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
MCP3422/3/4
The MCP3422 and MCP3423 devices have two
differential input channels and the MCP3424 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.
The MCP3422 is available in 8-pin SOIC, DFN, and
MSOP packages. The MCP3423 is available in 10-pin
DFN, and MSOP packages. The MCP3424 is available
in 14-pin SOIC and TSSOP packages.
Package Types
MCP3422
MSOP, SOIC
CH1+ 1
CH1- 2
V
DD
3
SDA 4
8 CH2-
7 CH2+
6 V
SS
5 SCL
CH1+ 1
CH1- 2
3
V
SS
CH2+ 4
CH2- 5
MCP3423
MSOP
10 Adr1
9
Adr0
8 SCL
7 SDA
6 V
DD
MCP3424
SOIC, TSSOP
CH1+
CH1-
CH2+
CH2-
V
SS
V
DD
SDA
1
2
14
13
3
4
5
6
7
12
11
10
9
8
MCP3422
2x3 DFN*
CH1+
1
CH1-
2
MCP3423
3x3 DFN*
CH1+
1
CH1-
2
V
SS
3
CH2+
4
CH2-
5
CH4-
CH4+
CH3-
CH3+
Adr1
Adr0
SCL
V
DD
3
SDA 4
EP
9
* Includes Exposed Thermal Pad (EP); see
Table 3-1.
Functional Block Diagram
V
SS
MCP3422
V
DD
CH1-
CH2+
CH2-
MUX
DS22088C-page 2
MCP3422
MCP3423
MCP3424
8
CH2-
7
CH2+
6 V
SS
5 SCL
10
Adr1
9
Adr0
EP
11
8 SCL
7 SDA
6 V
DD
Voltage Reference
(2.048V)
V
REF
CH1+
PGA
ΔΣ
ADC
Converter
I
2
C
Interface
SCL
SDA
Gain = 1,2,4, or 8
Clock
Oscillator
©
2009 Microchip Technology Inc.
MCP3422/3/4
1.0
ELECTRICAL
CHARACTERISTICS
†Notice:
Stresses above those listed under “Maximum Rat-
ings” 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
.
Absolute Maximum Ratings†
V
DD
...................................................................................7.0V
All inputs and outputs ............. ..........V
SS
–0.4V to V
DD
+0.4V
Differential Input Voltage ...................................... |V
DD
- V
SS
|
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 (T
J
). .........................+150°C
ELECTRICAL CHARACTERISTICS
Electrical Specifications:
Unless otherwise specified, all parameters apply for T
A
= -40°C to +85°C, V
DD
= +5.0V, V
SS
= 0V,
CHn+ = CHn- = V
REF
/2, V
INCOM
= V
REF
/2. All ppm units use 2*V
REF
as differential full scale range.
Parameters
Analog Inputs
Differential Full Scale Input
Voltage Range
Maximum Input Voltage Range
Differential Input Impedance
Common Mode input
Impedance
System Performance
Resolution and No Missing
Codes
(Effective Number of Bits)
(Note 3)
Data Rate
(Note 4)
DR
12
14
16
18
176
44
11
2.75
Output Noise
Integral Non-Linearity
Internal Reference Voltage
Gain Error
(Note 6)
Note 1:
INL
V
REF
—
—
—
—
—
—
—
—
240
60
15
3.75
1.5
10
2.048
0.05
—
—
—
—
328
82
20.5
5.1
—
35
—
0.35
Bits
Bits
Bits
Bits
SPS
SPS
SPS
SPS
µV
RMS
DR = 240 SPS
DR = 60 SPS
DR = 15 SPS
DR = 3.75 SPS
12 bits mode
14 bits mode
16 bits mode
18 bits mode
T
A
= +25°C, DR = 3.75 SPS,
PGA = 1, V
IN
+ = V
IN
- = GND
DR = 3.75 SPS, FSR = Full
Scale Range
(Note 5)
Z
IND
(f)
Z
INC
(f)
FSR
—
V
SS
-0.3
—
—
±2.048/PGA
—
2.25/PGA
25
—
V
DD
+0.3
—
—
V
V
MΩ
MΩ
V
IN
= [CHn+ - CHn-]
(Note 1)
During normal mode operation
(Note 2)
PGA = 1, 2, 4, 8
Sym
Min
Typ
Max
Units
Conditions
ppm of
FSR
V
%
PGA = 1, DR = 3.75 SPS
Any input voltage below or greater than this voltage causes leakage current through the ESD diodes at the input pins.
This parameter is ensured by characterization and not 100% tested.
2:
This input impedance is due to 3.2 pF internal input sampling capacitor.
3:
This parameter is ensured by design and not 100% tested.
4:
The total conversion speed includes auto-calibration of offset and gain.
5:
INL is the difference between the endpoints line and the measured code at the center of the quantization band.
6:
Includes all errors from on-board PGA and V
REF
.
7:
This parameter is ensured by characterization and not 100% tested.
8:
MCP3423 and MCP3424 only.
9:
Addr_Float voltage is applied at address pin.
10:
No voltage is applied at address pin (left “floating”).
©
2009 Microchip Technology Inc.
DS22088C-page 5
编程基础
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