{"product_id":"2854-pololu-9v-2-5a-step-down-voltage-regulator-d24v25f9","title":"Pololu 9V, 2.5A Step-Down Voltage Regulator D24V25F9","description":"\u003cp\u003eThis small synchronous switching step-down (or buck) regulator takes an input voltage of up to 38 V and efficiently reduces it to \u003cstrong\u003e9 V\u003c\/strong\u003e.  The board measures only 0.7″ × 0.7″, but it allows a typical continuous output current of up to \u003cstrong\u003e2.5 A\u003c\/strong\u003e.   Typical efficiencies of 85% to 95% make this regulator well suited for powering moderate loads like sensors or small motors.  High efficiencies are maintained at light loads by dynamically changing the switching frequency, and an optional shutdown pin enables a low-power state with a current draw of a few hundred microamps.\u003c\/p\u003e\n\u003cbr\u003e\u003ch2\u003eOverview\u003c\/h2\u003e\n\u003cp class=\"note_warning\"\u003e\u003cstrong\u003eDecember 2022 availability update:\u003c\/strong\u003e Availability of this product is still restricted by the global parts shortages.  For applications that do not specifically require these D24V25Fx regulators, we recommend our newer \u003ca href=\"https:\/\/www.pololu.com\/category\/192\/d24v22fx-step-down-voltage-regulators\"\u003eD24V22Fx family of step-down regulators\u003c\/a\u003e, which have a similar input voltage range, output current, and size.\u003c\/p\u003e\n\u003ctable class=\"picture_with_caption right\"\u003e\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J10003.1200.jpg?0a1aed3568c8f883cb50a5246ada2265\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id step-down voltage regulator d24v25f5 or d24v25f3 top view with dimensions. data-picture-id=\"0J10003\" data-picture-longest_side=\"1071\" src=\"https:\/\/a.pololu-files.com\/picture\/0J10003.300.jpg?0a1aed3568c8f883cb50a5246ada2265\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\u003c\/table\u003e\n\u003cp\u003eThe D24V25Fx family of step-down voltage regulators generates lower output voltages from input voltages as high as 38 V.  They are switching regulators (also called switched-mode power supplies (SMPS) or DC-to-DC converters) with typical efficiencies between 85% and 95%, which is much more efficient than linear voltage regulators, especially when the difference between the input and output voltage is large.  The available output current is a function of the input voltage and efficiency (see the \u003cem\u003eTypical efficiency and output current\u003c\/em\u003e section below), but the output current can typically be as high as 2.5 A.\u003c\/p\u003e\n\u003cp\u003eAt light loads, the switching frequency automatically changes to maintain high efficiencies.  These regulators have a typical quiescent (no load) current draw of less than 1 mA, and the ENABLE pin can be used to put the boards in a low-power state that reduces the quiescent current to approximately 10 µA to 20 µA per volt on VIN.\u003c\/p\u003e\n\u003cp\u003eThe modules have built-in reverse-voltage protection, short-circuit protection, a thermal shutdown feature that helps prevent damage from overheating, and a soft-start feature that reduces inrush current.\u003c\/p\u003e\n\u003cp\u003eSeveral different fixed output voltages are available:\u003c\/p\u003e\n\u003cp\u003eAlternatives available with variations in these parameter(s):\n\u003ca class=\"select_by_specification_link\" data-lightbox-link=\"true\" data-lightbox-height=\"20rem\" data-lightbox-width=\"50rem\" href=\"\/catalog\/select-by-specification?parameters=0J130\u0026amp;product=2854\u0026amp;products=2850\"\u003e\u003cspan class=\"select_by_specification_parameter\"\u003eoutput voltage\u003c\/span\u003e\n\u003cspan class=\"select_by_specification_main_link\"\u003eSelect variant…\u003c\/span\u003e\n\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003eThe different voltage versions of this regulator all look very similar, so you should consider adding your own distinguishing marks or labels if you will be working simultaneously with multiple versions.  