Diodes Incorporated AP7353D-33CV4-7

Overview

AP7353D-33CV4-7 from Diodes Incorporated is a 250mA low-dropout linear regulator with fixed 3.3V output, ±1% accuracy, 90dB PSRR at 1kHz, 10µV_rms output noise (10Hz–100kHz), and 18µA typical quiescent current. It features enable control, thermal shutdown, short-circuit protection, and built-in output discharge - optimized for RF power supplies and battery-powered portable electronics.

For engineers reviewing the AP7353D-33CV4-7 datasheet, AP7353D-33CV4-7 pinout, AP7353D-33CV4-7 application, or AP7353D-33CV4-7 equivalent, key selection criteria include dropout voltage at 250mA (65mV typ. @ 3.3V), EN logic thresholds (0.4V low / 1.2V high), thermal resistance (150°C/W), and compatibility with 1µF ceramic output capacitors in space-constrained layouts.

Technical Context

The AP7353D integrates a CMOS-based error amplifier, precision voltage reference, current-limit circuit, and thermal shutdown protection. Its internal discharge FET actively pulls the output to ground when disabled - eliminating residual voltage on downstream circuits during power-down sequences.

This regulator operates across 2.0V–5.5V input range and maintains stable 3.3V output under load transients up to 250mA. Fast load transient response (<20µs settling) and high PSRR (>70dB at 10kHz) make it suitable for noise-sensitive analog/RF rails where supply ripple rejection and clean turn-off behavior are critical.

Key Specifications

Pinout & Package

X1-WLB0707-4 (Type A1) is a 0.64mm × 0.64mm wafer-level chip-scale package (WLCSP) with 4 solder bumps and an exposed thermal pad. Its ultra-small footprint supports high-density portable PCB layouts while enabling efficient heat dissipation via direct thermal connection to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with AP7353D-33CV4-7, AP7361D-33YG-7 trades footprint for current headroom and thermal performance, while MCP1703T-3302E/MB prioritizes noise reduction at the expense of discharge capability and quiescent efficiency - making AP7353D optimal for space-constrained, battery-sensitive, and sequenced-power applications.

Availability

AP7353D-33CV4-7 is available at Aetrix Electronics and suitable for smartphone RF supplies, wearable sensor hubs, portable camera modules, and industrial handheld scanners requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for AP7353D-33CV4-7 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-performance power management, signal integrity, and protection solutions for consumer, industrial, and automotive markets.

The AP7353 series belongs to Diodes' high-PSRR, low-noise LDO portfolio designed specifically for noise-sensitive portable electronics - emphasizing small footprint, fast transient response, and intelligent power control features like integrated discharge.

FAQ

What is the purpose of the exposed pad (EP) on AP7353D-33CV4-7?

The exposed pad is a thermal and electrical connection to the die substrate. It must be soldered to a large PCB copper area tied to GND to dissipate heat effectively. While electrically connected to GND internally, it is not intended as a primary current-carrying ground path - its main role is thermal relief, lowering junction temperature by up to 30°C under full load.

Does AP7353D-33CV4-7 require an external pull-up resistor on the EN pin?

No external pull-up is required. The EN pin has no internal pull-up; however, it must never be left floating. For always-on operation, connect EN directly to IN. For controlled enable/disable, drive it with a GPIO capable of meeting V_EN(HI) ≥1.2V and V_EN(LO) ≤0.4V - no additional biasing components are needed.

How does the built-in discharge function operate, and when is it active?

The discharge FET activates only when EN is driven low (≤0.4V), connecting OUT to GND through a 35Ω channel. It remains inactive during normal regulation (EN high) and does not affect output impedance or load regulation. This feature ensures rapid, controlled discharge of output capacitance after shutdown - critical for preventing latch-up in downstream logic.

Can AP7353D-33CV4-7 be used with input voltages below 2.0V?

No. The absolute minimum input voltage is 2.0V per datasheet specifications. Operation below this threshold risks improper regulation, increased dropout, or failure to start. At 3.3V output, the minimum functional input is 3.365V (65mV dropout + 3.3V); for lower VIN applications, consider a different LDO with sub-2V operation capability.