U2731B-NFNG1
| Model | U2731B-NFNG1 |
| Description | DAB ONE- CHIP FRONT END |
| PDF file | Total 25 pages (File size: 654K) |
| Chip Manufacturer | ATMEL |
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8.5 V Supply Voltage
Voltage Regulator for Stable Operating Conditions
Microprocessor-controlled Via a Simple Two-wire Bus
Two Addresses Selectable
Gain-controlled RF Amplifier with Two Inputs, Selectable Via a Simple Two-wire Bus
Control
Balanced RF Amplifier Inputs
Gain-controlled RF Mixer
Four-pin Voltage-controlled Oscillator
SAW Filter Driver with Differential Low-impedance Output
AGC Voltage Generation for RF Section, Available at Charge-pump Output
(Can Also Be Used to Control a PIN Diode Attenuator)
Gain-controlled IF Amplifier
Balanced IF Amplifier Inputs
Selectable Gain-controlled IF Mixer
Single-ended IF Output
AGC Voltage Generation for IF Section, Available at Charge-pump Output
Separate Differential Input for the IF AGC Block
All AGC Time Constants Adjustable
AGC Thresholds Programmable Via a Simple Two-wire Bus
Three AGC Charge Pump Currents Selectable (Zero, Low, High)
Reference Oscillator
Programmable 9-bit Reference Divider
Programmable 15-bit Counter 1:2048 to 1:32767 Effectively
Tristate Phase Detector with Programmable Charge Pump
Superior Phase-noise Performance
Deactivation of Tuning Output Programmable
Three Switching Outputs (Open Collector)
Three D/A Converters (Resolution: 8 Bits)
Lock Status Indication (Open Collector)
DAB One-chip
Front End
U2731B
Electrostatic sensitive device.
Observe precautions for handling.
Description
The U2731B is a monolithically integrated Digital Audio Broadcasting one-chip front
end circuit manufactured using Atmel’s advanced UHF5S technology. Its functionality
covers a gain-controlled RF amplifier with two selectable RF inputs, a gain-controlled
RF mixer, a VCO which provides the LO signal for the RF mixers, either directly or
after passing a frequency divider, a SAW filter driver, an AGC block for the RF section,
a gain-controlled IF amplifier, an IF mixer which can also be bypassed, an AGC block
for the IF section and a fractional-N frequency synthesizer. The frequency synthesizer
controls the VCO to synthesize frequencies in the range of 70 MHz to 500 MHz in a
16-kHz raster; within certain limits the reference divider factor is fully programmable.
The lock status of the phase detector is indicated at a special output pin; three switch-
ing outputs can be addressed. A reference signal which is generated by an on-chip
reference oscillator is available at an output pin. This reference signal is also used to
generate the LO signal for the IF mixer, either by doubling the frequency or by using
the reference frequency itself. Three D/A converters at a resolution of 8 bits provide a
digitally controllable output voltage. The thresholds inside the AGC blocks can be digi-
tally controlled by means of on-chip 4-bit D/A converters. All functions of this IC are
controlled via a simple two-wire bus.
Rev. 4671C–DAB–06/04
