Newsletter Issue 55

Current Sense Amplifier Design Guide and Application Examples

2025/12/26

In modern electronics, precision current monitoring is more than protection as it defines system efficiency and reliability. By selecting the right current sense amplifier, system designers can achieve real-time visibility of power behaviour, allowing effective circuit protection, efficiency optimisation and intelligent remote control across complex systems. Current sense amplifiers are divided into two types:

Digital Type – providing complete voltage, current and power data and supporting I²C and SMBus interfaces, ideal for standby management and data analysis applications.
Analog Type – offering fast response and simple circuitry, well-suited for real-time feedback and protection functions.

To meet diverse design requirements, Richtek offers a comprehensive range of high-precision current sense amplifiers, including digital types RTQ6132 / RTQ6134 / RTQ6136, RTQ6059, RTQ6053 / RTQ6056, and Analog types RTQ6060A/RTQ6060B, RTQ6050/RTQ6052. These devices cover a wide input voltage range and various accuracy levels, helping system designers quickly implement the most suitable power monitoring solutions.

Application Examples

Application	Description
Servers	In data centers, current sense amplifiers play a crucial role in power monitoring, energy optimisation and remote diagnostics. The RTQ6136, designed for 48 V systems, supports up to 75V AMR common-mode voltage, fulfilling high-reliability monitoring requirements.
USB Power Delivery (USB PD)	Accurate current monitoring ensures charging safety and optimised power efficiency. The RTQ6059 offers two address-select pins supporting up to 16 address options, ideal for multi-port PD systems managed by a single embedded controller.
PoE (Power over Ethernet)	Current sensing enables identification of PD type and power demand, allowing dynamic power allocation and preventing overload in multi-PD systems. The RTQ6056, featuring a low-voltage detection function, is placed on the low-side to monitor PoE input and assist system control.
Desktop Computers	Real-time current monitoring enhances performance and reliability while reducing design risk. The RTQ6060 serves as the main power monitoring component, providing rapid current feedback to the embedded controller for instant system adjustment.

Current sense amplifiers have become an integral part of power management and system design. Richtek provides a complete portfolio of current sense amplifiers for more efficient and reliable systems.

See Application Note

Digital CSA

▸ Input Sense Range: Programmable

Product Number	Common Mode Voltage Range	Maximum Offset	Maximum Gain Error
RTQ6136 TWCSP-8P, TSOT-28	0V to 60V	4µV	0.1%
RTQ6134 TWCSP-8P	0V to 60V	80µV	0.5%
RTQ6132 TSOT-28	0V to 60V	40µV	0.3%
RTQ6059 TSOT-23-8, MSOP-10	0V to 32V	50µV	0.3%

▸ Input Sense Range: Fixed

Product Number	Common Mode Voltage Range	Maximum Offset	Maximum Gain Error	Buy Online
RTQ6056 MSOP-10	0V to 36V	10µV	0.12%
RTQ6053 VQFN-16L	0V to 36V	25µV	0.3%

Analog CSA

▸ Available Gain: 50V/V, 75V/V, 100V/V, 200V/V, 500V/V, 1000V/V

Product Number	Common Mode Voltage Range	Maximum Offset	Maximum Gain Error	Buy Online
RTQ6060A SC-70-6	0V to 36V	±35µV~±100µV	±0.4%
RTQ6060B SC-70-6	0V to 36V	±150µV	±0.8%

▸ Available Gain: 100V/V

Product Number	Common Mode Voltage Range	Maximum Offset	Maximum Gain Error	Buy Online
RTQ6052 MSOP-8, SOP-8	2V to 80V	±2.5mV	±2%

▸ Available Gain: 20V/V

Product Number	Common Mode Voltage Range	Maximum Offset	Maximum Gain Error	Buy Online
RTQ6050 MSOP-8, SOP-8	2V to 80V	±2.5mV	±2%

For consumer applications, we also offer the RT6050 、 RT6052 、 RT6053 and RT6056 .