Document
DA6502.008 29 November 2012
MAS6502
Piezoresistive Sensor Signal Interface IC
• Optimized for Piezoresistive Pressure Sensors
• Very Low Power Consumption • Ratiometric 16 Bit ∆Σ ADC • Linearity 14 Bits • Internal Clock Oscillator • Serial Data Interface (I2C® Bus) • 256 Bit EEPROM Memory
DESCRIPTION
MAS6502 is a 16 bit Analog-to-Digital Converter (ADC), which employs a delta-sigma (∆Σ) conversion technique. With the linear input signal range of 260 mVPP the linearity is 14 bits.
MAS6502 is designed especially to meet the requirement for low power consumption, thus making it an ideal choice for battery powered systems. The MAS6502 is equipped with a standby function, i.e. the ADC is in power down between each conversion. By utilizing this and overall low power consumption, current consumption values of 2.5 µA (one pressure conversion in a second with full 14-bit accuracy) or less can be achieved.
MAS6502 has an on-chip second order decimator filter to process the output of the second order ∆Σ -modulator. The ADC also has four
selectable input signal ranges with one optional offset level. An internal trimmed clock oscillator provides a system clock signal (DCLK) eliminating the need for an external clock signal.
A bi-directional I2C® bus compatible 2-wire serial bus is used for configuring conversion parameters, starting conversion and reading out the A/D conversion result.
MAS6502 has one input channel suitable for a piezoresistive pressure sensor. In addition to pressure measurement the device can be configured also for temperature measurement.
The 256-bit EEPROM memory is available for storing trimming and calibration data on chip.
FEATURES
APPLICATIONS
• Low Standby Current Consumption 0.05 µA Typ
• Calibrated Piezoresistive Pressure Modules
• Very Low Supply Current: 0.4 µA…2.5 µA Typ
• Temperature measurement
• Supply Voltage: 2.0 V…3.6 V
• Battery Powered Systems
• Ratiometric ∆Σ Conversion
• Low Frequency Measurement Applications
• Selectable Input Signal Ranges (VDD=2.35V):
• Current/Power Consumption Critical Systems
325 mVPP, 220 mVPP, 150 mVPP, 100 mVPP
• Industrial and Process Control Applications in
• Selectable Optional Offset (VDD=2.35V):
Noisy Environments
33 mV
Selectable Sensor Resistance Values
5 kΩ, 4.5 kΩ, 4 kΩ, 3.4 kΩ
• Over Sampling Ratio: 512, 256, 128, 64
• Internal System Clock Signal 100 kHz
• Conversion Times 0.8 ms…10.6 ms Typ • 2-Wire Serial Data Interface (I2C® Bus)
• 256 Bit EEPROM Memory
• Good Noise Performance due to ∆Σ
Architecture
I2C is a registered trademark of NXP.
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DA6502.008 29 November 2012
BLOCK DIAGRAM
VDD
PI NI COMMON
R3
P T
P VDD T
R1
VREFP
TE3 OSC
EEPROM
ADC
CONTROL
I2C
SDA SCL
VREFN
XCLR EOC
R4
PT
R2
T
GND
MAS6502
TEST
TE1 TE2
Figure 1. MAS6502 block diagram
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol
Conditions
All Voltages with Respect to Ground
Min Max Unit
Supply Voltage
VDD
-0.3 5.0 V
Voltage Range for All Pins
-0.3 VIN + 0.3 V
Latchup Current Limit
ILUT For all pins, test according to -100 JESD78A.
+100
mA
Junction Temperature
TJmax
+ 150
°C
Storage Temperature
TS
Note 1
- 55
+125
°C
Note 1. See EEPROM memory data retention at hot temperature. Storage or bake at hot temperatures will reduce the wafer level trimming and calibration data retention time. Note: The absolute maximum rating values are stress ratings only. Functional operation of the device at conditions between maximum operating conditions and absolute maximum ratings is not implied and EEPROM contents may be corrupted. Exposure to these conditions for extended periods may affect device reliability (e.g. hot carrier degradation, oxide breakdown). Applying conditions above absolute maximum ratings may be destructive to the devices. Note: This is a CMOS device and therefore it should be handled carefully to avoid any damage by static voltages (ESD).
RECOMMENDED OPERATION CONDITIONS
Parameter
Symbol
Conditions
Min Typ Max Unit
Supply Voltage
VDD
2.0 2.35 3.6
V
Supply Voltage at EEPROM Programming
VDD
T=+25°C. Note 1.
3.0 3.3 3.6
V
Operating Temperature
TA
-40 +25 +85
°C
The device performance may deteriorate in the long run if the Recommended Operation Conditions limits are continuously exceeded. Note 1. It is recommended to program the EEPROM at room temperature.
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DA6502.008 29 November 2012
ELECTRICAL CHARACTERISTICS
TA = -40oC to +85oC, VDD = 2.0V to 3.6V, Typ TA = 27oC, Typ VDD = 2.35 V, Rsensor = 4.5kΩ unless otherwise noted
Parameter
Symbol
Conditions
Min Typ Max Unit
Average ADC Current during Conversion Time
ICONV
Pressure mode Temperature mode
80 185 330 100 200 350
Average ADC Current in Pressure Measurement
IADC_P 1 conversion/s, Rsensor = 4.5 kΩ,
OSR=512
0.4 1.0 1.7
during Conversion Period
OSR=256
0.2 0.5 0.9
(no sensor current
OSR=128
0.1 0.3 0.5
included)
OSR=64
0.06 0.15 0.26
Average ADC Current in
IADC_T 1 conversion/s, Rsensor = 4.5 kΩ,
Temperatur.