19-4668; Rev 1; 12/09
Low-Power, Active Energy, Polyphase AFE
MAXQ381
General Description
Features
The MAXQ3181 is a dedicated electricity measurement
front-end that collects and calculates polyphase volt-
age, current, active power and energy, and many other
metering parameters of a polyphase load. The comput-
ed results can be retrieved by an external master
through the on-chip serial peripheral interface (SPI™)
bus. This bus is also used by the external master to
configure the operation of the MAXQ3181 and monitor
the status of operations.
♦ Compatible with 3-Phase/3-Wire, 3-Phase/4-Wire,
and Other 3-Phase Services
♦ 0.1% Active Power and Energy Linearity Error
♦ 0.5% Apparent Power and Energy Linearity Error
♦ 0.5% Linearity Errors for RMS Voltage and RMS
Current
♦ Neutral Line Current Measurement
♦ Line Frequency (Hz)
The MAXQ3181 performs voltage and current measure-
ments using an integrated ADC that can measure up to
seven external differential signal pairs. An eighth differ-
ential signal pair is used to measure the die tempera-
ture. An internal amplifier automatically adjusts the
current channel gain to compensate for low-current
channel-signal levels.
♦ Power Factors
♦ Phase Sequence Indication
♦ Phase Voltage Absence Detection
♦ Programmable Pulse Width
♦ Programmable No-Load Current Threshold
♦ Programmable Meter Constant
Applications
♦ Programmable Thresholds for Undervoltage and
3-Phase Active Energy Electricity Meters
Overvoltage Detection
Ordering Information
♦ Programmable Threshold for Overcurrent Detection
♦ Amp-Hours in Absence of Voltage Signals
♦ On-Chip Digital Temperature Sensor
PART
TEMP RANGE
PIN-PACKAGE
MAXQ3181-RAN+
-40°C to +85°C
28 TSSOP
+Denotes a lead(Pb)-free/RoHS-compliant package.
♦ Precision Internal Voltage Reference 2.048V
(30ppm/°C typical), Also Supports An External
Voltage Reference
Pin Configuration and Typical Application Circuit appear at
end of data sheet.
♦ Active Power and Energy of Each Phase and
Combined 3-Phase (kWh), Positive and Negative
♦ Apparent Power and Energy of Each Phase and
Combined 3-Phase
♦ Supports Software Meter Calibration
♦ Up to 3-Point Multipoint Calibration to
Compensate for Transducer Nonlinearity
♦ Power-Fail Detection
♦ Bidirectional Reset Input/Output
♦ SPI-Compatible Serial Interface with Interrupt
Request (IRQ) Output
♦ Single 3.3V Supply, Low Power (35mW typical)
MAXQ is a registered trademark of Maxim Integrated Products, Inc.
SPI is a trademark of Motorola, Inc.
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be
simultaneously available through various sales channels. For information about device errata, go to: www.maxim-ic.com/errata.
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.