18-Bit ADC with I2C Interface and Onboard Reference DS

1 2009 Microchip Technology 1 MCP3426/7/8 Features 16-bit ADC with Differential Inputs:- 2 channels: MCP3426 and MCP3427- 4 channels: MCP3428 Differential Input Full Scale Range: -VREF to +VREF Self Calibration of Internal Offset and Gain per Each Conversion On-Board Voltage Reference (VREF):- Accuracy: 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 (VDD= 3V): - Continuous Conversion: 135 A typical - One-Shot Conversion with 1 SPS: - 9 A typical for 16 bit mode- A typical for 14 bit mode- A typical for 12 bit mode On-Board Oscillator I2C Interface : - Standard, Fast and High Speed Modes- User configurable two external address selection pins for MCP3427 and MCP3428 Single Supply Operation: to Extended Temperature Range.

2 -40 C to +125 CTypical 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 EquipmentDescriptionThe MCP3426, MCP3427 and MCP3428 devices(MCP3426/7/8) are the low noise and high accuracy16 Bit Delta- sigma Analog-to-Digital ( A/D) Con-verter family members of the MCP342X series fromMicrochip Technology Inc. These devices can convertanalog inputs to digital codes with up to 16 bits of MCP3426 and MCP3427 devices have twodifferential input channels and the MCP3428 has fourdifferential input channels. All electrical properties ofthese three devices are the same except thedifferences in the number of input channels and I2 Caddress bit selection options.

3 These devices can output analog-to-digital conversionresults at rates of 15 (16-bit mode), 60 (14-bit mode), or240 (12-bit mode) samples per second depending onthe user controllable configuration bit settings using thetwo-wire I2C serial Interface . During each conversion,the device calibrates offset and gain errorsautomatically. This provides accurate conversionresults from conversion to conversion over variations intemperature and power supply device has an on-board Reference voltage,which enables an input range of differentially(full scale range = ). The user can select the gain of the on-boardprogrammable gain amplifier (PGA) using theconfiguration register bits (gain of x1, x2, x4, or x8).This allows the MCP3426/7/8 devices to convert a veryweak input signal with high MCP3426/7/8 devices have two conversionmodes: (a) One-Shot Conversion mode and(b) Continuous Conversion mode.

4 In the One-Shotconversion mode, the device performs a singleconversion and enters a low current standby(shutdown) mode automatically until it receives anotherconversion command. This reduces currentconsumption greatly during idle periods. In continuousconversion mode, the conversion takes placecontinuously at the configured conversion speed. Thedevice updates its output buffer with the most recentconversion devices operate from a single to powersupply and have a two-wire I2C compatible serialinterface for a standard (100 kHz), fast (400 kHz), orhigh-speed ( MHz) , Multi-Channel Analog-to-Digital Converter with I2C Interface and On-Board ReferenceMCP3426/7/8DS22226A-page 2 2009 Microchip Technology I2C address bits for the MCP3427 and MCP3428are selected by using two external I2C addressselection pins (Adr0 and Adr1).

5 The user can configurethe device to one of eight available addresses byconnecting these two address selection pins to VDD,VSS or float. The I2C address bits of the MCP3426 areprogrammed at the factory during production. The MCP3426 is available in 8-pin SOIC, DFN, andMSOP packages. The MCP3427 is available in 10-pinDFN, and MSOP packages. The MCP3428 is availablein 14-pin SOIC and TSSOP TypesMCP3426 Functional Block Diagram 4569CH2- VSSCH3+Adr1 Adr0312CH2+CH3-213CH1-CH4+114CH1+CH4-78 SDASCL VDDMCP34281110 SOIC, TSSOP234789CH1-VDDSDAAdr0 VSSSCL110CH1+Adr156CH2-CH2+MCP3427234567 CH1-VDDSDACH2+VSSSCL18CH1+CH2-MCP3426 MSOP, SOICMSOPMCP34262x3 DFN *VDDCH1-SDACH2+VSS12348765 SCLCH2-CH1+* Includes Exposed Thermal Pad (EP); see Table DFN *VSSCH1-CH2+Adr0 SCL123410987 SDAAdr1CH1+EP11CH2-56 VDDVSSVDDPGASCLSDAMUXI2 CInterfaceGain = 1, 2, 4, or 8 Voltage ReferenceClock( )VREF ADCC onverterOscillatorMCP3426CH1+CH1-CH2+CH2 - 2009 Microchip Technology 3 MCP3426/7/8 MCP3427 Functional Block Diagram MCP3428 Functional Block Diagram VSSVDDCH1+CH1-PGASCLSDAMUXI2 CInterfaceGain = 1, 2, 4, or 8 Adr1 Adr0CH2+CH2-Voltage ReferenceClock( )VREF ADCC onverterOscillatorMCP3427 VSSVDDCH1+CH1-PGASCLSDAMUXI2 CInterfaceGain = 1, 2, 4, or 8 Adr1 Adr0CH2+CH2-CH3+CH3-CH4+CH4-Voltage ReferenceClock( )VREF ADCC onverterOscillatorMCP3428 MCP3426/7/8DS22226A-page 4 2009 Microchip Technology : 2009 Microchip Technology 5 MCP3426/7 CHARACTERISTICSA bsolute Maximum Ratings inputs and outputs.

6 VSS to VDD+ Input Voltage .. |VDD - VSS|Output Short Circuit Current .. ContinuousCurrent at Input Pins .. 2 mACurrent at Output and Supply Pins .. 10 mAStorage Temperature ..-65 C to +150 CAmbient Temp. with power applied ..-55 C to +125 CESD protection on all pins .. 6kV HBM, 400V MMMaximum Junction Temperature (TJ) ..+150 C Notice: Stresses above those listed under Maximum Rat-ings may cause permanent damage to the device. This is astress rating only and functional operation of the device atthose or any other conditions above those indicated in theoperational listings of this specification is not to maximum rating conditions for extended periodsmay affect device CHARACTERISTICSE lectrical Specifications: Unless otherwise specified, all parameters apply for TA = -40 C to +85 C, VDD = + , VSS = 0V,CHn+ = CHn- = VREF/2, VINCOM = VREF /2.

