TMS3705

www.ti.com

11-07-22-003 – SCBS881B – JANUARY 2010 – REVISED APRIL 2010

TRANSPONDER BASE STATION IC

Check for Samples: TMS3705

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FEATURES

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Base Station IC for TI-RFid™ RF Identification

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Short-Circuit Protection

Systems

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Diagnosis

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Drives Antenna

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Sleep-Mode Supply Current: 0.2 mA

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Sends Modulated Data to Antenna

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Designed for Automotive Requirements

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Detects and Demodulates Transponder

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16-Pin SOIC (D) Package

Response (FSK)

DESCRIPTION

The transponder base station IC is used to drive the antenna of a TI-RFid™ transponder system, to send data

modulated on the antenna signal, and to detect and demodulate the response of the transponder. The response

of the transponder is a FSK signal (frequency shift keyed). The high or low bits are coded in two different

high-frequency signals (134.2 kHz for low bits and 123 kHz for high bits, nominal). The transponder induces

these signals in the antenna coil according an internally stored code. The energy the transponder needs to send

out the data is stored in a charge capacitor in the transponder. The antenna field charges this capacitor in a

preceding charge phase. The IC has an interface to an external microcontroller.

There are two configurations for the clock supply to both the microcontroller and the base station IC:

1. Microcontroller and base station IC are supplied with a clock signal derived from only one resonator: The

resonator is attached to the microcontroller. The base station IC is supplied with a clock signal driven by the

digital clock output of the microcontroller. The clock frequency is either 4 MHz or 2 MHz depending on the

selected microcontroller type.

2. Both the microcontroller and the base station have their own resonator.

The base station IC has a PLL on-chip that generates a clock frequency of 16 MHz for internal clock supply only.

The TMS3705BDRG4 is optimized for higher communication data rates and therefore works without frequency

measurement during the write phase.

ORDERABLE PART NUMBER

TOP-SIDE MARKING

TMS3705A1DRG4

TMS3705AG4

–40°C to 85°C

SOIC – D

Reel of 2500

TMS3705BDRG4

TMS3705BG4

(1)

For the most current package and ordering information, see the Package Option Addendum at the end of this document, or see the TI

web site at www.ti.com.

(2)

Package drawings, thermal data, and symbolization are available at www.ti.com/packaging.

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Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas

Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

PRODUCTION DATA information is current as of publication date.

Copyright © 2010, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.