18-Bit - Multi-Channel Delta-Sigma Analog-to-Digital ...

MCP3422/3/4

18-Bit, Multi-Channel ¦¤¦² Analog-to-Digital Converter with

I2C? Interface and On-Board Reference

Features

Description

? 18-bit ¦¤¦² ADC with Differential Inputs:

- 2 channels: MCP3422 and MCP3423

- 4 channels: MCP3424

? Differential Input Full Scale Range: -VREF to

+VREF

? Self Calibration of Internal Offset and Gain per

Each Conversion

? On-Board Voltage Reference (VREF):

- Accuracy: 2.048V ¡À 0.05%

- Drift: 15 ppm/¡ãC

? 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 ?A typical

(VDD= 3V, Continuous Conversion)

- 36 ?A typical

(VDD= 3V, One-Shot Conversion with 1 SPS)

? On-Board Oscillator

? I2C? 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¡ãC to +125¡ãC

The MCP3422, MCP3423 and MCP3424 devices

(MCP3422/3/4) are the low noise and high accuracy

18-Bit delta-sigma analog-to-digital (¦¤¦² 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.

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.

The on-board 2.048V reference voltage enables an

input range of ¡À 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 I2C 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 I2C compatible serial

interface for a standard (100 kHz), fast (400 kHz), or

high-speed (3.4 MHz) mode.

The I2C address bits for the MCP3423 and MCP3424

are selected by using two external I2C 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 VDD,

VSS or float. The I2C address bits of the MCP3422 are

programmed at the factory during production.

DS22088C-page 1

MCP3422/3/4

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.

The MCP3422 and MCP3423 devices have two

differential input channels and the MCP3424 has fourdifferential input channels. All electrical properties of

these three devices are the same except the

differences in the number of input channels and I2C

address bit selection options.

Package Types

MCP3422

MSOP, SOIC

SDA 4

CH1+ 1

CH1- 2

8 CH27 CH2+

6 VSS

5 SCL

3

VSS

CH2+ 4

CH2- 5

MCP3422

2x3 DFN*

CH1+ 1

CH1- 2

VDD 3

EP

9

SDA 4

10 Adr1

9

Adr0

8 SCL

7 SDA

6 VDD

MCP3423

3x3 DFN*

8 CH2-

CH1+ 1

7 CH2+

CH1- 2

CH1+

CH1-

1

14

2

13

CH2+

CH2VSS

3

VDD

SDA

6

9

7

8

4

5

MCP3424

CH1- 2

VDD 3

MCP3423

MCP3422

CH1+ 1

MCP3424

SOIC, TSSOP

MCP3423

MSOP

12

11

10

CH4CH4+

CH3CH3+

Adr1

Adr0

SCL

10 Adr1

9 Adr0

EP

11

6 VSS

VSS 3

5 SCL

CH2+ 4

7 SDA

CH2- 5

6 VDD

8 SCL

* Includes Exposed Thermal Pad (EP); see Table 3-1.

Functional Block Diagram

VDD

VSS

MCP3422

Voltage Reference

(2.048V)

VREF

CH1+

MUX

CH1-

SCL

PGA

¦¤¦² ADC

Converter

I2C

Interface

SDA

CH2+

CH2-

Gain = 1,2,4, or 8

Clock

Oscillator

DS22088C-page 2

? 2009 Microchip Technology Inc.

MCP3422/3/4

Functional Block Diagram

VSS

VDD

MCP3423

Adr1

Voltage Reference

(2.048V)

Adr0

VREF

CH1-

MUX

CH1+

¦¤¦² ADC

Converter

PGA

I2C

SCL

Interface

SDA

CH2+

CH2-

Gain = 1,2,4, or 8

Clock

Oscillator

Functional Block Diagram

VSS

VDD

MCP3424

CH1+

Adr1

Voltage Reference

(2.048V)

CH1-

Adr0

VREF

CH2-

MUX

CH2+

PGA

¦¤¦² ADC

Converter

CH3+

CH3CH4+

I2C

Interface

SCL

SDA

Gain = 1,2,4, or 8

Clock

Oscillator

CH4-

? 2009 Microchip Technology Inc.

DS22088C-page 3

MCP3422/3/4

NOTES:

DS22088C-page 4

? 2009 Microchip Technology Inc.

MCP3422/3/4

1.0

ELECTRICAL

CHARACTERISTICS

?Notice: Stresses above those listed under ¡°Maximum Ratings¡± 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?

VDD...................................................................................7.0V

All inputs and outputs ............. ..........VSS ¨C0.4V to VDD+0.4V

Differential Input Voltage ...................................... |VDD - VSS|

Output Short Circuit Current ................................ Continuous

Current at Input Pins ....................................................¡À2 mA

Current at Output and Supply Pins ............................¡À10 mA

Storage Temperature ....................................-65¡ãC to +150¡ãC

Ambient Temp. with power applied ...............-55¡ãC to +125¡ãC

ESD protection on all pins ................ ¡Ý 6 kV HBM, ¡Ý 400V MM

Maximum Junction Temperature (TJ). .........................+150¡ãC

ELECTRICAL CHARACTERISTICS

Electrical Specifications: Unless otherwise specified, all parameters apply for TA = -40¡ãC to +85¡ãC, VDD = +5.0V, VSS = 0V,

CHn+ = CHn- = VREF/2, VINCOM = VREF /2. All ppm units use 2*VREF as differential full scale range.

Parameters

Sym

Min

Typ

Max

Units

FSR

¡ª

¡À2.048/PGA

¡ª

V

Conditions

Analog Inputs

Differential Full Scale Input

Voltage Range

Maximum Input Voltage Range

VIN = [CHn+ - CHn-]

VSS-0.3

¡ª

VDD+0.3

V

Differential Input Impedance

ZIND (f)

¡ª

2.25/PGA

¡ª

M¦¸

During normal mode operation

(Note 2)

Common Mode input

Impedance

ZINC (f)

¡ª

25

¡ª

M¦¸

PGA = 1, 2, 4, 8

12

¡ª

¡ª

Bits

DR = 240 SPS

14

¡ª

¡ª

Bits

DR = 60 SPS

16

¡ª

¡ª

Bits

DR = 15 SPS

DR = 3.75 SPS

(Note 1)

System Performance

Resolution and No Missing

Codes

(Effective Number of Bits)

(Note 3)

Data Rate

(Note 4)

18

¡ª

¡ª

Bits

176

240

328

SPS

12 bits mode

44

60

82

SPS

14 bits mode

11

15

20.5

SPS

16 bits mode

2.75

3.75

5.1

SPS

18 bits mode

¡ª

1.5

¡ª

?VRMS

TA = +25¡ãC, DR = 3.75 SPS,

PGA = 1, VIN+ = VIN- = GND

INL

¡ª

10

35

ppm of

FSR

DR = 3.75 SPS, FSR = Full

Scale Range (Note 5)

VREF

¡ª

2.048

¡ª

V

¡ª

0.05

0.35

%

DR

Output Noise

Integral Non-Linearity

Internal Reference Voltage

Gain Error (Note 6)

PGA = 1, DR = 3.75 SPS

Note 1:

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 VREF.

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

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