INA238

Part: INA238AIDGSR — Texas Instruments

Type: Digital Power Monitor / Current Sense Amplifier (I²C)

Description: 85 V common-mode, 16-bit delta-sigma ADC power monitor with I²C interface, ±5 μV max offset, ±0.1% max gain error, and an integrated ±1 °C temperature sensor, powered from 2.7–5.5 V.

Operating Conditions:

• Supply voltage (VS): 2.7–5.5 V
• Operating temperature: -40 to +125 °C (ambient)
• Common-mode input range: -0.3 to +85 V
• I²C clock: up to 400 kHz (fast mode), up to 2.94 MHz (high-speed mode)

Absolute Maximum Ratings:

• Max supply voltage: 6 V
• Differential input (VIN+ − VIN−): ±40 V
• Common-mode and VBUS: -0.3 to 85 V
• Input current into any pin: 5 mA
• Max junction temperature: 150 °C
• Storage temperature: -65 to 150 °C

Key Specs:

• Shunt offset voltage: ±1.5 μV typ, ±5 μV max (VCM = 48 V, TA = 25 °C); drift ±20 nV/°C max
• Shunt and VBUS gain error: ±0.01% typ, ±0.1% max; gain error drift ±25 ppm/°C max
• Power total measurement error: ±0.7% max at full scale (-40 to +125 °C)
• CMRR: 140 dB min, 160 dB typ (-0.3 V < VCM < 85 V, -40 to +125 °C)
• Input bias current: 2.5 nA max (VCM = 85 V)
• Shunt full-scale range: ±163.84 mV (ADCRANGE = 0) or ±40.96 mV (ADCRANGE = 1)
• Temperature sensor accuracy: ±1 °C max at 25 °C; ±2 °C max over -40 to +125 °C
• Quiescent current: 640 μA typ, 750 μA max (25 °C); 1.1 mA max over -40 to +125 °C
• Shutdown current: 2.8 μA typ, 5 μA max
• ADC conversion time: 50 μs to 4120 μs; VBUS input impedance 1 MΩ typ

Features:

• 16-bit delta-sigma ADC
• Reports current, bus voltage, temperature, and power
• Fast alert response: 75 μs
• Bus voltage sense input: 0 to 85 V
• Programmable conversion time and sample averaging (1x to 1024x)
• 2.94 MHz high-speed I²C interface with 16 pin-selectable addresses
• Open-drain ALERT output

Applications:

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

Package:

• DGS VSSOP, 10 pins (3.00 mm × 4.90 mm)

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

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

Figure 4-1. DGS Package 10-Pin VSSOP Top View

Table 4-1. Pin Functions

at T A = 25 °C, V S = 3.3V, V SENSE = V IN+ - V IN- = 0V, V CM = VIN- = 48V (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 7-2.

Figure 7-2. INA238 High-Side Sensing Application Diagram

• (1) For more information, see Section 10.
• (2) The package size (length × width) is a nominal value and includes pins, where applicable.

Simplified Block Diagram