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Full machine-readable index: https://core-electronics.com.au/llms.txt # 24V, 4A Step-Down Voltage Regulator D42V55F24 **Type:** Product page · **SKU:** POLOLU-5579 · **Brand:** [Pololu](https://core-electronics.com.au/brands/pololu-australia) **Page:** https://core-electronics.com.au/pololu-24v-4a-step-down-voltage-regulator-dc-dc-buck-converter-d42v55f24.html ([markdown](https://core-electronics.com.au/pololu-24v-4a-step-down-voltage-regulator-dc-dc-buck-converter-d42v55f24.html.md)) Note 1: Typical continuous output current at 42 V in. Actual achievable continuous output current is a function of input voltage and is limited by thermal... ## Pricing - **Price:** $52.40 (inc GST) — $47.64 AUD, exc GST - **Quantity discounts:** 6+ $45.73 (exc GST) · 12+ $44.30 (exc GST) ## Availability & dispatch - Available with a lead time — expect dispatch between Sep 02 and Sep 07. ## How to buy - **Build a cart:** compose `https://core-electronics.com.au/cart/link?items=POLOLU-5579:1` (comma-separated SKU:qty pairs) and share the link. Opening it shows a confirmation page with live pricing and stock before anything is added to the cart. - **Verify the cart first:** fetch `https://core-electronics.com.au/cart/link/POLOLU-5579:1.md` for live line prices (inc & exc GST, quantity discounts applied), stock and dispatch estimates, and totals. Append `/to/{AU-postcode}` (or `/to/{country-code}:{postcode}`) before `.md` for delivery options and prices to that destination. Unknown, retired, or out-of-stock SKUs are flagged. (Query form `cart/link.md?items=...` also works but some robots parsers refuse query strings here.) - **Checkout** is completed on-site and includes a captcha at the payment step. Share the cart link; checkout takes it from there. - **Search the catalogue:** `https://core-electronics.com.au/search/{query}.md` (URL-encode the query; pages 2-3 at `search/{query}/{page}.md`; `search.md?q=` also works) - **Payment methods, purchase orders, policies and contact details:** https://core-electronics.com.au/llms.txt ## Description | [![](https://core-electronics.com.au/attachments/localcontent/20746_f6a6cba035bf0e2a0fe5a528ed5719cb.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13517_13682c272bd.jpg) | |---| The D42V55Fx family of synchronous buck (step-down) voltage regulators generates lower output voltages from input voltages as high as 60 V. 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. These regulators can typically support continuous output currents between 3 A and 8 A, depending on the input voltage and output voltage (see the *Maximum continuous output current* section below). In general, the available output current is higher for the lower-voltage versions than it is for the higher-voltage versions, and it decreases as the input voltage increases. This family includes ten versions with fixed output voltages ranging from 3.3 V to 24 V: | Regulator | Output voltage | Typical max output current(1) | Input voltage range(2) | Size | |---|---|---|---|---| | [\#5570: D42V55F3](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5570) | 3.3 V | 6 A | 3.5 V – 60 V | 1" × 1" | | [\#5571: D42V55F5](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5571) | 5 V | 6 A | 5 V – 60 V | | [\#5572: D42V55F5.3](https://core-electronics.com.au/pololu-5-3v-6a-step-down-buck-dc-dc-voltage-regulator-d42v55f53.html) | 5.3 V | 6 A | 5.3 V – 60 V | | [\#5573: D42V55F6](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5573) | 6 V | 5.5 A | 6 V – 60 V | | [\#5574: D42V55F7](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5574) | 7.5 V | 5 A | 7.5 V – 60 V | | [\#5575: D42V55F8](https://core-electronics.com.au/pololu-8-4v-5a-step-down-voltage-regulator-buck-dc-dc-converter-d42v55f8.html) | 8.4 V | 5 A | 8.4 V – 60 V | | [\#5576: D42V55F9](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5576) | 9 V | 5 A | 9 V – 60 V | | [\#5577: D42V55F12](https://core-electronics.com.au/12v-45a-buck-step-down-voltage-regulator-dc-dc-converter-pololu-d42v55f12.html) | 12 V | 4.5 A | 12 V – 60 V | | [\#5578: D42V55F18](https://core-electronics.com.au/catalog/product/view/sku/POLOLU-5578) | 18 V | 4 A | 18 V – 60 V | | [\#5579: D42V55F24](https://core-electronics.com.au/pololu-24v-4a-step-down-voltage-regulator-dc-dc-buck-converter-d42v55f24.html) | 24 V | 4 A | 24 V – 60 V | | | | Note 1: Typical continuous output current at 36 V in. Actual achievable continuous output current is a function of input voltage and is limited by thermal dissipation. See the output current graphs on the product pages for more information. | | | | Note 2: Minimum input voltage is subject to dropout voltage considerations; see the dropout voltage section of product