3.3V, 600mA Step-Down Voltage Regulator D24V7F3

Overview

The D24V7Fx family of synchronous buck (step-down) voltage regulators generate lower voltages from input voltages as high as 36 V while supporting maximum continuous output currents of 600 mA across all combinations of input and output voltages. They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters), which makes them much more efficient than linear voltage regulators, especially when the difference between the input and output voltage is large. This family includes six versions with fixed output voltages ranging from 3.3 V to 12 V:

Regulator	Output voltage	Max continuous output current	Input voltage range1	Size	Special features	Price
#5592: D24V7F3	3.3 V	600 mA	4 V – 36 V	0.34″ × 0.54″	Short-circuit protection, thermal shutdown	$2.75
#5593: D24V7F5	5 V		5.1 V – 36 V
#5594: D24V7F6	6 V		6.1 V – 36 V
#5595: D24V7F7	7.5 V		7.6 V – 36 V
#5596: D24V7F9	9 V		9.2 V – 36 V
#5597: D24V7F12	12 V		12.2 V – 36 V
Note 1: Minimum input voltage is subject to dropout voltage considerations; see the dropout voltage section of product pages for more information.

The regulators feature short circuit protection and thermal shutdown protection, which helps prevent damage from overheating. The boards do not have built-in protection against reverse voltage, but reverse-voltage protection modules are available for adding that functionality.

We manufacture these boards in-house at our Las Vegas facility, so we can make these regulators with customized components to better meet the needs of your project, such as by customizing the output voltage. If you are interested in customization, please contact us for a quote.

Details for item #5592

This item is the D24V7F3, which outputs a fixed 3.3 V.

3.3V, 600mA Step-Down Voltage Regulator D24V7F3.

3.3V, 600mA Step-Down Voltage Regulator D24V7F3.

Step-Down Voltage Regulator D24V7Fx, bottom view.

Features

• Input voltage: 4 V to 36 V
• Output voltage: 3.3 V with 4% accuracy
• Maximum output current: 600 mA continuous for all combinations of input and output voltage
• Fixed 1.1 MHz switching frequency for normal loads (frequency is reduced at light loads to increase efficiency)
• Very low quiescent current: < 0.01 mA for most of the operating range (see the quiescent current graph below)
• Short-circuit and over-temperature protection
• Small size: 0.34″ × 0.54″ × 0.16″ (8.6 mm × 13.7 mm × 4.1 mm)
• Weight: 0.5 g

Connections

This regulator has three connections: input voltage (VIN), ground (GND), and output voltage (VOUT).

The input voltage, VIN, powers the regulator. Voltages between 4 V and 36 V can be applied to VIN, but generally the effective lower limit of VIN is VOUT plus the regulator’s dropout voltage, which varies approximately linearly with the load (see below for graphs of the dropout voltage as a function of the load). Additionally, please be wary of destructive LC spikes (see below for more information).

VOUT is the regulated output voltage.

The three connections are labeled on the back side of the PCB and are arranged with a 0.1″ spacing along the edge of the board for compatibility with solderless breadboards, connectors, and other prototyping arrangements that use a 0.1″ grid. You can solder wires or 0.1″ header pins directly to the board. Note: header pins are not included with this product, but 1×3 straight male headers and 1×3 right-angle male headers are available separately.

D24V7Fx step-down voltage regulators, soldered with straight and right-angle headers (not included), on a breadboard.

Typical efficiency

The efficiency of a voltage regulator, defined as (Power out)/(Power in), is an important measure of its performance, especially when battery life or heat are concerns.

Quiescent current

The quiescent current is the current the regulator uses just to power itself, and the graph below shows this for the different regulator versions as a function of the input voltage.

Typical dropout voltage

The dropout voltage of a step-down regulator is the minimum amount by which the input voltage must exceed the regulator’s target output voltage in order to ensure the target output can be achieved. For example, if a 5 V regulator has a 1 V dropout voltage, the input must be at least 6 V to ensure the output is the full 5 V. Generally speaking, the dropout voltage increases as the output current increases. (Note that for the 3.3 V version, the dropout is at least 700 mV due to the regulator’s 4 V minimum operating voltage.) The graph below shows the dropout voltages for the different members of this regulator family as a function of output current.

LC voltage spikes

When connecting voltage to electronic circuits, the initial rush of current can cause voltage spikes that are much higher than the input voltage. If these spikes exceed the regulator’s maximum voltage (36 V), the regulator can be destroyed. In our tests with typical power leads (~30″ test clips), we observed spikes approaching 36 V at input voltages approaching 20 V. Power supplies or leads with high inductance will make these spikes worse. An electrolytic capacitor (33 μF is a good starting point) can be added close to the regulator between VIN and GND to help suppress these spikes.

More information about LC spikes can be found in our application note, Understanding Destructive LC Voltage Spikes.