7 All ppm units use 2*VREF as differential full scale Min Typ MaxUnits ConditionsAnalog Inputs Differential Full Scale Input Voltage RangeFSR VVIN = [CHn+ - CHn-]Maximum Input Voltage VDD+ (Note 1)Differential Input Impedance ZIND (f) M During normal mode operation(Note 2)Common Mode input ImpedanceZINC (f) 25 M PGA = 1, 2, 4, 8 System PerformanceResolution and No Missing Codes (Effective Number of Bits)(Note 3)12 BitsDR = 240 SPS14 BitsDR = 60 SPS16 BitsDR = 15 SPSData Rate (Note 4)DR176240328 SPS12 bits mode446082 SPS14 bits bits modeOutput Noise VRMSTA = +25 C, DR =15 SPS, PGA = 1, VIN+ = VIN- = GND Integral Non-LinearityINL 10 ppm of FSRDR = 15 SPS(Note 5)Internal Reference VoltageVREF VGain Error (Note 6) %PGA = 1, DR = 15 SPSPGA Gain Error Match (Note 6) %Between any 2 PGA settingsGain Error Drift (Note 6) 15 ppm/ CPGA=1, DR=15 SPSNote 1:Any input voltage below or greater than this voltage causes leakage current through the ESD diodes at the input parameter is ensured by characterization and not 100% :This input impedance is due to pF internal input sampling capacitor.

8 3:This parameter is ensured by design and not 100% :The total conversion speed includes auto-calibration of offset and :INL is the difference between the endpoints line and the measured code at the center of the quantization :Includes all errors from on-board PGA and :This parameter is ensured by characterization and not 100% :MCP3427 and MCP3428 only. 9:Addr_Float voltage is applied at address :No voltage is applied at address pin (left floating ).MCP3426/7/8DS22226A-page 6 2009 Microchip Technology ErrorVOS 30 VPGA = 1DR = 15 SPSO ffset Drift vs. Temperature 50 nV/ CCommon-Mode Rejection 105 dBat DC and PGA =1, 110 dBat DC and PGA =8, TA = +25 CGain vs. VDD 5 ppm/VTA = +25 C, VDD = to ,PGA = 1 Power Supply Rejection at DC Input 100 dBTA = +25 C, VDD = to ,PGA = 1 Power RequirementsVoltage Current during ConversionIDDA 145180 AVDD = 135 AVDD = Current during Standby ModeIDDS 1 AVDD = Digital Inputs and Digital OutputsHigh level input VDDVat SDA and SCL pinsLow level input voltageVIL SDA and SCL pinsLow level output voltageVOL = 3 mAHysteresis of Schmidt Trigger for inputs (Note 7) VfSCL = 100 kHzSupply Current when I2C bus line is activeIDDB 10 ADevice is in standby mode while I2C bus is activeInput Leakage CurrentIILH 1 AVIH = AVIL = GNDL ogic Status of I2C Address Pins (Note 8)

9 Adr0 and Adr1 PinsAddr_LowVSS device reads logic and Adr1 VDDVThe device reads logic and Adr1 PinsAddr_Float pin voltage if voltage is applied to the address pin. (Note 9) VDD/2 Device outputs float output voltage (VDD/2) on the address pin, if left floating . (Note 10)Pin Capacitance and I2C Bus CapacitancePin capacitance CPIN 4 10pFI2C Bus CapacitanceCb 400pFELECTRICAL CHARACTERISTICS (CONTINUED)Electrical Specifications: Unless otherwise specified, all parameters apply for TA = -40 C to +85 C, VDD = + , VSS = 0V,CHn+ = CHn- = VREF/2, VINCOM = VREF /2. All ppm units use 2*VREF as differential full scale Min Typ MaxUnits ConditionsNote 1:Any input voltage below or greater than this voltage causes leakage current through the ESD diodes at the input parameter is ensured by characterization and not 100% :This input impedance is due to pF internal input sampling capacitor.

10 3:This parameter is ensured by design and not 100% :The total conversion speed includes auto-calibration of offset and :INL is the difference between the endpoints line and the measured code at the center of the quantization :Includes all errors from on-board PGA and :This parameter is ensured by characterization and not 100% :MCP3427 and MCP3428 only. 9:Addr_Float voltage is applied at address :No voltage is applied at address pin (left floating ). 2009 Microchip Technology 7 MCP3426/7/8 TEMPERATURE CHARACTERISTICSE lectrical Specifications: Unless otherwise indicated, TA = -40 C to +125 C, VDD = + , VSS = RangesSpecified Temperature RangeTA-40 +85 COperating Temperature RangeTA-40 +125 CStorage Temperature RangeTA-65 +150 CThermal Package ResistancesThermal Resistance, 8L-DFN (2x3) JA C/WThermal Resistance, 8L-MSOP JA 211 C/WThermal Resistance, 8L-SOIC JA C/WThermal Resistance, 10L-DFN (3x3) JA 57 C/WThermal Resistance, 10L-MSOP JA 202 C/WThermal Resistance, 14L-SOIC JA 120 C/WThermal Resistance, 14L-TSSOP JA 100 C/WMCP3426/7/8DS22226A-page 8 2009 Microchip Technology : 2009 Microchip Technology 9 MCP3426/7 PERFORMANCE CURVESNote.