Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsPMIC - current control/management Current monitoring VSSOP 10

Power Register

Current Register

I C

Interface

Voltage Register

INA226

GND

BUS

ADC

Alert

SDA

SCL

0.1 F

BYPASS

High-

Side

Shunt

Low-

Side

Shunt

Load

Alert Register

(Supply Voltage)

Power Supply

(0V to 36V)

INA226

www.ti.com

SBOS547 –JUNE 2011

High-or Low-Side Measurement,

Bi-Directional CURRENT/POWER MONITOR with I

C™ Interface

Check for Samples: INA226

FEATURES

DESCRIPTION

The INA226 is a current shunt and power monitor

• SENSES BUS VOLTAGES FROM 0V TO +36V

with an I

C interface. The INA226 monitors both a

• HIGH- OR LOW-SIDE SENSING

shunt voltage drop and bus supply voltage.

• REPORTS CURRENT, VOLTAGE, AND POWER

Programmable calibration value, conversion times,

• HIGH ACCURACY:

and averaging, combined with an internal multiplier,

enable direct readouts of current in amperes and

– 0.1% Gain Error (Max)

power in watts.

– 10μV Offset (Max)

• CONFIGURABLE AVERAGING OPTIONS

The INA226 senses current on buses that can vary

from 0V to +36V, while the device obtains its power

• 16 PROGRAMMABLE ADDRESSES

from a single +2.7V to +5.5V supply, drawing a

• OPERATES FROM 2.7 to 5.5V POWER SUPPLY

typical of 330μA of supply current. The INA226 is

• MSOP-10 PACKAGE

specified over the operating temperature range

of –40°C to +125°C. The I

C interface features 16

APPLICATIONS

programmable addresses.

• SERVERS

Summary of content (33 pages)

