Low-Cost, SC70, Voltage-Output, High-Side Current-Sense Amplifier# Technical Documentation: MAX4073HAXKT High-Side Current-Sense Amplifier
Manufacturer : MAXIM (now part of Analog Devices)
Component : MAX4073HAXKT
Description : Precision, High-Side Current-Sense Amplifier with Voltage Output
Package : 6-SC70 (SOT-363)
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## 1. Application Scenarios
### Typical Use Cases
The MAX4073HAXKT is a precision, high-side current-sense amplifier designed to monitor current flow by measuring the voltage drop across a shunt resistor placed in series with the power rail. Its primary function is to convert a small differential voltage (developed across the shunt) into a ground-referenced, amplified output voltage suitable for analog-to-digital converters (ADCs) or monitoring circuitry.
Key Operational Use Cases Include:
* Battery Charge/Discharge Monitoring: Accurately measuring current flowing into (charging) and out of (discharging) battery packs in portable devices, power tools, and energy storage systems. This enables state-of-charge (SoC) estimation and protection circuitry.
* Power Supply Load Monitoring: Providing real-time feedback on the current drawn by subsystems (e.g., processors, motor drives) in servers, telecom equipment, and industrial controllers. This facilitates load balancing, fault detection, and thermal management.
* Overcurrent Protection and Fusing: Continuously sensing current to trigger safety shutdowns or alarms in motor control units, power distribution boards, and automotive electronic control units (ECUs) before damage occurs.
* 4-20mA Loop Transmitter Systems: Serving as a precise receiver to measure the loop current in industrial process control instrumentation.
### Industry Applications
* Consumer Electronics: Smartphones, tablets, laptops for battery management and USB power delivery (USB-PD) monitoring.
* Telecommunications & Networking: Base stations, routers, and switches for monitoring board-level power consumption and health of point-of-load (POL) converters.
* Industrial Automation: Programmable Logic Controllers (PLCs), servo drives, and robotics for motor current feedback and system diagnostics.
* Automotive: Battery management systems (BMS) in electric/hybrid vehicles, infotainment systems, and advanced driver-assistance systems (ADAS) for power monitoring.
* Test & Measurement Equipment: Precision power supplies and electronic loads for current readback functionality.
### Practical Advantages and Limitations
Advantages:
* High-Side Sensing: Allows monitoring without interrupting the ground path, which is critical for systems with multiple grounds or where ground disturbances must be minimized.
* Wide Common-Mode Range: Operates with a common-mode voltage (`VCM`) from +0.3V to +28V, independent of the supply voltage (`VCC`), making it suitable for 12V, 24V, and other common industrial/automotive rails.
* Low Input Offset Voltage: Typically ±100µV (MAX4073H grade), which minimizes error when measuring small voltage drops across low-value shunt resistors, improving accuracy.
* Small Form Factor: The SC-70 package is ideal for space-constrained applications.
* Fixed Gain Options: The MAX4073HAXKT has a fixed gain of 20 V/V, simplifying design by eliminating external gain-setting resistors and their associated tolerance/TC errors.
Limitations:
* Fixed Gain: The specific variant (H = 20 V/V) offers less flexibility compared to programmable-gain amplifiers. Other gain versions (e.g., MAX4073T: 60 V/V, MAX4073F: 100 V/V) must be selected for different sensing ranges.
* Bandwidth: The gain-bandwidth product is limited (typ. 250kHz for G=20). This is sufficient for