pages for more information. | The regulators have input reverse voltage protection and over-current protection. A thermal shutdown feature also helps prevent damage from overheating and a soft-start feature limits the inrush current and gradually ramps the output voltage on startup. Pololu manufacture these boards in-house at Pololu's Las Vegas facility, so Pololu 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](https://core-electronics.com.au/contact). If you do not need quite as much current, consider the very similar [D36V28Fx](https://core-electronics.com.au/power-batteries/regulators-and-converters/step-down.html) or [D30V30Fx](https://core-electronics.com.au/category/307/d30v30fx-step-down-voltage-regulators) families of step-down voltage regulators, which can deliver up to around 4 A in a wide range of output voltages. **Details for item #5579** | \| [![](https://core-electronics.com.au/attachments/localcontent/47673_bdc887deeaca77748999d21c7415fa9e.jpg)](https://core-electronics.com.au/attachments/localcontent/1157790_6ebf089569012c7eb62a14aec697411c.jpg) \| \|---\| \| 24V, 4A Step-Down Voltage Regulator D42V55F24, top view. \| | \| [![](https://core-electronics.com.au/attachments/localcontent/55125_94cbadd9c0e48b11a8edcefb4d7c564d.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13516_13283f268a9.jpg) \| \|---\|---\| \| 24V, 4A Step-Down Voltage Regulator D42V55F24, bottom view. \| | \| [![](https://core-electronics.com.au/attachments/localcontent/10670_9e8be924d09d37e82f1a833906c8b5d3.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13520_2190228ea46.jpg) \| \|---\|---\| | |---| **Features** - Input voltage: 24 V to 60 V (minimum input subject to dropout voltage considerations; see the [dropout voltage section](https://core-electronics.com.au/#dropout) for details) - Output voltage: 24 V with 3% accuracy - Typical maximum continuous output current: 2.5 A to 5 A (see the [maximum continuous output current graph](https://core-electronics.com.au/#maxcurrent) below) - Typical efficiency of 90% to 95%, depending on input voltage, output voltage, and load (see the [efficiency graph](https://core-electronics.com.au/#efficiency) below) - Switching frequency: ~400 kHz under heavy loads - < 0.2 mA typical no-load quiescent current (see the [quiescent current graph](https://core-electronics.com.au/#quiescent) below) - Optional enable input for disconnecting the load and putting the regulator into a low-power state that typically draws under 0.1 mA - Power-good output can be used for sequencing, fault detection, and voltage monitoring - Soft-start feature limits inrush current and gradually ramps output voltage - Integrated reverse-voltage protection, over-current protection, and over-temperature shutoff - Compact size: 1" × 1" × 0.43" (25.4 mm × 25.4 mm × 11 mm) - Three 0.086" mounting holes for #2 or M2 [screws](https://core-electronics.com.au/hardware/screws-nuts.html) **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. | [![](https://core-electronics.com.au/attachments/localcontent/71952_466bb5f655e0cbd988ffa53ea80e9f95.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13529_73070368481.png) | |---| **Connections** This regulator has six connections, some of which are duplicated on multiple pins: | [![](https://core-electronics.com.au/attachments/localcontent/0J13518_644976f3ed8.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13518_30463ab3c19.jpg) | |---| | Pin | Type | Function | |---|---|---| | VOUT | output | Regulated output voltage. | | GND | – | Ground. | | VIN | input | Input power for the regulator. Voltages between 3.5 V and 60 V can be applied to VIN, but generally the effective lower limit of VIN is VOUT plus the regulator’s dropout voltage, which varies with the load (see below for [graphs of the dropout voltage](https://core-electronics.com.au/#dropout) as a function of the load). | | VRP | output or input | Provides access to the input voltage after reverse-voltage protection. This pin can be used as an output to power other devices or as an input point for the supply voltage that bypasses the reverse protection on VIN. | | PG | open-drain output | Optional “Power Good” indicator that goes low when the regulator’s output voltage either rises more than 10% above or falls more than 8% below the nominal voltage (typical, with hysteresis). It drives low during soft start and while the regulator is disabled. An external pull-up resistor to the desired logic voltage rail is required to use this pin (100 kO recommended). | | EN | input | Optional enable input that is pulled up to VIN by default through a 1 MO resistor. Reduce the voltage on this pin below 0.5 V to disconnect the load and put the regulator into a low-power shutdown mode that