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INA226 SBOS547 – JUNE 2011 www.ti.com High-or Low-Side Measurement, Bi-Directional CURRENT/POWER MONITOR with I2C™ Interface Check for Samples: INA226 FEATURES DESCRIPTION • • • • The INA226 is a current shunt and power monitor with an I2C interface. The INA226 monitors both a shunt voltage drop and bus supply voltage. Programmable calibration value, conversion times, and averaging, combined with an internal multiplier, enable direct readouts of current in amperes and power in watts.
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INA226 SBOS547 – JUNE 2011 www.ti.com This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with appropriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure.
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INA226 SBOS547 – JUNE 2011 www.ti.com ELECTRICAL CHARACTERISTICS: VS = +3.3V Boldface limits apply over the specified temperature range, TA = –40°C to +125°C. At TA = +25°C, VIN+ = 12V, VSENSE = (VIN+ – VIN–) = 0mV, VBUS = 12V, unless otherwise noted. INA226 PARAMETER CONDITIONS MIN TYP MAX UNIT INPUT Shunt voltage input range -81.9175 81.
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INA226 SBOS547 – JUNE 2011 www.ti.com ELECTRICAL CHARACTERISTICS: VS = +3.3V (continued) Boldface limits apply over the specified temperature range, TA = –40°C to +125°C. At TA = +25°C, VIN+ = 12V, VSENSE = (VIN+ – VIN–) = 0mV, VBUS = 12V, unless otherwise noted. INA226 PARAMETER CONDITIONS MIN TYP MAX UNIT POWER SUPPLY Operating supply range +5.5 V Quiescent current +2.7 330 420 μA Quiescent current, power-down mode 0.
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INA226 SBOS547 – JUNE 2011 www.ti.com PIN CONFIGURATIONS DGS PACKAGE MSOP-10 (Top View) A1 1 10 VIN+ A0 2 9 VIN- Alert 3 8 VBUS SDA 4 7 GND SCL 5 6 VS+ PIN DESCRIPTIONS MSOP-10 (DGS) PIN NO NAME 1 A1 Address pin. Connect to GND, SCL, SDA, or VS. Table 7 shows pin settings and corresponding addresses. DESCRIPTION 2 A0 Address pin. Connect to GND, SCL, SDA, or VS. Table 7 shows pin settings and corresponding addresses. 3 Alert Multi-functional alert, open-drain output.
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INA226 SBOS547 – JUNE 2011 www.ti.com TYPICAL CHARACTERISTICS At TA = +25°C, VS = +3.3V, VIN+ = 12V, VSENSE = (VIN+ – VIN–) = 0mV, VBUS = 12V, unless otherwise noted. SHUNT INPUT OFFSET VOLTAGE PRODUCTION DISTRIBUTION FREQUENCY RESPONSE 0 −10 Population Gain (dB) −20 −30 −40 G001 10 8 6 4 Input Offset Voltage (mV) Figure 2. Figure 3. SHUNT INPUT OFFSET VOLTAGE vs TEMPERATURE SHUNT INPUT COMMON-MODE REJECTION RATIO vs TEMPERATURE −1 Common−Mode Rejection Ratio (dB) 170 −1.2 −1.
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INA226 SBOS547 – JUNE 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = +25°C, VS = +3.3V, VIN+ = 12V, VSENSE = (VIN+ – VIN–) = 0mV, VBUS = 12V, unless otherwise noted. SHUNT INPUT GAIN ERROR vs COMMON-MODE VOLTAGE BUS INPUT OFFSET VOLTAGE PRODUCTION DISTRIBUTION 300 200 Population Gain Error (m%) 250 150 100 50 G008 7.5 6 4.5 3 1.5 36 0 32 -1.5 8 12 16 20 24 28 Common−Mode Input Voltage (V) -3 4 -4.5 0 -7.5 −50 -6 0 Input Offset Voltage (mV) Figure 8. Figure 9.
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INA226 SBOS547 – JUNE 2011 www.ti.com TYPICAL CHARACTERISTICS (continued) At TA = +25°C, VS = +3.3V, VIN+ = 12V, VSENSE = (VIN+ – VIN–) = 0mV, VBUS = 12V, unless otherwise noted. INPUT BIAS CURRENT vs TEMPERATURE INPUT BIAS CURRENT vs TEMPERATURE, SHUTDOWN 260 Input Bias Current − Shutdown (nA) Input Bias Current (µA) 24 22 20 18 16 −50 −25 0 25 50 Temperature (°C) 75 100 220 180 140 100 60 20 −50 125 −25 0 G013 Figure 14.
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INA226 SBOS547 – JUNE 2011 www.ti.com APPLICATION INFORMATION The INA226 is a digital current shunt monitor with an I2C- and SMBus-compatible interface. It provides digital current, voltage, and power readings necessary for accurate decision-making in precisely-controlled systems. Programmable registers allow flexible configuration for measurement resolution as well as continuous-versus-triggered operation. Detailed register information appears at the end of this data sheet, beginning with Table 2.
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INA226 SBOS547 – JUNE 2011 www.ti.com Although the INA226 can be read at any time, and the data from the last conversion remain available, the Conversion Ready Flag bit (Mask/Enable Register, CVRF bit) is provided to help coordinate one-shot or triggered conversions. The Conversion Ready Flag bit is set after all conversions, averaging, and multiplication operations are complete. The Conversion Ready Flag bit clears under these conditions: 1.
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INA226 SBOS547 – JUNE 2011 www.ti.com Averaging and Conversion Time Considerations The INA226 has programmable conversion times for both the shunt voltage and bus voltage measurements. The conversion times for these measurements can be selected from as fast as 140μs to as long as 8.244ms. The conversion time settings, along with the programmable averaging mode, allow the INA226 to be configured to optimize the available timing requirements in a given application.
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INA226 SBOS547 – JUNE 2011 www.ti.com Filtering and Input Considerations Measuring current is often noisy, and such noise can be difficult to define. The INA226 offers several options for filtering by allowing the conversion times and number of averages to be selected independently in the Configuration Register. The conversion times can be set independently for the shunt voltage and bus voltage measurements to allow added flexibility in configuring the monitoring of the power-supply bus.
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INA226 SBOS547 – JUNE 2011 www.ti.com ALERT PIN The INA226 has a single Alert Limit register, 07h, that allows the Alert pin to be programmed to respond to a single user-defined event or to a conversion ready notification if desired. The Mask/Enable Register allows the user to select from one of the five available functions to monitor and/or set the conversion ready bit to control the response of the Alert pin.
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INA226 SBOS547 – JUNE 2011 www.ti.com PROGRAMMING THE INA226 An important aspect of the INA226 is that it does not necessarily measure current or power. The INA226 measures both the differential voltage applied between the VIN+ and VIN- input pins and the voltage applied to the VBUS pin.
