MCP3422/3/4
18-Bit, Multi-Channel
ΔΣ
Analog-to-Digital Converter with
I
2
C™ Interface and On-Board Reference
Features
• 18-bit
ΔΣ
ADC with Differential Inputs:
- 2 channels: MCP3422 and MCP3423
- 4 channels: MCP3424
• Differential Input Full Scale Range: -V
REF
to
+V
REF
• Self Calibration of Internal Offset and Gain per
Each Conversion
• On-Board Voltage Reference (V
REF
):
- Accuracy: 2.048V ± 0.05%
- Drift: 15 ppm/°C
• On-Board Programmable Gain Amplifier (PGA):
- Gains of 1, 2, 4 or 8
• INL: 10 ppm of Full Scale Range
• Programmable Data Rate Options:
- 3.75 SPS (18 bits)
- 15 SPS (16 bits)
- 60 SPS (14 bits)
- 240 SPS (12 bits)
• One-Shot or Continuous Conversion Options
• Low Current Consumption:
- 135 µA typical
(V
DD
= 3V, Continuous Conversion)
- 36 µA typical
(V
DD
= 3V, One-Shot Conversion with 1 SPS)
• On-Board Oscillator
• I
2
C
™
Interface:
- Standard, Fast and High Speed Modes
- User configurable two external address pins
for MCP3423 and MCP3424
• Single Supply Operation: 2.7V to 5.5V
• Extended Temperature Range: -40°C to +125°C
Description
The MCP3422, MCP3423 and MCP3424 devices
(MCP3422/3/4) are the low noise and high accuracy
18-Bit delta-sigma analog-to-digital (ΔΣ A/D) converter
family members of the MCP342X series from Microchip
Technology Inc. These devices can convert analog
inputs to digital codes with up to 18 bits of resolution.
The on-board 2.048V reference voltage enables an
input range of
±
2.048V differentially (full scale
range = 4.096V/PGA).
These devices can output analog-to-digital conversion
results at rates of 3.75, 15, 60, or 240 samples per
second depending on the user controllable
configuration bit settings using the two-wire I
2
C serial
interface. During each conversion, the device
calibrates offset and gain errors automatically. This
provides accurate conversion results from conversion
to conversion over variations in temperature and power
supply fluctuation.
The user can select the PGA gain of x1, x2, x4, or x8
before the analog-to-digital conversion takes place.
This allows the MCP3422/3/4 devices to convert a very
weak input signal with high resolution.
The MCP3422/3/4 devices have two conversion
modes: (a) One-Shot Conversion mode and (b)
Continuous Conversion mode. In One-Shot conversion
mode, the device performs a single conversion and
enters a low current standby mode automatically until it
receives another conversion command. This reduces
current consumption greatly during idle periods. In
Continuous conversion mode, the conversion takes
place continuously at the set conversion speed. The
device updates its output buffer with the most recent
conversion data.
The devices operate from a single 2.7V to 5.5V power
supply and have a two-wire I
2
C compatible serial
interface for a standard (100 kHz), fast (400 kHz), or
high-speed (3.4 MHz) mode.
The I
2
C address bits for the MCP3423 and MCP3424
are selected by using two external I
2
C address
selection pins (Adr0 and Adr1). The user can configure
the device to one of eight available addresses by
connecting these two address selection pins to V
DD
,
V
SS
or float. The I
2
C address bits of the MCP3422 are
programmed at the factory during production.
Typical Applications
• Portable Instrumentation and Consumer Goods
• Temperature Sensing with RTD, Thermistor, and
Thermocouple
• Bridge Sensing for Pressure, Strain, and Force
• Weigh Scales
• Battery Fuel Gauges
• Factory Automation Equipment
©
2009 Microchip Technology Inc.
DS22088C-page 1
MICROCHIP [ MICROCHIP TECHNOLOGY ]