draws approximately 50 µA plus 1 µA per volt on VIN. Shutdown mode can be exited by bringing the EN voltage above 1 V. This pin can be left disconnected if this feature is not required. | All of the connections are arranged on a 0.1" grid for compatibility with solderless [breadboards](https://core-electronics.com.au/prototyping/breadboards.html), [0.1" male headers](https://core-electronics.com.au/connectors-sockets/headers.html), and [0.1" female headers](https://core-electronics.com.au/connectors-sockets/headers/female-straight.html). The power connections (VOUT, GND, VIN, and VRP) are duplicated across both rows of through-holes, allowing two header pins to be used for each connection. Note that the EN and PG pins are not duplicated and are adjacent on different rows, so if you intend to use the regulator on a breadboard, be careful to avoid installing header pins in a way that shorts EN to PG. The PG connection is the only one not accessible along the edge of the board. **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. | [![](https://core-electronics.com.au/attachments/localcontent/0J13530_12818934989.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13530_144044c84f6.png) | |---| During normal operation, this product can get hot enough to burn you. Take care when handling this product or other components connected to it. This regulator has a protection feature that gracefully limits the output current, which can help protect it from thermal damage in applications loads that exceed the regulator’s capabilities. However, this limiting is insufficient to cover all possible combinations of input voltage, output voltage, and load, so Pololu recommend you take precautions to ensure that the continuously applied loads of your application will not exceed the currents shown in the above graph. If your application has the potential to expose the regulator to higher loads, please consider using additional external protective components such as fuses or circuit breakers. **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. The module’s EN input can be driven low to put the board into a low-power state where it draws approximately 50 µA plus 1 µA per volt on VIN (note that for high input voltages, this current draw can exceed the quiescent current draw of the regulator). | [![](https://core-electronics.com.au/attachments/localcontent/0J13531_12796dd687e.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13531_133336706de.png) | |---| **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 graphs below show the dropout voltages for the different members of this regulator family: | [![](https://core-electronics.com.au/attachments/localcontent/0J13532_7850459ecec.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13532_7826325e8d4.png) | |---| | [![](https://core-electronics.com.au/attachments/localcontent/0J13533_12498d9578e.jpg)](https://core-electronics.com.au/attachments/localcontent/0J13533_14355c0f8ea.png) | |---| **Dimensions** | Size: | 1.0" × 1.0" × 0.43" | |---|---| | Weight: | 6.5 g | **General specifications** | Minimum operating voltage: | 24 V[1](https://core-electronics.com.au/#note1) | |---|---| | Maximum operating voltage: | 60 V | | Continuous output current: | 4 A[2](https://core-electronics.com.au/#note2) | | Output voltage: | 24 V | | Reverse voltage protection?: | Y | | Maximum quiescent current: | 10 mA[3](https://core-electronics.com.au/#note3) | | Output type: | fixed 24V | **Identifying markings** | PCB dev codes: | reg34a | |---|---| | Other PCB markings: | 0J15502, blank white box | **Notes:** 1Subject to dropout voltage considerations. See the dropout voltage graph under the description tab for more information.2Typical continuous output current at 42 V in. Actual achievable continuous output current is a function of input voltage and is limited by thermal dissipation. See the output current graph under the description tab for more information.3While enabled with no load at input voltages approximately equal to or less than the set output voltage. The quiescent current drops under 0.2 mA at higher input voltages or when the board is disabled using the EN pin. See the quiescent current graphs for more information.**File downloads** - **[Dimension diagram of the Step-Down Voltage Regulator D42V55Fx](https://core-electronics.com.au/attachments/localcontent/d42v55fx-step-down-voltage-regulators-dimensions_3188443700f.pdf) (319k pdf)** - **3D model of the Step-Down Voltage Regulator D42V55Fx (6MB step)** - **Drill guide for the Step-Down Voltage Regulator D42V55Fx (44k dxf)** This DXF drawing shows the locations of all of the board’s holes. ## Images - [Product image 1](https://core-electronics.com.au/media/catalog/product/P/O/POLOLU-5579-1.jpg)