
4
Analog Front End IC TMS37122 - Reference Guide
August ’01
Document Overview
Page
Chapter 1: Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1
General Features................................................................................. 7
1.2
References........................................................................................... 7
1.3
Circuit Description................................................................................ 8
Chapter 2: Electrical Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.1
General.............................................................................................. 15
2.2
Power Supply..................................................................................... 17
2.3
Power-on-reset .................................................................................. 22
2.4
Limiter Circuits................................................................................... 23
2.5
Wake Detector................................................................................... 24
2.6
End-of-burst Detector......................................................................... 25
2.7
Pulse Position Demodulator............................................................... 25
2.8
Control Unit........................................................................................ 26
2.9
FSK Modulator................................................................................... 31
2.10 Configuration Memory........................................................................ 32
2.11 Resonant Circuit Trimming ................................................................ 44
Chapter 3: Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
3.1
Passive Entry Function...................................................................... 49
3.2
Passive Start Function....................................................................... 52
3.3
Battery Backup Function.................................................................... 54
3.4
Immobilizer Function.......................................................................... 56
3.5
Anti-Collision Function....................................................................... 56
Chapter 4: Product Specification Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.1
Absolute Maximum Ratings............................................................... 59
4.2
Recommended System Operating Conditions................................... 60
List of Figures
Page
Figure 1: TSSOP Package (Top View) .......................................................... 7
Figure 2: System Arrangement of 3D-Analog Front End IC TMS37122........ 8
Figure 3: Typical 3D-AFE Application Including Battery Backup Function... 10
Figure 4: Block Schematic of TMS37122..................................................... 16
Figure 5: Standard Battery Supply - Schematic........................................... 17
Figure 6: Schematic for Rechargeable Battery Supply................................ 18
Figure 7: Schematic for Battery Backup Supply........................................... 19
Figure 8: Test Arrangement with Digital Interface Test Box and PC............ 21
Figure 9: Schematic of Reset Flow.............................................................. 22
Figure 10: TMS37122 Limiter Circuits.......................................................... 23
Figure 11: Block schematic of Wake Detector............................................. 24
Figure 12: EOB Detector and Pulse Position Modulator Function............... 25
Figure 13: Overall State Diagram of Control Unit......................................... 27
Figure 14: Initialization State Diagram of TMS37122................................... 28
Figure 15: Control Unit Timing Diagram....................................................... 29
Figure 16: Wake Pattern Detection State Diagram...................................... 30
Figure 17: State Diagram of Transparent Mode........................................... 31