Designed in an advanced BiCMOS process it combines high performance with low power consumption and a high degree of integration, thus reducing external component costs and total front-end size.

The main advantage of the UAA2077CM is its ability to provide over 30 dB of image rejection. Consequently, the image filter between the LNA and the mixer is suppressed.

Image rejection is achieved in the internal architecture by two RF mixers in quadrature and two all-pass filters in I and Q IF channels that phase shift the IF by 45° and 135° respectively. The two phase shifted IFs are recombined and buffered to furnish the IF output signal.

Signals presented at the RF input at LO + IF frequency are rejected through this signal processing while signals at LO - IF frequency can form the IF signal.

The receiver section consists of a low-noise amplifier that drives a quadrature mixer pair. The IF amplifier has on-chip 45° and 135° phase shifting and a combining network for image rejection. The IF driver has differential open-collector type outputs.

The LO part consists of an internal all-pass type phase shifter to provide quadrature LO signals to the receive mixers. The all-pass filters outputs are buffered before being fed to the receive mixers.

The transmit section consists of a low-noise amplifier, and a down-conversion mixer. In the transmit mode, an internal LO buffer is used to drive the transmit IF down-conversion mixer.

All RF and IF inputs or outputs are balanced.

Pins RXON, TXON and SXON allow to control the different power-down modes. A synthesizer-on (SX) mode enables LO buffers independent of the other circuits. When pin SXON is HIGH, all internal buffers on the LO path of the circuit are turned on, thus minimizing LO pulling when remainder of the receive or transmit chain is powered up. Special care has been taken for fast power-up switching.

Features

• Low-noise, wide dynamic range amplifier
• Very low noise figure
• Dual balanced mixer for over 30 dB on-chip image rejection
• IF I/Q combiner at 188 MHz
• On-chip quadrature network
• Down-conversion mixer for closed-loop transmitters
• Independent TX/RX fast ON/OFF power-down modes
• Very small outline packaging
• Very small application (no image filter).

Applications

• High frequency front-end for DCS1800/PCS1900 hand-portable equipment
• Compact digital mobile communication equipment
• TDMA receivers e.g. RF-LANS.

Datasheet

Type nr.	Title	Publication release date	Datasheet status	Page count	File size (kB)	Datasheet
UAA2077CM	2 GHz image rejecting front-end	24-Sep-97	Product Specification	20	129	Open

Blockdiagram

Products, packages, availability and ordering

Partnumber	Order code (12nc)	marking/packing	package	device status	buy online
UAA2077CM/C1	9352 206 10112	Standard marking * tube	SOT266	RFS	-
	9352 206 10118	Standard marking * reel pack, SMD, 13"	SOT266	RFS	-
	9352 206 10512	Standard marking * tube dry pack	SOT266	WIT	-
	9352 206 10518	Standard marking * reel dry pack, SMD, 13"	SOT266	WIT	-

Please note, devices listed in the "Products, packages, availability and ordering" table marked with "WIT" are discontinued. Devices marked with "DOD" will be in the near future.
Contact your nearest sales or distributor office for the latest information on product status and availability.

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