SNOSCZ7A December   2015  – January 2016 LDC0851

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Simplified Schematic
  5. Revision History
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Interface Voltage Levels
    7. 7.7 Timing Requirements
    8. 7.8 Typical Characteristics
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Basic Operation Mode
      2. 8.3.2 Threshold Adjust Mode
      3. 8.3.3 Setting the Threshold Adjust Values
      4. 8.3.4 Hysteresis
      5. 8.3.5 Conversion Time
      6. 8.3.6 Power-Up Conditions
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
  9. Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Sensor Design
        1. 9.1.1.1 Sensor Frequency
        2. 9.1.1.2 Sensor Design Procedure
    2. 9.2 Typical Application
      1. 9.2.1 Event Counting
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Coarse Position Sensing
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Low Power Operation
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
      1. 11.2.1 Side by Side Coils
      2. 11.2.2 Stacked Coils
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7 Specifications

7.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1)
MIN MAX UNIT
VDD Supply Voltage Range 3.6 V
Vi Voltage on LSENSE, LREF, and EN -0.3 3.6 V
Voltage on ADJ and LCOM -0.3 2 V
IA Current LSENSE, LREF, and VOUT 5 mA
TJ Junction Temperature -55 150 °C
Tstg Storage Temperature -65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

7.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±1000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±250
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VDD Supply Voltage 1.71 3.46 V
TA Operating Temperature -40 125 °C

7.4 Thermal Information

over operating free-air temperature range (unless otherwise noted)
THERMAL METRIC(1) LDC0851 UNIT
DSG (WSON)
8 PINS
RθJA Junction-to-ambient thermal resistance 67.4 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 89.3 °C/W
RθJB Junction-to-board thermal resistance 37.3 °C/W
ψJT Junction-to-top characterization parameter 2.4 °C/W
ψJB Junction-to-board characterization parameter 37.7 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 9.2 °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report (SPRA953).

7.5 Electrical Characteristics(1)

Over recommended operating conditions unless otherwise noted. VDD= 3.3 V, EN tied to 3.3 V, TA=25 °C, ADJ tied to GND.
PARAMETER TEST CONDITIONS MIN(2) TYP(3) MAX(2) UNIT
POWER
VDD Supply Voltage 1.71 3.46 V
ISTATIC Static Supply Current (4) 0.70 mA
IDYN Dynamic Supply Current (not including sensor current)(4) ƒSENSOR = 15 MHz

CPARASITIC = 22 pF

0.66 mA
ISD Shutdown Mode Supply Current 0.14 1 µA
SENSOR
ISENSOR_MAX Maximum sensor current(4) VDD = 1.71 V 4.35 mA
VDD = 3.3 V 6 mA
LSENSOR_MIN Sensor Minimum Inductance(5) CTOTAL = 33 pF

VDD = 1.71 V

2.5
CTOTAL = 33 pF

VDD = 3.3 V

1.8 µH
ƒSENSOR_MAX Max Sensor Resonant Frequency(5) Sensor inductance = 2 µH

CTOTAL = 33 pF

19 MHz
CTOTAL Minimum total capacitance on LCOM(5)

Includes parasitic pin capacitance and PCB parasitic capacitance

33 pF
CIN Pin parasitic capacitance on LCOM 12 pF
Pin parasitic capacitance on LREF and LSENSE 8 pF
DETECTION
dHYST Switching distance hysteresis(6) 2.5 %
dTOL Switching threshold tolerance(6) 0.1 %
THRESHOLD ADJUST
VADJ Adjust input range 0 VDD/2 V
VADJ_TOL Adjust threshold tolerance ± 6 mV
(1) Electrical Characteristics Table values apply only for factory testing conditions at the temperature indicated. Factory testing conditions result in very limited self-heating of the device such that TJ = TA. No guarantee of parametric performance is indicated in the electrical tables under conditions of internal self-heating where TJ > TA. Absolute Maximum Ratings indicate junction temperature limits beyond which the device may be permanently degraded, either mechanically or electrically.
(2) Limits are ensured by testing, design, or statistical analysis at 25°C. Limits over the operating temperature range are ensured through correlations using statistical quality control (SQC) method.
(3) Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will also depend on the application and configuration. The typical values are not tested and are not guaranteed on shipped production material.
(4) Refer to section Active Mode for a description and calculation of the various supply currents.
(5) See Sensor Design for sensor guidance.
(6) Two matched 10 mm diameter sensors were used with a switching distance of 3 mm. See Hysteresis for more information.