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INA226 SBOS547 – JUNE 2011 www.ti.com CONFIGURE/MEASURE/CALCULATE EXAMPLE In this example, shown in Figure 23, a nominal 10A load creates a differential voltage of 20mV across a 2mΩ shunt resistor. The bus voltage for the INA226 is measured at the external VBUS input pin, which in this example is connected to the VIN– pin to measure the voltage level delivered to the load. For this example, the VBUS pin measures less than 12V because the voltage at the VIN– pin is 11.
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INA226 SBOS547 – JUNE 2011 www.ti.com The Power Register (03h) is then be calculated by multiplying the decimal value of the Current Register, 10000, by the decimal value of the Bus Voltage Register, 9584, and then dividing by 20,000, as defined in Equation 4. For this example, the result for the Power Register is 12B8h, or a decimal equivalent of 4792. Multiplying this result by the power LSB (25 times the [1 × 10–3 Current LSB]) results in a power calculation of (4792 × 25mW/bit), or 119.82W.
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INA226 SBOS547 – JUNE 2011 www.ti.com Simple Current Shunt Monitor Usage (No Programming Necessary) The INA226 can be used without any programming if it is only necessary to read a shunt voltage drop and bus voltage with the default power-on reset configuration and continuous conversion of shunt and bus voltage.
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INA226 SBOS547 – JUNE 2011 www.ti.com REGISTER DETAILS All 16-bit INA226 registers are two 8-bit bytes via the I2C interface. Configuration Register 00h (Read/Write) BIT # D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 BIT NAME RST — — — AVG2 AVG1 AVG0 VBUSCT2 VBUSCT1 VBUSCT0 VSHCT2 VSHCT1 VSHCT0 MODE3 MODE2 MODE1 POR VALUE 0 1 0 0 0 0 0 1 0 0 1 0 0 1 1 1 The Configuration Register settings control the operating modes for the INA226.
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INA226 SBOS547 – JUNE 2011 www.ti.com VBUS CT: Bus Voltage Conversion Time Bits 6–8 Sets the conversion time for the bus voltage measurement. Table 4 shows the VBUS CT bit options and related conversion times for each bit. Table 4. VBUS CT Bit Settings [8:6] (1) (1) VBUS CT2 D8 VBUS CT1 D7 VBUS CT0 D6 CONVERSION TIME 0 0 0 140µs 0 0 1 204µs 0 1 0 332µs 0 1 1 588µs 1 0 0 1.1ms 1 0 1 2.116ms 1 1 0 4.156ms 1 1 1 8.244ms Shaded values are default.
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INA226 SBOS547 – JUNE 2011 www.ti.com DATA OUTPUT REGISTERS Shunt Voltage Register 01h (Read-Only) The Shunt Voltage Register stores the current shunt voltage reading, VSHUNT. Negative numbers are represented in twos complement format. Generate the twos complement of a negative number by complementing the absolute value binary number and adding 1. Extend the sign, denoting a negative number by setting the MSB = '1'. Example: For a value of VSHUNT = –80mV: 1. Take the absolute value: 80mV 2.
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INA226 SBOS547 – JUNE 2011 www.ti.com Current Register 04h (Read-Only) If averaging is enabled, this register displays the averaged value.
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INA226 SBOS547 – JUNE 2011 www.ti.com AFF: Alert Function Flag Bit 4 While only one Alert Function can be monitored at the Alert pin at a time, the Conversion Ready can also be enabled to assert the Alert pin. Reading the Alert Function Flag following an alert allows the user to determine if the Alert Function was the source of the Alert. When the Alert Latch Enable bit is set to Latch mode, the Alert Function Flag clears only when the Mask/Enable Register is read.
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INA226 SBOS547 – JUNE 2011 www.ti.com Data transfer is then initiated and eight bits of data are sent, followed by an Acknowledge bit. During data transfer, SDA must remain stable while SCL is high. Any change in SDA while SCL is high is interpreted as a start or stop condition. Once all data have been transferred, the master generates a stop condition, indicated by pulling SDA from low to high while SCL is high. The INA226 includes a 28ms timeout on its interface to prevent locking up the bus.
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INA226 SBOS547 – JUNE 2011 www.ti.com WRITING TO/READING FROM THE INA226 Accessing a specific register on the INA226 is accomplished by writing the appropriate value to the register pointer. Refer to Table 2 for a complete list of registers and corresponding addresses. The value for the register pointer (as shown in Figure 27) is the first byte transferred after the slave address byte with the R/W bit low. Every write operation to the INA226 requires a value for the register pointer.
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INA226 SBOS547 – JUNE 2011 www.ti.com Figure 26 shows the timing diagram for the SMBus Alert response operation. Figure 27 illustrates a typical register pointer configuration. ALERT 1 9 1 9 SCL SDA 0 0 0 1 1 0 0 R/W Start By Master 1 0 0 A2 ACK By INA226 A1 A0 0 From INA226 Frame 1 SMBus ALERT Response Address Byte (1) A3 Frame 2 Slave Address Byte NACK By Master Stop By Master (1) The value of the Slave Address Byte is determined by the settings of the A0 and A1 pins.
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INA226 SBOS547 – JUNE 2011 www.ti.com High-Speed I2C Mode When the bus is idle, both the SDA and SCL lines are pulled high by the pull-up devices. The master generates a start condition followed by a valid serial byte containing High-Speed (HS) master code 00001XXX. This transmission is made in fast (400kHz) or standard (100kHz) (F/S) mode at no more than 400kHz. The INA226 does not acknowledge the HS master code, but does recognize it and switches its internal filters to support 3.4MHz operation.
PAGE 27
INA226 SBOS547 – JUNE 2011 www.ti.com SMBus Alert Response The INA226 is designed to respond to the SMBus Alert Response address. The SMBus Alert Response provides a quick fault identification for simple slave devices. When an Alert occurs, the master can broadcast the Alert Response slave address (0001 100) with the Read/Write bit set high.
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE MATERIALS INFORMATION www.ti.com 19-Nov-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant INA226AIDGSR VSSOP DGS 10 2500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 INA226AIDGST VSSOP DGS 10 250 330.0 12.4 5.3 3.4 1.4 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 19-Nov-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) INA226AIDGSR VSSOP DGS 10 2500 366.0 364.0 50.0 INA226AIDGST VSSOP DGS 10 250 366.0 364.0 50.
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IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. Buyers should obtain the latest relevant information before placing orders and should verify that such information is current and complete.