Overview

The D45V1Ex line of synchronous buck (step-down) voltage regulators generate lower voltages from input voltages as high as 65 V while delivering up to 100 mA continuous. They are switching regulators with very low quiescent currents (< 30 μA typical), which allows for extra high efficiencies at low currents compared to linear regulators and typical switching regulators. This kind of regulator is also called a switched-mode power supply (SMPS) or DC-to-DC converter.

D45V1ExFx line of step-down voltage regulators: D45V1E2Fx (left) and D45V1E1Fx (right).

This line consists of the D45V1E1Fx family, which is just 0.3″ × 0.5″ and intended for applications with tighter space constraints, and the larger (0.5″ × 0.6″) D45V1E2Fx family, which features a precision-threshold enable input for turning the regulator off and a power-good output that can be used for sequencing and voltage monitoring.

	Regulator	Output voltage	Input voltage1	Max output current	Size	EN input + PG output	Price
D45V1E1Fx	#5362: D45V1E1F3	3.3 V	3.3 V – 65 V	100 mA	0.3″ × 0.5″	–	$4.69
	#5363: D45V1E1F5	5 V	5 V – 65 V
	#5367: D45V1E1F12	12 V	12 V – 65 V
D45V1E2Fx	#5372: D45V1E2F3	3.3 V	3.3 V – 65 V	100 mA	0.5″ × 0.6″		$4.69
	#5373: D45V1E2F5	5 V	5 V – 65 V
	#5377: D45V1E2F12	12 V	12 V – 65 V
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 reverse-voltage protection.

We manufacture these boards in-house at our Las Vegas facility, which gives us the flexibility to 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 #5373

This item is the D45V1E2F5, which measures 0.5″×0.6″ and outputs a fixed 5 V.

5V, 100mA Step-Down Voltage Regulator D45V1E2F5.

D45V1E2Fx Step-Down Voltage Regulator bottom view.

Features

• Input voltage: 5 V to 65 V (minimum input subject to dropout voltage considerations; see the dropout voltage section for details)
• Output voltage: 5 V with 4% accuracy
• Maximum output current: 100 mA
• Low quiescent current: < 20 μA (see the quiescent current graph below)
• High efficiencies at light loads (see the efficiency graph below)
• Enable input with precision threshold can be used for simple on/off control or to implement a custom low-voltage cutoff
• Power-good output can be used for sequencing, fault detection, and voltage monitoring
• Short-circuit and over-temperature protection
• Small size: 0.5″ × 0.6″ × 0.11″ (12.7 mm × 15.3 mm × 3 mm)
• Weight: 0.7 g

Connections

D45V1E2Fx step-down voltage regulator pinout.

This regulator has five connections: power good (PGOOD), enable (EN), input voltage (VIN), ground (GND), and output voltage (VOUT).

The “power good” indicator, PGOOD, is an open-drain output that goes low when the regulator’s output voltage falls below 87% of the target voltage and becomes high impedance when the output voltage rises above 94% of the target voltage. An external pull-up resistor is required to use this pin. The recommended pull-up value is 10 kΩ to 100 kΩ, and it should not be pulled up to a rail exceeding 12 V.

The regulator, which is enabled by default, can be put into a low-power sleep state by reducing the voltage on the EN pin below 1.1 V (typical; the actual falling threshold can vary between 1.11 V and 1.18 V from unit to unit), and it can be brought out of this state again by increasing the voltage on EN past 1.2 V (typical; the actual rising threshold can vary between 1.16 V and 1.26 V). The shutdown current draw in this sleep mode is approximately 5 μA plus 1 μA per volt on VIN. (Note that for high input voltages, the shutdown current draw when it is disabled can be greater than the quiescent draw while enabled; see the quiescent current graph below for more details.)

A low-voltage cutoff can be set by adding an appropriately sized external pull-down resistor between EN and GND. This resistor and the on-board 1 MΩ pull-up would together form a VIN voltage divider with the output connected to EN.

The input voltage, VIN, powers the regulator. Voltages between 5 V and 65 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).

VOUT is the regulated output voltage.

The five 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 straight male header strips and right-angle male header strip are available separately.

D45V1ExFx step-down voltage regulators, soldered with straight header pins(not included), on a breadboard.

D45V1ExFx step-down voltage regulators, soldered with right-angle header pins (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.

Maximum continuous output current

The maximum achievable output current of these regulators varies with the input voltage but also depends on other factors, including the ambient temperature, air flow, and heat sinking. The graph below shows maximum output currents that these regulators can deliver continuously at room temperature in still air and without additional heat sinking.

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. On the D45V1E2 versions, the EN input can be driven low to put it in a low-power sleep state where the current draw is approximately 5 μA plus 1 μA per volt on VIN.

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. The graph below shows the dropout voltages for the different members of this regulator family:

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 (65 V), the regulator can be destroyed. In our tests with typical power leads (36″/1m test clips), we observed spikes approaching 65 V at input voltages around 30 V.

If you are connecting more than 30 V or your power leads or supply has high inductance, we recommend soldering a suitably rated 33 μF or larger electrolytic capacitor close to the regulator between VIN and GND.

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