7.6 Interface Voltage Levels

PARAMETER MIN TYP MAX UNIT
VIH Input High Voltage 0.8ˣVDD V
VIL Input Low Voltage 0.2ˣVDD V
VOH Output High Voltage(1mA source current) VDD-0.4 V
VOL Output Low Voltage (1mA sink current) 0.4 V

7.7 Timing Requirements

Over recommended operating conditions unless otherwise noted. VDD= 3.3 V, EN tied to 3.3 V, TA=25 °C, ADJ tied to GND.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
VOLTAGE LEVELS
tCONVERSION Conversion time ƒSENSOR = 15 MHz 290 µs
tDELAY Output delay time (Response time) ƒSENSOR = 15 MHz 580 µs
tSTART Start-up time 450 µs
tAMT Shutdown-to-active mode transition time 450 µs
tSMT Active-to-shutdown mode transition time <1 µs
LDC0851 startup_delay_timing_diagram_snoscz7.gif Figure 1. Start-up and Delay Time Diagram

Refer to Power-Up Conditions for more information on the Power-On Start State.

LDC0851 shutdown_resume_active_timing_diagram_snoscz7.gif Figure 2. Shutdown and Resume Active Mode Timing Diagram

7.8 Typical Characteristics

Common test conditions (unless specified otherwise): VDD = 3.3 V, Sense coil diameter = reference coil diameter, Target: Aluminum, 1.5 mm thickness, Target area / Coil area > 100%
LDC0851 D001_SNOSCZ7.gif
Basic Operation Mode ADJ Code = 0
Coil diameter = 10 mm
Figure 3. Switching Distance vs. LREF Target Distance
LDC0851 D003_SNOSCZ7.gif
Basic Operation Mode ADJ Code = 0
Coil diameter = 6 mm, 15 mm, 29 mm
Figure 5. Normalized Switching Distance vs. LREF Target Distance
LDC0851 D005_SNOSCZ7.gif
LSENSE frequency (fs) varied LREF frequency (fr) fixed
Figure 7. Frequency vs. Distance
LDC0851 D007_SNOSCZ7.png
ISENSOR_MAX = 4.35 mA
Specified for closest target proximity or minimum inductance in the application.
Figure 9. Sensor Design Space for VDD = 1.8 V
LDC0851 D009_alt2_SNOSCZ7.gif
CTOTAL = 100 pF
Figure 11. ISENSOR vs. VDD
LDC0851 D011_SNOSCZ7.gif Figure 13. ISTATIC vs. VDD
LDC0851 D013_SNOSCZ7.gif Figure 15. ISENSOR vs. ƒSENSOR
LDC0851 D002_SNOSCZ7.gif
Threshold Adjust Mode No reference target
Coil diameter = 10 mm
Figure 4. Switching Distance vs. ADJ code
LDC0851 D004_SNOSCZ7.gif
Threshold Adjust Mode No reference target
Coil diameter = 6 mm, 15 mm, 29 mm
Figure 6. Normalized Switching Distance vs. ADJ Code
LDC0851 D006_SNOSCZ7.gif
LSENSE inductance (Ls) varied LREF inductance (Lr) fixed
Figure 8. Inductance vs. Distance
LDC0851 D008_SNOSCZ7.png
ISENSOR_MAX = 6 mA
Specified for closest target proximity or minimum inductance in the application.
Figure 10. Sensor Design Space for VDD = 3.3 V
LDC0851 D010_SNOSCZ7.gif
CBOARD = 12 pF
ƒSENSOR = 30 MHz
Figure 12. IDYN vs. VDD
LDC0851 D012_alt_SNOSCZ7.gif Figure 14. ISD vs. VDD
LDC0851 D014_SNOSCZ7.gif
Normalized to frequency at VDD = 3.6 V
Figure 16. ƒSENSOR Shift vs. VDD