Datasheet MCP3422, MCP3423, MCP3424 (Microchip)

MCP3422/3/4 18-Bit, Multi-Channel
ΔΣ
Analog-to-Digital Converter with I2C™ Interface and On-Board Reference Features Description
• 18-bit ΔΣ ADC with Differential Inputs: The MCP3422, MCP3423 and MCP3424 devices - 2 channels: MCP3422 and MCP3423 (MCP3422/3/4) are the low noise and high accuracy - 4 channels: MCP3424 18-Bit delta-sigma analog-to-digital (ΔΣ A/D) converter family members of the MCP342X series from Microchip • Differential Input Full Scale Range: -VREF to Technology Inc. These devices can convert analog +VREF inputs to digital codes with up to 18 bits of resolution. • Self Calibration of Internal Offset and Gain per Each Conversion The on-board 2.048V reference voltage enables an input range of ± 2.048V differentially (full scale • On-Board Voltage Reference (VREF): range = 4.096V/PGA). - Accuracy: 2.048V ± 0.05% These devices can output analog-to-digital conversion - Drift: 15 ppm/°C results at rates of 3.75, 15, 60, or 240 samples per • On-Board Programmable Gain Amplifier (PGA): second depending on the user controllable - Gains of 1, 2, 4 or 8 configuration bit settings using the two-wire I2C serial • INL: 10 ppm of Full Scale Range interface. During each conversion, the device • Programmable Data Rate Options: calibrates offset and gain errors automatically. This provides accurate conversion results from conversion - 3.75 SPS (18 bits) to conversion over variations in temperature and power - 15 SPS (16 bits) supply fluctuation. - 60 SPS (14 bits) The user can select the PGA gain of x1, x2, x4, or x8 - 240 SPS (12 bits) before the analog-to-digital conversion takes place. • One-Shot or Continuous Conversion Options This allows the MCP3422/3/4 devices to convert a very • Low Current Consumption: weak input signal with high resolution. - 135 µA typical The MCP3422/3/4 devices have two conversion (VDD= 3V, Continuous Conversion) modes: (a) One-Shot Conversion mode and (b) - 36 µA typical Continuous Conversion mode. In One-Shot conversion (VDD= 3V, One-Shot Conversion with 1 SPS) mode, the device performs a single conversion and • On-Board Oscillator enters a low current standby mode automatically until it • I2C™ Interface: receives another conversion command. This reduces current consumption greatly during idle periods. In - Standard, Fast and High Speed Modes Continuous conversion mode, the conversion takes - User configurable two external address pins place continuously at the set conversion speed. The for MCP3423 and MCP3424 device updates its output buffer with the most recent • Single Supply Operation: 2.7V to 5.5V conversion data. • Extended Temperature Range: -40°C to +125°C The devices operate from a single 2.7V to 5.5V power supply and have a two-wire I2C compatible serial
Typical Applications
interface for a standard (100 kHz), fast (400 kHz), or high-speed (3.4 MHz) mode. • Portable Instrumentation and Consumer Goods • Temperature Sensing with RTD, Thermistor, and The I2C address bits for the MCP3423 and MCP3424 Thermocouple are selected by using two external I2C address selection pins (Adr0 and Adr1). The user can configure • Bridge Sensing for Pressure, Strain, and Force the device to one of eight available addresses by • Weigh Scales connecting these two address selection pins to VDD, • Battery Fuel Gauges VSS or float. The I2C address bits of the MCP3422 are • Factory Automation Equipment programmed at the factory during production. © 2009 Microchip Technology Inc. DS22088C-page 1 Document Outline 1.0 Electrical Characteristics 2.0 Typical Performance Curves FIGURE 2-1: INL vs. Supply Voltage (VDD). FIGURE 2-2: INL vs. Temperature. FIGURE 2-3: Offset Error vs. Temperature. FIGURE 2-4: Output Noise vs. Input Voltage. FIGURE 2-5: Total Error vs. Input Voltage. FIGURE 2-6: Gain Error vs. Temperature. FIGURE 2-7: IDDA vs. Temperature. FIGURE 2-8: IDDS vs. Temperature. FIGURE 2-9: IDDB vs. Temperature. FIGURE 2-10: Oscillator Drift vs. Temperature. FIGURE 2-11: Frequency Response. 3.0 Pin Descriptions TABLE 3-1: PIN Function Table 3.1 Analog Inputs (CHn+, CHn-) 3.2 Supply Voltage (VDD, VSS) FIGURE 3-1: Equivalent Analog Input Circuit. 3.3 Serial Clock Pin (SCL) 3.4 Serial Data Pin (SDA) 3.5 Exposed Thermal Pad (EP) 4.0 Description of Device Operation 4.1 General Overview 4.2 Power-On-Reset (POR) FIGURE 4-1: POR Operation. 4.3 Internal Voltage Reference 4.4 Analog Input Channels 4.5 Input Voltage Range 4.6 Input Impedance 4.7 Aliasing and Anti-aliasing Filter 4.8 Self-Calibration 4.9 Digital Output Codes and Conversion to Real Values TABLE 4-1: Resolution Settings VS. LSB TABLE 4-2: Example of output code for 18 bits (Note 1, Note 2) TABLE 4-3: Minimum and Maximum Output codes (Note) TABLE 4-4: Example of converting output code to voltage (With 18 Bit Setting) 5.0 Using the Devices 5.1 Operating Modes 5.2 Configuration Register TABLE 5-1: Write Configuration Bits TABLE 5-2: READ Configuration Bits 5.3 I2C Serial Communications FIGURE 5-1: Address Byte. FIGURE 5-2: General Call Latch Command and Voltage Output at Address Pin Left “Floating” (MCP3423 and MCP3424). FIGURE 5-3: Timing Diagram For Writing To The MCP3422/3/4. TABLE 5-3: Output Codes of each Resolution OPTION FIGURE 5-4: Timing Diagram For Reading From The MCP3422/3/4 With 18-Bit Mode. FIGURE 5-5: Timing Diagram For Reading From The MCP3422/3/4 With 12-Bit to 16-Bit Modes. 5.4 General Call FIGURE 5-6: General Call Address Format. 5.5 High-Speed (HS) Mode 5.6 I2C Bus Characteristics FIGURE 5-7: Data Transfer Sequence on I2C Serial Bus. TABLE 5-4: I2c serial timing Specifications (Continued) FIGURE 5-8: I2C Bus Timing Data. 6.0 Basic Application Configuration 6.1 Connecting to the Application Circuits FIGURE 6-1: Typical Connection. FIGURE 6-2: Example of Multiple Device Connection on I2C Bus. FIGURE 6-3: I2C Bus Connection Test. FIGURE 6-4: Differential and Single- Ended Input Connections. 6.2 Application Examples FIGURE 6-5: Battery Voltage and Charging/Discharging Current Measurement. FIGURE 6-6: Four-Channel Thermocouple Applications. FIGURE 6-7: Example of Pressure and Temperature Measurement. 7.0 Development Tool Support 7.1 MCP3422/3/4 Evaluation Boards FIGURE 7-1: MCP3424 Evaluation Board. FIGURE 7-2: Setup for the MCP3424 Evaluation Board with PICkit™ Serial Analyzer. FIGURE 7-3: Example of PICkit™ Serial User Interface. 8.0 Packaging Information 8.1 Package Marking Information