HT7333A 3.3V 100mA LDO Voltage Regulator SOT-89

HT7333A 3.3V 100mA LDO Voltage Regulator SOT-89 is a high-accuracy, low-dropout (LDO) voltage regulator designed specifically to deliver a stable 3.3 V output from a wide range of input voltages. Utilizing CMOS technology, the HT7333A achieves ultra-low quiescent current, which makes it an exceptional choice for battery-powered and portable applications where power efficiency is paramount. Consequently, this regulator minimizes power loss while providing robust protection features to safeguard connected components. The small SOT-89 package allows engineers to integrate this essential power management component into space-constrained PCBs, guaranteeing a reliable and precise power source for sensitive digital circuits and microcontrollers. Therefore, developers often select the HT7333A when high performance, minimal heat generation, and prolonged battery life are critical design goals.

Key Features:

• Fixed 3.3V Output: The regulator delivers a highly accurate, pre-set output voltage of 3.3 V (±2%), perfect for powering common logic ICs and microcontrollers.
• Ultra-Low Quiescent Current (I_Q): Consumes very little current (typically 4 μA) when unloaded, significantly extending the operational life of battery-powered devices.
• Low Dropout Voltage: Requires only a small differential voltage (≈ 100 mV at 30 mA) between the input and output to maintain regulation, maximizing efficiency.
• Output Current Capability: Capable of sourcing a stable output current up to 100 mA, suitable for powering low-power wireless modules and sensors.
• Built-in Protection: Includes necessary current limiting and thermal shutdown features to protect the device and the load from excessive temperatures and short-circuit conditions.

Technical Specifications:

• Output Voltage (V_OUT): 3.3 V fixed
• Maximum Output Current (I_OUT): 100 mA
• Input Voltage Range (V_IN): 4.0 V to 12.0 V
• Dropout Voltage (V_DROP): Typically 180 mV at 100 mA
• Quiescent Current (I_Q): Typically 4 μA
• Output Voltage Accuracy: ±2%
• Operating Temperature Range: −40°C to +85°C

Mechanical Specifications:

• Package Type: SOT-89 (Surface Mount Technology)
• Mounting: Surface Mount Device (SMD)
• Thermal Resistance: Low thermal resistance due to the integrated metal tab, aiding heat dissipation.
• Lead Count: 3 pins (V_IN, GND, V_OUT)

Dimensions:

• Body Length: ≈ 4.4 mm
• Body Width: ≈ 4.0 mm
• Body Height: ≈ 1.5 mm
• Lead Pitch: Standard SOT-89 pitch
• Footprint: Small footprint, optimizing board space on compact designs.

Pinout and Wiring:

• Pin 1 (GND): Connect this pin to the circuit ground (0 V). The metal tab (center pin) is also connected to GND for thermal conductivity.
• Pin 2 (V_OUT): The regulated 3.3 V output pin. Always place a low-ESR output capacitor (typically 1 μF to 10 μF) close to this pin.
• Pin 3 (V_IN): Connect the unregulated input voltage (4.0 V to 12.0 V) to this pin. Use a bypass capacitor (typically 1 μF) near this pin for stability.
• Wiring Note: Ensure the thermal pad is soldered properly to a large copper area on the PCB to maximize heat sinking and maintain optimal performance at higher current loads.

Datasheet Reference:

• Download Holtek HT7333A LDO Regulator Datasheet

Commonly Used in:

• Wearable Electronics: The low quiescent current makes it ideal for smart watches, fitness trackers, and hearing aids.
• Battery-Powered Devices: Used as the primary 3.3V power source in toys, remote sensors, and portable meters.
• IoT Devices: Provides stable power for Wi-Fi and Bluetooth modules (e.g., ESP8266, nRF52) that require a precise 3.3 V supply.

Applications:

• Post-Regulation Filtering: Cleans up noisy power lines after a switching regulator (SMPS) to provide clean 3.3V power to sensitive analog circuits.
• Microcontroller Power: Serves as the dedicated power supply for 3.3V microcontrollers in low-power modes.
• Voltage Conversion: Converts higher battery voltages (e.g., 9V or 6V) down to the required 3.3V level efficiently.

Equivalent Models:

• AMS1117-3.3 (1A): While offering a higher current capability, the AMS1117 has a significantly higher quiescent current, however, it functions as a 3.3V replacement in non-battery applications.
• XC6206P332MR (Torex): A functionally similar 3.3V 100mA LDO in a different package, offering comparable low-power performance.
• LP2985AIM5-3.3 (TI): Another high-performance, low-power 3.3V LDO, furthermore, it provides excellent noise rejection.

Package Includes:

• 1 x HT7333A 3.3V 100mA LDO Voltage Regulator SOT-89