Diodes Incorporated ZXCT1109SA-7

Overview

ZXCT1109SA-7 from Diodes Incorporated is a high-side unipolar current sense monitor in SOT23-3 package, delivering 4 mA/V transconductance with ±1.8% gain accuracy, 3 µA quiescent current, and operation across 2.5 V to 36 V common-mode input range. It enables non-intrusive load current measurement in automotive power rails and industrial 24 V systems without ground-plane disruption.

For engineers reviewing the ZXCT1109SA-7 datasheet, ZXCT1109SA-7 pinout, ZXCT1109SA-7 application, or ZXCT1109SA-7 equivalent, key selection criteria include its single-supply line-powered architecture, S+ pin serving as both analog supply and high-side input, output current compliance up to 2.065 mA at 500 mV sense voltage, and AEC-Q100 Grade 1 qualification for automotive use.

Technical Context

The ZXCT1109SA-7 implements a precision current-output transconductance amplifier with internal biasing referenced to the S+ rail - eliminating need for external V_CC. Its differential input stage accepts V_SENSE = V_S+ − V_S− from 0 to 500 mV while rejecting common-mode voltages up to 36 V.

Output current I_OUT scales linearly with V_SENSE (I_OUT = 4 mA/V × V_SENSE), with temperature coefficient of 265 ppm/°C for transconductance and 370 ppm/°C for full-scale output current. The device operates over −40 °C to +125 °C with no external decoupling required.

Key Specifications

Pinout & Package

SOT23-3 package with exposed pad (no thermal pad designation in datasheet); compact 2.9 mm × 1.6 mm footprint suitable for space-constrained PCB layouts.

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 ZXCT1109SA-7 offers lowest power consumption and simplest analog interface for cost-sensitive, high-bandwidth high-side sensing - ideal where minimal component count and sub-µA standby current are critical.

Availability

ZXCT1109SA-7 is available at Aetrix Electronics and suitable for automotive battery management, industrial 24 V power rail monitoring, and USB-C PD adapter designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for ZXCT1109SA-7 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for automotive, industrial, and computing markets.

The ZXCT series targets high-side current sensing in space- and power-constrained applications, emphasizing ultra-low IQ, wide common-mode operation, and AEC-Q100 qualification for mission-critical systems.

FAQ

What is the minimum supply voltage required for ZXCT1109SA-7 operation?

The minimum S+ rail voltage is 2.5 V plus the output voltage (V_OUT) developed across R_GAIN. For example, with R_GAIN = 5 kΩ and I_OUT = 400 µA (at 100 mV sense), V_OUT ≈ 2 V → minimum S+ = 4.5 V. This constraint arises because pin 1 (OUT) serves as both output and substrate connection.

Can ZXCT1109SA-7 measure bidirectional current?

No - it is a unipolar high-side monitor designed only for positive current flow from S+ to S−. The device does not support reverse current detection or negative V_SENSE; attempting to drive V_S− > V_S+ violates absolute maximum ratings and may cause permanent damage.

How does the ZXCT1109SA-7 handle ESD and EMC in automotive environments?

It features 1000 V HBM and 150 V MM ESD ratings, and its high CMRR (>60 dB at 100 Hz) combined with recommended R_PROT/C₁ filtering (10–47 pF ceramic cap near S+/S− pins) suppresses RF rectification effects - validated per AEC-Q100 stress testing for automotive under-hood deployment.

Is an external gain-setting resistor mandatory for ZXCT1109SA-7 operation?

Yes - R_GAIN is required to convert the output current into a measurable voltage. Without it, the current output has no defined voltage reference and cannot interface with downstream circuitry. Typical values range from 1 kΩ (for 1 V full-scale at 1 mV/mA) to 100 kΩ (for high-impedance sampling), selected based on desired output swing and noise immunity.