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MCP3425
16-Bit Analog-to-Digital Converter with I2C Interface and On-Board Reference
Features
• 16-bit ΔΣ ADC in a SOT-23-6 package • Differential Input Operation • Self Calibration of Internal Offset and Gain per each conversion • On-Board Voltage Reference: - Accuracy: 2.048V ± 0.05% • On-Board Programmable Gain Amplifier (PGA): - Gains of 1, 2, 4 or 8 • On-Board Oscillator • INL: 10 ppm of FSR (FSR = 4.096V/PGA) • Programmable Data Rate Options: - 15 SPS (16 bits) - 60 SPS (14 bits) - 240 SPS (12 bits) • One-Shot or Continuous Conversion Options • Low Current Consumption: - 145 µA typical (VDD= 3V, Continuous Conversion) • One-Shot Conversion (1 SPS) with VDD = 3V: - 9.7 µA typical with 16 bit mode - 2.4 µA typical with 14 bit mode - 0.6 µA typical with 12 bit mode • Supports I2C Serial Interface: - Standard, Fast and High-Speed Modes • Single Supply Operation: 2.7V to 5.5V • Extended Temperature Range: -40°C to 125°C
Description
The MCP3425 is a single channel low-noise, high accuracy ΔΣ A/D converter with differential inputs and up to 16 bits of resolution in a small SOT-23-6 package. The on-board precision 2.048V reference voltage enables an input range of ±2.048V differentially (Δ voltage = 4.096V). The device uses a two-wire I2C compatible serial interface and operates from a single 2.7V to 5.5V power supply. The MCP3425 device performs conversion at rates of 15, 60, or 240 samples per second (SPS) depending on the user controllable configuration bit settings using the two-wire I2C serial interface. This device has an on-board programmable gain amplifier (PGA). The user can select the PGA gain of x1, x2, x4, or x8 before the analog-to-digital conversion takes place. This allows the MCP3425 device to convert a smaller input signal with high resolution. The device has two conversion modes: (a) Continuous mode and (b) One-Shot mode. In One-Shot mode, the device enters a low current standby mode automatically after one conversion. This reduces current consumption greatly during idle periods. The MCP3425 device can be used for various high accuracy analog-to-digital data conversion applications where design simplicity, low power, and small footprint are major considerations.
Block Diagram
VSS VDD
Typical Applications
• Portable Instrumentation • Weigh Scales and Fuel Gauges • Temperature Sensing with RTD, Thermistor, and Thermocouple • Bridge Sensing for Pressure, Strain, and Force. Voltage Reference (2.048V) Gain = 1, 2, 4, or 8 VIN+ PGA ΔΣ ADC Converter Clock Oscillator VREF
Package Types
SOT-23-6 MCP3425 VIN6 5 4
VIN+ VSS SCL
1 2 3
VINVDD SDA
I2C Interface
SCL
SDA
© 2009 Microchip Technology Inc.
DS22072B-page 1
MCP3425
NOTES:
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DS22072B-page 2
© 2009 Microchip Technology Inc.
MCP3425
1.0
1.1
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ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings†
VDD...................................................................................7.0V All inputs and outputs w.r.t VSS ............... –0.3V to VDD+0.3V Differential Input Voltage ...................................... |VDD - VSS| Output Short Circuit Current ................................ Continuous Current at Input Pins ....................................................±2 mA Current at Output and Supply Pins ............................±10 mA Storage Temperature ....................................-65°C to +150°C Ambient Temp. with power applied ...............-55°C to +125°C ESD protection on all pins ................ ≥ 6 kV HBM, ≥ 400V MM Maximum Junction Temperature (TJ). .........................+150°C
†Notice: Stresses above those listed under “Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operational listings of this specification is not implied. Exposure to maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
Electrical Specifications: Unless otherwise specified, all parameters apply for TA = -40°C to +85°C, VDD = +5.0V, VSS = 0V, VIN+ = VIN- = VREF/2. All ppm units use 2*VREF as full-scale range.
Parameters
Analog Inputs Differential Input Range Common-Mode Voltage Range (absolute) (Note 1) Differential Input Impedance (Note 2) Common Mode input Impedance System Performance Resolution and No Missing Codes (Note 8)
Sym
Min
— VSS-0.3
Typ
±2.048/PGA — 2.25/PGA 25
Max
— VDD+0.3 — —
Units
V V MΩ MΩ
Conditions
VIN = VIN+ - VIN-
ZIND (f) ZINC (f)
— —
During normal mode operation PGA = 1, 2, 4, 8
12 14 16 DR 176 44 11
— — — 240 60 15 2.5 10 2.048 0.1 0.1 15
— — — 328 82 20.5 — — — — — —
Bits Bits Bits SPS SPS SPS µVRMS
DR = 240 SPS DR = 60 SPS DR = 15 SPS S1,S0 = ‘00’, (12 bits mode) S1,S0 = ‘01’, (14 bits mode) S1,S0 = ‘10’, (16 bits mode) TA = +25°C, DR = 15 SPS, PGA = 1, VIN = 0 DR = 15 SPS (Note 6)
Data Rate (Note 3)
Output Noise Integral Nonlinearity (Note 4.