Diodes Incorporated ZXCT1020E5TA

Overview

ZXCT1020E5TA from Zetex Semiconductors is a precision high-side current sense monitor with current-output architecture, designed to measure load current without disrupting the ground plane. It operates from 2.5V to 20V supply, delivers 1% typical accuracy at 100mV sense voltage, and features 25µA quiescent current in SOT23-5 package-enabling accurate battery charger and motherboard power rail monitoring.

For engineers reviewing the ZXCT1020E5TA datasheet, ZXCT1020E5TA pinout, ZXCT1020E5TA application, or ZXCT1020E5TA equivalent, key selection considerations include programmable gain via external RG/RSH ratio, low 3mV typical offset enabling 3% accuracy at 10mV VSENSE, output impedance set by RG, PSRR of 70–80dB, and SOT23-5 footprint compatibility with ZXCT1021/1022.

Technical Context

The ZXCT1020 functions as a transconductance amplifier: S+ and S− sense differential voltage across a shunt resistor (VSENSE), while VB supplies bias referenced to the monitored rail. Its current-output architecture decouples gain setting from internal circuitry-gain = RG / RSH-and allows output impedance to match RG value for optimal load driving.

It supports wide common-mode input (2.5V–20V) and differential sense range (0–1.5V), with temperature coefficient of 50–300 ppm/°C on output voltage and bandwidth scaling from 300 kHz (10mV input) to 2 MHz (100mV input). PSRR remains stable across full VB range, critical for noisy power rail sensing.

Key Specifications

Pinout & Package

SOT23-5 package (JEDEC MO-178AA), 1.45mm max height, 2.7–3.1mm length, 2.2–3.2mm width, 0.95mm lead pitch. RoHS-compliant, halogen-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current monitor applications.

Compared with MAX4080TASA+ and INA219AIDR, the ZXCT1020E5TA uniquely balances programmable analog gain, ultra-low quiescent current, and SOT23-5 footprint-making it optimal for cost-sensitive, space-constrained, and battery-operated designs requiring analog feedback without microcontroller dependency.

Availability

ZXCT1020E5TA is available at Aetrix Electronics and suitable for battery chargers, server power supply telemetry, over-current protection circuits, and programmable current source feedback requiring stable component supply and long-term production continuity.

Supply support for ZXCT1020E5TA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Zetex Semiconductors (now part of Diodes Incorporated) is a UK-based designer of high-performance analog and discrete semiconductors, ISO 9001 and TS16949 certified, with focus on precision sensing, power management, and signal conditioning.

The ZXCT series was developed specifically for high-accuracy, high-side current monitoring in space-constrained and low-power applications-including portable electronics, computing power delivery, and industrial control systems-prioritizing offset performance, supply flexibility, and PCB footprint efficiency.

FAQ

What is the maximum allowable voltage difference between VB and S+?

The datasheet specifies that S+ must never go more than 6V below VB (absolute maximum rating note a). This constraint protects the internal ESD structures and ensures proper biasing of the sense amplifier. Exceeding this differential risks permanent damage-even if VB itself remains within 20V limit-so external clamping diodes are recommended for systems with large transients or hot-swap events.

Can ZXCT1020E5TA measure bidirectional current?

No. The ZXCT1020E5TA is unidirectional: its S+ and S− inputs are internally biased to operate only when S+ is at higher potential than S−, corresponding to forward current flow through the shunt. Attempting reverse current results in output saturation near 0V and loss of linearity. For bidirectional sensing, a dedicated dual-supply or rail-to-rail device such as the INA226 is required.

How does output impedance relate to RG, and why does it matter?

The OUT pin presents an output impedance equal to RG (the resistor connected from OUT to GND). This is intentional: it ensures the output voltage VOUT = IOUT × RG remains linear and predictable. Matching RG to the input impedance of the downstream stage (e.g., ADC or op-amp) avoids loading errors-especially critical when driving capacitive traces or high-impedance nodes where instability or bandwidth reduction may occur.

Is ZXCT1020E5TA suitable for automotive applications?

The ZXCT1020E5TA is rated for −40°C to +85°C ambient operation and meets AEC-Q200 stress test recommendations for passive components, but it is not officially AEC-Q100 qualified as an integrated circuit. Its 125°C junction rating and robust PSRR make it functionally viable in under-hood auxiliary modules (e.g., body control unit current telemetry), provided system-level qualification and derating per ISO/TS 16949 are performed by the end customer.