SNOSCY5B August   2014  – April 2015 FDC1004


  1. Features
  2. Applications
  3. Description
  4. Typical Application
  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 Characteristicsnote to Electrical Characteristics table
    6. 7.6 I2C Interface Voltage Level
    7. 7.7 I2C Interface Timing
    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 The Shield
      2. 8.3.2 The CAPDAC
      3. 8.3.3 Capacitive System Offset Calibration
      4. 8.3.4 Capacitive Gain Calibration
    4. 8.4 Device Functional Modes
      1. 8.4.1 Single Ended Measurement
      2. 8.4.2 Differential Measurement
    5. 8.5 Programming
      1. 8.5.1 Serial Bus Address
      2. 8.5.2 Read/Write Operations
      3. 8.5.3 Device Usage
        1. Measurement Configuration
        2. Triggering Measurements
        3. Wait for Measurement Completion
        4. Read of Measurement Result
    6. 8.6 Register Maps
      1. 8.6.1 Registers
        1. Capacitive Measurement Registers
      2. 8.6.2 Measurement Configuration Registers
      3. 8.6.3 FDC Configuration Register
      4. 8.6.4 Offset Calibration Registers
      5. 8.6.5 Gain Calibration Registers
      6. 8.6.6 Manufacturer ID Register
      7. 8.6.7 Device ID Register
  9. Applications and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Liquid Level Sensor
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Performance Plot
    3. 9.3 Do's and Don'ts
    4. 9.4 Initialization Set Up
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Trademarks
    3. 12.3 Electrostatic Discharge Caution
    4. 12.4 Glossary
  13. 13Mechanical, Packaging, and Orderable Information



7 Specifications

7.1 Absolute Maximum Ratings(1)

Input voltage VDD –0.3 6 V
SCL, SDA –0.3 6 V
at any other pin –0.3 VDD+0.3 V
Input current at any pin 3 mA
Junction temperature(2) 150 °C
Storage temperature TSTG –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.
(2) The maximum power dissipation is a function of TJ(MAX), RθJA, and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is PDMAX = (TJ(MAX) - TA)/ RθJA. All numbers apply for packages soldered directly onto a PC board.

7.2 ESD Ratings

V(ESD) Electrostatic discharge(1) Human body model (HBM), per ANSI/ESDA/JEDEC JS-001, all pins(2) ±1000 V
Charged device model (CDM), per JEDEC specification -500 500 JESD22-C101, all pins(3) ±250
(1) Electrostatic discharge (ESD) to measure device sensitivity and immunity to damage caused by assembly line electrostatic discharges in to the device.
(2) Level listed above is the passing level per ANSI, ESDA, and JEDEC JS-001. JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(3) Level listed above is the passing level per EIA-JEDEC JESD22-C101. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

7.3 Recommended Operating Conditions

Over operating temperature range (unless otherwise noted)
Supply voltage (VDD-GND) 3 3.3 3.6 V
Temperature –40 125 °C

7.4 Thermal Information

RθJA Junction-to-ambient thermal resistance 46.8 46.8 °C/W
RθJC Junction-to-case(top) thermal resistance 46.7 48.7 °C/W
RθJB Junction-to-board thermal resistance 21.5 70.6 °C/W
(1) For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.

7.5 Electrical Characteristics(1)

Over recommended operating temperature range, VDD = 3.3 V, for TA = 25°C (unless otherwise noted).
IDD Supply current Conversion mode; Digital input to VDD or GND 750 950 µA
Standby; Digital input to VDD or GND 29 70 µA
ICR Input conversion range ±15 pF
COMAX Max input offset capacitance per channel, Series resistance at CINn n=1.4 = 0 Ω 100 pF
RES Effective resolution (4) Sample rate = 100S/s (5) 16 bit
EON Output noise Sample rate = 100S/s (5) 33.2 aF/√Hz
ERR Absolute error after offset calibration ±6 fF
TcCOFF Offset deviation over temperature -40°C < T < 125°C 46 fF
GERR Gain error 0.2 %
tcG Gain drift vs. temperature -40°C < T < 125°C -37.5 ppm/°C
PSRR DC power supply rejection 3 V < VDD < 3.6 V, single-ended mode (channel vs GND) 13.6 fF/V
FRCAPDAC Full-scale range 96.9 pF
TcCOFFCAPDAC Offset drift vs. temperature -40°C < T < 125°C 30 fF
ƒ Frequency 25 kHz
VAC AC voltage across capacitance 2.4 Vpp
VDC Average DC voltage across capacitance 1.2 V
DRV Driver capability ƒ = 25 kHz, SHLDn to GND, n = 1,2 400 pF
(1) Electrical Characteristics Table values apply only for factory testing conditions at the temperature indicated. Factor 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 25Degree 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) Effective resolution is the ratio of converter full scale range to RMS measurement noise.
(5) No external capacitance connected.

7.6 I2C Interface Voltage Level

Over recommended operating free-air temperature range, VDD = 3.3 V, for TA = TJ = 25°C (unless otherwise noted).
VIH Input high voltage 0.7*VDD V
VIL Input low voltage 0.3*VDD V
VOL Output low voltage Sink current 3 mA 0.4 V
HYS Hysteresis (1) 0.1*VDD V
(1) This parameter is specified by design and/or characterization and is not tested in production.

7.7 I2C Interface Timing

Over recommended operating free-air temperature range, VDD = 3.3 V, for TA = TJ = 25°C (unless otherwise noted).
fSCL Clock frequency(1) 10 400 kHz
tLOW Clock low time(1) 1.3 µs
tHIGH Clock high time(1) 0.6 µs
tHD;STA Hold time (repeated) START condition(1) After this period, the first clock pulse is generated 0.6 µs
tSU;STA Set-up time for a repeated START condition(1) 0.6 µs
tHD;DAT Data hold time(1)(2) 0 ns
tSU;DAT Data setup time(1) 100 ns
tf SDA fall time(1) IL ≤ 3mA; CL ≤ 400pF 300 ns
tSU;STO Set-up time for STOP condition(1) 0.6 µs
tBUF Bus free time between a STOP and START condition(1) 1.3 µs
tVD;DAT Data valid time(1) 0.9 ns
tVD;ACK Data valid acknowledge time(1) 0.9 ns
tSP Pulse width of spikes that must be suppressed by the input filter(1) 50 ns
(1) This parameter is specified by design and/or characterization and is not tested in production.
(2) The FDC1004 provides an internal 300 ns minimum hold time to bridge the undefined region of the falling edge of SCL.
FDC1004 I2C_TIMING.gifFigure 1. I2C Timing

7.8 Typical Characteristics

FDC1004 D002_SNOSCZ4.gif
Figure 2. Active Conversion Mode Supply Current vs. Temperature
FDC1004 D004_SNOSCZ4.gif
Figure 4. Gain Drift vs. Temperature
FDC1004 D005_SNOSCZ4.gif
Capacitance Value = 10pF
Figure 6. Capacitance vs Voltage
FDC1004 D050_SNOSCY5.gif
Figure 8. Frequency Response 200S/s
FDC1004 D001_SNOSCZ4.gif
Figure 3. Stand-by Mode Supply Current vs. Temperature
FDC1004 D003_SNOSCZ4.gif
CINn = open, where n = 1...4
Figure 5. Offset Drift vs. Temperature
FDC1004 D049_SNOSCY5.gif
Figure 7. Frequency Response 100S/s
FDC1004 D051_SNOSCY5.gif
Figure 9. Frequency Response 400S/s