UAA3535HL

General description

The UAA3535HL is intended for Global Systems for Mobile communication (GSM), Digital Cellular communication Systems (DCS) and Personal Communication Services (PCS). The circuit integrates the receiver and most of the transmitter section of hand-held transceivers for these applications.

The receiver consists of two sections. The first section is the RF receiver front-end, which amplifies the GSM, DCS or PCS aerial signal, then converts the chosen channel down to a low Intermediate Frequency (IF) of 100 kHz, and also provides more than 35 dB image suppression. Some selectivity is provided at this stage by an on-chip low-pass filter and channel selectivity is provided by a high performance integrated band-pass filter.

The second section is the IF section, which further amplifies the chosen channel and performs gain control to adjust the output level to the desired value. The IF gain can be varied over more than 64 dB gain range.

The transmitter also consists of two sections. The first is a high precision I/Q modulator which converts the baseband modulation up to the transmit IF. The second is a modulation loop architecture which converts the signal to RF.

The Local Oscillator (LO) signals are provided by an on-chip Voltage Controlled Oscillator (VCO) for operation of the IF section and are provided externally for operation of the RF section. The frequencies of the RF and IF VCOs are set by internal PLL circuits, which are programmable via a 3-wire serial bus. Comparison frequencies are 200 kHz (100 kHz step programmability) and 13 MHz for the RF and IF PLL respectively, and are derived from a 13 MHz reference signal which has to be supplied externally. The quadrature-phase RF LO signals required for I/Q mixers in reception are generated internally. The quadrature LO signals required for operation of the I/Q modulator are generated inside the IF VCO.

The circuit can be powered-up into one of three different modes: RX, TX or SYN mode, depending on the logic state of pins RXON, TXON and SYNON, respectively. It is also possible to set the IC in one of these modes by software, using the 3-wire bus serial programming. In RX (TX) mode, all sections required for receive (transmit) are turned on. The SYN mode is used to power-up the synthesizers prior to the RX or TX mode. In the SYN mode, some internal LO buffers are also powered-up in such a way that VCO pulling is minimized when switching on the receiver or the transmitter. Additional band selection is done using the 3-wire bus serial programming, allowing the required enabling of the Low Noise Amplifiers (LNAs) and charge pumps current programming.

Features

• Multi-band application for GSM, DCS and PCS cellular phone systems
• Low noise and wide dynamic range low IF receiver
• More than 35 dB on-chip image rejection in receive mode
• More than 64 dB gain control range in receive mode
• Integrated channel filter
• Integrated TX low-pass filter
• High precision I/Q modulator
• Multi-band TX modulation loop architecture including offset mixer and phase-frequency detector
• Dual PLL with on-chip fully integrated IF VCO
• Fully differential design minimizing crosstalk and spurious signals
• Functional down to 2.4 V and up to 3.6 V
• 3-wire serial bus interface
• LQFP48 package.

Applications

• GSM 900 MHz, DCS 1800 MHz and PCS 1900 MHz hand-held transceivers.

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Disclaimers

• General product disclaimer
• Quality and reliability disclaimer