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© 2009 Microchip Technology Inc. DS22226A-page 1
MCP3426/7/8
Features
• 16-bit ΔΣ ADC with Differential Inputs:
- 2 channels: MCP3426 and MCP3427
- 4 channels: MCP3428
• 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:
- 15 SPS (16 bits)
- 60 SPS (14 bits)
- 240 SPS (12 bits)
• One-Shot or Continuous Conversion Options
• Low Current Consumption (V
DD
= 3V):
- Continuous Conversion: 135 µA typical
- One-Shot Conversion with 1 SPS:
- 9 µA typical for 16 bit mode
- 2.25 µA typical for 14 bit mode
- 0.56 µA typical for 12 bit mode
• On-Board Oscillator
•I
2
C
™
Interface:
- Standard, Fast and High Speed Modes
- User configurable two external address
selection pins for MCP3427 and MCP3428
• Single Supply Operation: 2.7V to 5.5V
• Extended Temperature Range: -40°C to +125°C
Typical Applications
• Portable Instrumentation and Consumer Goods
• Temperature Sensing with RTD, Thermistor, and
Thermocouple
• Bridge Sensing for Pressure, Strain, and Force
• Weigh Scales and Battery Fuel Gauges
• Factory Automation Equipment
Description
The MCP3426, MCP3427 and MCP3428 devices
(MCP3426/7/8) are the low noise and high accuracy
16 Bit Delta-Sigma Analog-to-Digital (ΔΣ A/D) Con-
verter family members of the MCP342X series from
Microchip Technology Inc. These devices can convert
analog inputs to digital codes with up to 16 bits of reso-
lution.
The MCP3426 and MCP3427 devices have two
differential input channels and the MCP3428 has four
differential input channels. All electrical properties of
these three devices are the same except the
differences in the number of input channels and I
2
C
address bit selection options.
These devices can output analog-to-digital conversion
results at rates of 15 (16-bit mode), 60 (14-bit mode), or
240 (12-bit mode) 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 device has an on-board 2.048V reference voltage,
which enables an input range of ± 2.048V differentially
(full scale range = 4.096/PGA).
The user can select the gain of the on-board
programmable gain amplifier (PGA) using the
configuration register bits (gain of x1, x2, x4, or x8).
This allows the MCP3426/7/8 devices to convert a very
weak input signal with high resolution.
The MCP3426/7/8 devices have two conversion
modes: (a) One-Shot Conversion mode and
(b) Continuous Conversion mode. In the One-Shot
conversion mode, the device performs a single
conversion and enters a low current standby
(shutdown) 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 configured 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.
16-Bit, Multi-Channel ΔΣ Analog-to-Digital Converter with
I
2
C™ Interface and On-Board Reference
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