Diodes Incorporated AP7375-33W5-7

Overview

AP7375-33W5-7 from Diodes Incorporated is a 3.3V fixed-output, wide-input (3–45V), 300mA ultra-low-dropout linear regulator in SOT25 package with 2.1μA quiescent current, EN pin rated to 45V, and ±2% output accuracy-designed for battery-powered smoke detectors requiring stable low-power voltage regulation under wide input transients.

For engineers reviewing the AP7375-33W5-7 datasheet, AP7375-33W5-7 pinout, AP7375-33W5-7 application, or AP7375-33W5-7 equivalent, this page delivers verified electrical parameters, thermal performance data, SOT25 pin mapping, real-world transient response behavior, and validated alternative LDOs for high-voltage industrial sensor nodes.

Technical Context

The AP7375-33W5-7 integrates a high-voltage PMOS pass transistor enabling operation up to 45V input while maintaining 35mV dropout at 10mA and 350mV at 100mA. Its EN pin accepts up to 45V directly-eliminating external level-shifting circuitry in automotive or industrial supply rails.

It delivers 85dB PSRR at 1kHz and achieves no overshoot during startup or short-circuit recovery via internal compensation. Thermal shutdown triggers at +150°C with +20°C hysteresis, and short-circuit current limit is internally set to ~500mA.

Key Specifications

Pinout & Package

SOT25 (Package Code W5) is a 5-pin surface-mount package with exposed thermal pad (EP), optimized for thermal dissipation in space-constrained applications. Pin 4 is NC (recommended tied to GND); Pin 5 is EP (exposed pad), intended for large copper area connection to GND for thermal management-not as primary GND electrode.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-IQ, wide-input LDO applications.

Compared with AP7375-33W5-7, AP7361-33W5-7 trades 9V input headroom for cost savings in sub-36V systems, while MCP1703T-3302E/MB sacrifices enable control, output current, and thermal efficiency for legacy SOT89 compatibility.

Availability

AP7375-33W5-7 is available at Aetrix Electronics and suitable for battery-powered equipment, smoke detectors and sensors, microcontroller applications, and home appliances requiring stable component supply with long-lifecycle support.

Supply support for AP7375-33W5-7 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 semiconductor company specializing in discrete, analog, and mixed-signal solutions for industrial, computing, consumer, and communications markets.

The AP7375 series belongs to Diodes' high-voltage LDO product line, engineered specifically for robust, low-power regulation in battery-backed safety systems and harsh industrial environments where wide input range and ultra-low IQ are critical.

FAQ

What is the minimum input voltage required for regulation at 3.3V output?

The AP7375-33W5-7 requires VIN ≥ (VOUT + VDROP(MAX)). With VDROP(MAX) = 360mV at 100mA per datasheet, minimum VIN is 3.66V under full load. At light load (10mA), VDROP drops to 50mV, allowing regulation down to 3.35V. The device will not regulate below 3.0V VIN regardless of load.

Can the EN pin be left floating?

No. The EN pin has no internal pull-up or pull-down; floating EN causes undefined output state and potential oscillation. It must be actively driven high (≥1V) to enable or low (≤0.4V) to disable. For default-on operation, tie EN directly to VIN through a 100kΩ resistor-valid since EN tolerates up to 45V.

Is the exposed pad (Pin 5) electrically connected internally?

No. The exposed pad (EP) is thermally connected to the die but not electrically tied to any internal node. Per datasheet, it should be connected to a large GND copper area for thermal dissipation-but not used as the sole GND return path. Electrical GND must still be routed through Pin 2.

Does AP7375-33W5-7 require an input capacitor?

Yes. A minimum 1μF X7R/X5R ceramic capacitor is required between VIN and GND, placed within 2mm of the pins. This stabilizes the input impedance, suppresses high-frequency noise, and prevents oscillation during fast load transients. Larger values improve immunity but are not mandatory.