Tag: Voltage Regulation

78Lxx Series Voltage Regulators: Pinout, Datasheet, and Features Guide {TL00007}

The 78Lxx series is a family of fixed-output linear voltage regulators designed for low-current applications. Often called “universal” regulators, they are found in almost every type of electronic device, from industrial equipment to household appliances. Their primary job is to take a fluctuating or high input voltage and provide a rock-steady, clean output.

This guide explores the full range of the 78Lxx family, covering everything from the popular 5V version to the high-voltage 24V models.

Key Features of the 78Lxx Family

  • Wide Voltage Range: Available in multiple fixed output voltages to suit any circuit.

  • High Input Tolerance: Capable of handling input voltages up to 30V–35V, much higher than LDO regulators.

  • Ease of Use: Requires only two external capacitors to function perfectly.

  • Robust Protection: Includes built-in thermal shutdown and internal current limiting to prevent the chip from burning out during a fault.

The 78Lxx Voltage Lineup

The “xx” in the part number represents the output voltage. While they all look the same physically, their internal tuning is different.

1. Common Low-Voltage Models

  • 78L05 (5V)/78L06 (6V): The industry standard for digital logic, microcontrollers, and sensors.

  • 78L08 (8V): Frequently used in audio equipment and older analog signaling.

  • 78L09 (9V)/78L10 (10V): The perfect choice for replacing 9V batteries in portable gadgets.

2. High-Voltage Models

  • 78L12 (12V): Used for powering relays, small DC fans, and LED strings.

  • 78L15 (15V): Common in industrial automation and operational amplifier (Op-Amp) power rails.

  • 78L24 (24V): Used in specialized high-voltage communication interfaces.

Available Packages

Depending on your PCB design, the 78Lxx is available in several form factors:

  1. TO-92 (Through-Hole): The most common “transistor-style” package used by hobbyists and for breadboarding.

  2. SOIC-8 (Surface Mount): A standard 8-pin SMD package used for automated high-volume production.

  3. SOT-89 (Surface Mount): A flat SMD package with a thermal pad for better heat management in compact designs.

                                                                                                       78Lxx TO-92 CAD Model 

    78L05 Datasheet - 5V Positive Voltage Regulator                                   Package: TO92 (Type B)      

                78Lxx  SOIC-8 CAD Model                               78Lxx SOT-89  CAD Model

        SOIC8-N | Toshiba Electronic Devices & Storage Corporation | Asia-English             PG-SOT89-4-2 | Infineon Technologies

Technical Specification Overview

Parameter Value (Standard)
Input Voltage (Max) 30V (for 5V–9V models) / 35V (for 12V–24V)
Output Current 100mA (Max)
Dropout Voltage ~1.7V to 2.0V
Quiescent Current 3mA – 6mA
Operating Temp 0°C to 125°C

Pro-Tips for Universal Integration

  • The “2-Volt” Rule: Always ensure your input voltage is at least 2V higher than your target output. For a 78L05, you need at least 7V input.

  • Polarity Check: Remember that the 78Lxx is for Positive voltages. If you are designing a dual-rail power supply and need a negative version, use the 79Lxx series (e.g., 79L05 for -5V).

  • Thermal Management: Even though they are “universal,” they are not for high power. If you try to drop 24V down to 5V at 100mA, the chip will get very hot (P = (Vin – Vout) \ I).

  • Capacitor Choice: Use ceramic capacitors (0.33μF on input, 0.1μF on output) to ensure the regulator doesn’t “whistle” (oscillate) at high frequencies.

Alternatives for 78Lxx

LM317L (Adjustable version), AMS1117 (LDO version), LP2950 (Low Quiescent), MCP1700

Read More

AMS1117 Technical Reference: 1.2V to 5V Voltage Regulator {TL00001}

The AMS1117 series is one of the most popular low dropout (LDO) voltage regulators used in modern electronics. Known for its reliability and ease of use, it provides a stable power supply for everything from simple LED circuits to complex microcontrollers like the ESP32 or Arduino.

This guide explores the different varieties of the AMS1117, including fixed and adjustable versions across various packages.

Key Features of the AMS1117

  • High Efficiency Output: Delivers up to 1A of output current.

  • Low Dropout Performance: Operates with a typical dropout of only 1.1V to 1.3V at full load.

  • Thermal Protection: Features on-chip thermal limiting to shut down the regulator if it exceeds 165°C.

  • Short Circuit Safety: Built-in current limiting minimizes stress on your circuitry during overload conditions.

Voltage Varieties and Packages

The AMS1117 is available in two main formats: Fixed and Adjustable.

1. Fixed Voltage Models

These are pre-set to specific voltages, requiring no external resistors for operation:

  • AMS1117-1.2V: Perfect for low-voltage core logic.

  • AMS1117-1.5V: Used in specialized digital signaling.

  • AMS1117-1.8V: Standard for many FPGA and ARM processor cores.

  • AMS1117-2.5V: Common for networking and communication ICs.

  • AMS1117-3.3V: The most popular choice for powering 3.3V microcontrollers and WiFi modules.

  • AMS1117-5.0V: Standard for TTL logic and 5V digital systems.

2. The Adjustable Version (AMS1117-ADJ)

The ADJ version allows you to set a custom output voltage using two external resistors (R1 and R2). It develops a 1.25V reference voltage (Vref) between the output and adjust terminal.

The Full Adjustment Formula:

  • Vref: Reference Voltage (typically 1.25V).

  • R1: Resistor between OUT and ADJ pins (usually 120Ω).

  • R2: Resistor between ADJ pin and Ground.

  • Iadj: Adjustment pin current (typically a negligible 50uA).

  • ams1117 ciruit.jpgAMS1117 circuit2.jpg

3. Available Packages

Depending on your space and heat requirements, you can find the AMS1117 in several form factors:

  • SOT-223: The most common 3-lead surface mount package for hobbyist modules.

  • SOT-89: A smaller, low-profile version for compact mobile devices.

  • TO-252 (DPAK): A larger package that offers better heat dissipation for high-power applications.                                                                                                     

                                                                                                                    AMS1117 SOT-223 CAD Model 

    AMS1117 1A Low Dropout Voltage Regulator: Datasheet, 3.3 V Regulators and Pinout

                           AMS1117 TO-89 CAD Model                                        AMS1117 SOT-89 CAD Model

    PG-TO252-3-342 | Infineon TechnologiesPG-SOT89-4-2 | Infineon Technologies

Technical Specification Overview

Parameter Value
Max Input Voltage 15V (Absolute Maximum)
Output Current 1A
Reference Voltage (ADJ) 1.25V
Line Regulation 0.2% Max
Operating Temperature -40°C to 125°C

Pro-Tips for Stability

  1. Output Capacitors: The AMS1117 requires an output capacitor for stability. A 22μF solid tantalum capacitor is highly recommended to ensure it doesn’t oscillate under load.

  2. Heat Management: The tab of the SOT-223 package is electrically connected to the Output pin. Use a large copper area on your PCB to act as a heat sink, as the regulator dissipates heat through the board.

  3. Protection Diodes: Generally, protection diodes are not needed unless you are using very large output capacitors (above 1000μF) that could discharge back into the regulator.

 

Alternatives for AMS1117

LM1117, LM317, LM7805, NTE9060

 

Read More

Type to search

Shopping cart

0
image/svg+xml

No products in the cart.

Continue Shopping