Datasheet ML2721, ML2751 Datasheet (Micro Linear Corporation)

BRIEF

product

900MHz DSSS RF to Digital

All the BOM Advantages of Direct Conversion Radio

The Performance Advantages of a Superhet Radio

Small, Simple to Use and Ideal for Volume Manufacture

Transceiver Chipset

ML2721

Low IF Digital Cordless
Transceiver

ML2751

Features

ML2721

Fully Integrated Receiver With 900mhz RF In

And NRZ Out

Fully Integrated Transmitter With Integrated

Modulation Filter

Fully Integrated, Self Aligning IF Filtering,

Frequency To Voltage Converter, Transmit And
Receive Data Filters

Integrated Frequency Synthesizer With On

Chip Pre Aligned VCO

• Transmitter Low Voltage Lock-Out Circuit To Avoid

Out Of Band Emissions At Low Battery Voltage

• On-Chip DC Regulation For 2.7V To 5.0V Operation

• Analog RSSI Output

• Small 32 Pin TQFP Package, 0.75mm Pitch

Power Amplifier and LNA

ML2751

Power Amplifier Output +21dbm (125mw) Typical

Max Output At 3.0V
Power Amplifier Gain 35db (Typical Max)
Single Supply 2.7V - 4.5V Operating Range

Power Amplifier Efficiency 35% At 3.3V
PA Control Pin For Power Consumption Reduction In

Portable Products

On-Chip Low Noise Amplifier For Receiver
On-Chip PIN Diode Drivers For Tx/Rx
Small TSSOP-20 Package

900MHz DSSS RF to Digital Transceiver Chipset

Micro Linear has developed a single IC radio, the ML2721. The very high level of integration
absorbs all the circuits either difficult to design or those that require production alignment. Adding
just an external RF switch makes a complete radio with a digital control interface. On receive, the
input is RF, the output is demodulated data. All the LO circuits are integrated, including the VCO
tank circuit which Micro Linear tunes in production. For transmit, the chip is digital data in and
modulated RF out. To ensure proper functionality in products, all the DC regulation and power
management functions are integrated into the ML2721. This chip can be used for 900MHz ISM
band applications, as either a 1.1Mbps to 1.6Mbps FSK radio, or a 1.1Mcps direct sequence radio.
To extend the radio range, the ML2751 integrates a 100mW PA and a 18dB gain LNA. The ML2751
PA/LNA can implement front-end solutions for many communications products using TDD/TDMA
(half duplex radios) in the 600MHz to 1 GHz range and for transmitter powers up to 100mW at 3.0V.

Block Diagram

ANTENNA

RF PIN

DIODE

SWITCH

ML2751

LNA

PIN DIODE

DRIVERS

PA & DRIVER

902 - 928

MHz FILTER

ML2731

Tx RF

BUFFER

QUADRATURE

DIVIDED BY 2

IF CIRCUITS

VTUNE

FILTER
ALIGN

PLL

CONTROL

LOOP

FILTER

LOGIC

Tx DATA

FILTER

BASEBAND

IC

MODEM

CODEC

PROTOCOL

MMI

CONTROL

MEMORY

BATTERY

WATCH

AND

OSCILLATOR

XTAL

KEYPAD

DISPLAY

MIC

SPEAKER

RINGER

Micro Linear makes no representations or warranties with respect to the accuracy, utility, or completeness of the contents of this publication and reserves the right to make changes to specifications and product
descriptions at any time without notice. No license, express or implied, by estoppel or otherwise, to any patents or other intellectual property rights is granted by this document. The circuits contained in this
document are offered as possible applications only. Particular uses or applications may invalidate some of the specifications and/or product descriptions contained herein. The customer is urged to perform its
own engineering review before deciding on a particular application. Micro Linear assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale and/or use of Micro Linear
products including liability or warranties relating to merchantability, fitness for a particular purpose, or infringement of any intellectual property right. Micro Linear products are not designed for use in medical,

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10k 0200 PB2721-01