Microchip MCP3204-CI/ST 12-Bit 4-Channel SPI ADC: Datasheet, Pinout, and Application Circuit Guide

In the realm of embedded systems and data acquisition, the ability to accurately convert real-world analog signals into digital values is fundamental. The MCP3204-CI/ST from Microchip Technology stands as a robust and popular solution for these needs. This 12-bit, 4-channel Analog-to-Digital Converter (ADC) communicates via the ubiquitous SPI protocol, making it an excellent choice for integration with a vast array of microcontrollers and microprocessors. This guide delves into its core specifications, pinout configuration, and a practical application circuit to get you started.

Datasheet Overview and Key Specifications

The MCP3204's datasheet reveals a component designed for performance and flexibility. Its key specifications form the foundation of its capabilities:

Resolution: 12-bit resolution provides 4096 (2^12) discrete digital output codes, offering a fine granularity for precise measurements.

Input Channels: It features 4 single-ended or 2 pseudo-differential input channels (CH0-CH3), providing flexibility for different sensor types and measurement scenarios.

Interface: The serial peripheral interface (SPI) is simple and widely supported, enabling easy communication with host controllers.

Sampling Rate: It supports a maximum sampling rate of 100 kilosamples per second (ksps) at 5V, suitable for many medium-speed applications like temperature monitoring or potentiometer reading.

Supply Voltage: It operates over a broad voltage range of 2.7V to 5.5V, making it compatible with both 3.3V and 5V systems.

Package: The MCP3204-CI/ST comes in a TSSOP-14 package, which is compact for space-constrained PCB designs.

Pinout Configuration and Description

Understanding the pinout is crucial for correct circuit design. The MCP3204 in a TSSOP-14 package has the following key pins:

1. CH0-CH3 (Pins 1-4): Analog input channels 0 through 3.

2. VREF (Pin 5): Reference voltage input. The voltage applied here defines the analog input range. For maximum accuracy, use a stable, low-noise voltage source.

3. AGND (Pin 6): Analog ground.

4. CLK (Pin 7): Serial Clock input pin for the SPI communication.

5. DIN (Pin 8): Serial Data Input pin from the microcontroller.

6. DOUT (Pin 9): Serial Data Output pin to the microcontroller.

7. CS/SHDN (Pin 10): Chip Select/Shutdown input. Active-low; the device is active when this pin is low.

8. DGND (Pin 11): Digital ground.

9. VDD (Pin 14): Positive power supply pin (2.7V - 5.5V).

Pins 12 and 13 are not connected (N.C.).

Typical Application Circuit Guide

A basic connection circuit between the MCP3204 and an MCU like an Arduino or PIC microcontroller is straightforward.

1. Power and Ground: Connect VDD to the system's positive rail (e.g., 5V or 3.3V). Decouple this pin with a 100nF ceramic capacitor placed close to the IC, connecting it to ground. Tie AGND and DGND directly to the system's analog ground plane for best noise performance.

2. Reference Voltage: Connect VREF to a stable voltage source. This can be the same as VDD for simplicity, but for higher accuracy, use a dedicated precision voltage reference IC.

3. SPI Bus Connections: Link the SPI pins from the MCU to the ADC:

MCU MOSI -> DIN (Pin 8)

MCU MISO -> DOUT (Pin 9)

MCU SCK -> CLK (Pin 7)

MCU GPIO Pin -> CS/SHDN (Pin 10)

4. Analog Inputs: Connect your analog sensors (e.g., a thermistor via a voltage divider) to the desired channel (e.g., CH0). Ensure the input signal does not exceed the range of GND to VREF.

The software implementation involves pulling the CS pin low, sending a configuration command (specifying the channel and single/differential mode), and then reading the 12-bit result over the next 13 clock cycles.

ICGOOODFIND

The Microchip MCP3204-CI/ST is a highly versatile and cost-effective 12-bit ADC solution for a multitude of embedded applications. Its simple 4-wire SPI interface, multiple input channels, and wide operating voltage range make it an indispensable component for designers needing reliable analog-to-digital conversion. Whether you're building a data logger, a sensor node, or a control system, the MCP3204 provides a perfect blend of performance and ease of use.

Keywords:

1. SPI Interface

2. 12-Bit Resolution

3. Analog-to-Digital Converter (ADC)

4. Input Channels

5. Reference Voltage (VREF)