INA238

Part: INA238 — Texas Instruments

Type: High-Precision Digital Power Monitor

Description: The INA238 is an ultra-precise 16-bit delta-sigma ADC digital power monitor designed for current-sensing applications, capable of measuring full-scale differential inputs of ±163.84 mV or ±40.96 mV with common-mode voltage support from -0.3 V to +85 V, and features a 2.94-MHz high-speed I2C interface.

Operating Conditions:

• Supply voltage: 2.7 V to 5.5 V
• Operating temperature: -40 to +125 °C
• Common-mode input range: -0.3 V to 85 V

Absolute Maximum Ratings:

• Max supply voltage: 6 V
• Max junction temperature: 150 °C
• Max storage temperature: 150 °C

Key Specs:

• Shunt offset voltage: ±5 μV (maximum, VCM = 48 V or 0 V)
• Shunt offset voltage drift: ±20 nV/°C (maximum, TA = -40°C to +125°C)
• Shunt voltage gain error: ±0.1% (maximum)
• Shunt voltage gain error drift: ±25 ppm/°C (maximum)
• Common-mode rejection: 140 dB (minimum, -0.3 V < VCM < 85 V, TA = -40°C to +125°C)
• Input bias current: 2.5 nA (maximum, VCM = 85 V)
• Power total measurement error (TME): ±0.7% (maximum, TA = -40°C to +125°C, at full scale)
• Quiescent current: 750 μA (maximum, VSENSE = 0 V, TA = 25°C)

Features:

• High-resolution, 16-bit delta-sigma ADC
• Fast alert response: 75 μs
• Wide common-mode range: -0.3 V to +85 V
• Bus voltage sense input: 0 V to 85 V
• Shunt full-scale differential range: ±163.84 mV / ±40.96 mV
• Integrated temperature sensor: ±1°C (maximum at 25°C)
• Programmable conversion time and averaging
• 2.94-MHz high-speed I2C interface with 16 pin-selectable addresses

Applications:

• DC/DC converters and power inverters
• Industrial battery packs
• Power-over-ethernet (PoE)
• Telecom equipment
• Enterprise servers

Package:

• VSSOP (10) - 3.00 mm × 3.00 mm

• High-resolution, 16-bit delta-sigma ADC
• Current monitoring accuracy:
• -Offset voltage: ±5 μV (maximum)
• -Offset drift: ±0.02 μV/°C (maximum)
• -Gain error: ±0.1% (maximum)
• -Gain error drift: ±25 ppm/°C (maximum)
• -Common mode rejection: 140 dB (minimum)
• Power monitoring accuracy:
• -0.7% full scale, -40°C to +125°C (maximum)
• Fast alert response: 75 μs
• Wide common-mode range: -0.3 V to +85 V
• Bus voltage sense input: 0 V to 85 V
• Shunt full-scale differential range:
• ±163.84 mV / ±40.96 mV
• Input bias current: 2.5 nA (maximum)
• Temperature sensor: ±1°C (maximum at 25°C)
• Programmable conversion time and averaging
• 2.94-MHz high-speed I 2 C interface with 16 pinselectable addresses
• Operates from a 2.7-V to 5.5-V supply:
• -Operational current: 640 μA (typical)
• -Shutdown current: 5 μA (maximum)

• DC/DC converters and power inverters
• Industrial battery packs
• Power-over-ethernet (PoE)
• Telecom equipment
• Enterprise servers

Figure 5-1. DGS Package 10-Pin VSSOP Top View

Table 5-1. Pin Functions

at T A = 25 °C, V S = 3.3 V, V SENSE = VIN+ - VIN- = 0 V, V CM = V IN- = 48 V (unless otherwise noted)

over operating free-air temperature range (unless otherwise noted) (1)

• (2) VIN+ and VIN- are the voltages at the IN+ and IN- pins, respectively.

over operating free-air temperature range (unless otherwise noted)

The low offset voltage and low input bias current of the INA238 allow accurate monitoring of a wide range of currents. To accurately monitor currents with high resolution, select the value of the shunt resistor so that the resulting sense voltage is close to the maximum allowable differential input voltage range (either ±163.84 mV or ±40.96 mV, depending on register settings). The circuit for monitoring currents in a high-side configuration is shown in Figure 8-2.

Figure 8-2. INA238 High-Side Sensing Application Diagram