LF Reader IC - TMS3705

TMS3705 (ACTIVE)

LF Reader IC

Description

The TMS3705 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 frequency shift keyed (FSK) signal. 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 that 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) The 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) The microcontroller and the base station each have their own resonator.

The base station IC has an on-chip PLL that generates a clock frequency of 16 MHz for internal clock supply only. The TMS3705BDRG4 and TMS3705DDRG4 are optimized for higher communication data rates and, therefore, work without frequency measurement during the write phase.

Features

  • Base Station IC for TI-RFid RF Identification Systems
  • Drives Antenna
  • Sends Modulated Data to Antenna
  • Detects and Demodulates Transponder Response (FSK)
  • Short-Circuit Protection
  • Diagnosis
  • Sleep-Mode Supply Current: 0.2 mA
  • Designed for Automotive Requirements
  • 16-Pin SOIC (D) Package

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Communication Interface
EPROM (KB)
Pin/Package
Standard
Operating Temperature Range (°C)
Flash (KB)
Encryption
Dimensions (mm)
Required antenna inductance (µH)
Supply voltage (Vdc)
Transmission Principle
Package
Current Supply (mA)
Rating
Frequency
Device Type
Data Rate (Max) (kbps)
Supply Voltage
Channels
I/O (Count)
TMS3705
I/O Logic    
-    
16SOIC    
ISO 11785    
-40 to +85    
-    
-    
10 x 6    
100 to 1000    
4.5 to 5.5    
HDX - FSK    
SO16    
8 Typ    
Catalog    
134.2 kHz    
Reader    
8    
4.5 to 5.5V    
1    
-