This product page applies to all versions of the D24V25Fx family.\u003c\/p\u003e\n\u003cp class=\"note\"\u003eFor newer step-down regulators with a similar input voltage range, output current, and size, consider the \u003ca href=\"https:\/\/www.pololu.com\/category\/192\/d24v22fx-step-down-voltage-regulators\"\u003eD24V22Fx family of regulators\u003c\/a\u003e.  Please note that while these D24V22Fx  regulators look very similar to the D24V25Fx family of regulators, they do not have the same pinout and are based on a different internal design, so there are fundamental differences in operation.  The D24V22Fx family also includes a 12 V option while the D24V25Fx family does not.\u003c\/p\u003e\n\u003cp\u003eFor higher-power applications, we carry a slightly larger, pin-compatible, 5 V version of this regulator that has a \u003ca href=\"https:\/\/www.pololu.com\/product\/2851\"\u003etypical maximum output current of 5 A\u003c\/a\u003e.\u003c\/p\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\n\u003ctr\u003e\n\u003ctd style=\"max-width: 450px\"\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J10001.1200.jpg?9ce5d6be636923638558abe5649c7677\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id comparison of the d24v25fx and d24v50f5 step-down voltage regulators. data-picture-id=\"0J10001\" data-picture-longest_side=\"1200\" src=\"https:\/\/a.pololu-files.com\/picture\/0J10001.450.jpg?9ce5d6be636923638558abe5649c7677\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003cth style=\"max-width: 450px\"\u003e\u003cp\u003eSide-by-side comparison of the 2.5 A D24V25Fx (left) and 5 A D24V50F5 (right) step-down voltage regulators.\u003c\/p\u003e\u003c\/th\u003e\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003cp\u003eTwo even larger, higher-power, 5 V versions of this regulator are also available: one with a \u003ca href=\"https:\/\/www.pololu.com\/product\/2865\"\u003etypical maximum output current of 6 A\u003c\/a\u003e, and the other with a \u003ca href=\"https:\/\/www.pololu.com\/product\/2866\"\u003etypical maximum output current of 9 A\u003c\/a\u003e.  The higher-power versions also have a few additional features, like a “power good” signal and the ability to lower their output voltage, and they include optional terminal blocks for easy removable connections.\u003c\/p\u003e\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n\t\u003cli\u003eInput voltage:\n\t\u003cul\u003e\n\t\t\u003cli\u003e4.5 V to 38 V for the version that outputs 3.3 V\u003c\/li\u003e\n\t\t\u003cli\u003e[\u003ci\u003eoutput voltage + dropout voltage\u003c\/i\u003e] to 38 V for output voltages of 5 V and higher (see below for more information on dropout voltage)\u003c\/li\u003e\n\t\u003c\/ul\u003e\n\u003c\/li\u003e\n\t\u003cli\u003eFixed 3.3 V, 5 V, 6 V, 7.5 V, or 9 V output (depending on regulator version) with 4% accuracy\u003c\/li\u003e\n\t\u003cli\u003eTypical maximum continuous output current: 2.5 A\u003c\/li\u003e\n\t\u003cli\u003eIntegrated reverse-voltage protection, over-current and short-circuit protection, over-temperature shutoff, and soft-start\u003c\/li\u003e\n\t\u003cli\u003eTypical efficiency of 85% to 95%, depending on input voltage and load; the switching frequency automatically changes at light loads to maintain high efficiencies\u003c\/li\u003e\n\t\u003cli\u003eTypical no-load quiescent current under 1 mA; can be reduced to 10 µA to 20 µA per volt on VIN by disabling the board\u003c\/li\u003e\n\t\u003cli\u003eCompact size:  0.7″ × 0.7″ × 0.35″ (17.8 mm × 17.8 mm × 9 mm)\u003c\/li\u003e\n\t\u003cli\u003eTwo 0.086″ mounting holes for #2 or M2 \u003ca href=\"https:\/\/www.pololu.com\/category\/101\/nuts-and-screws\"\u003escrews\u003c\/a\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eUsing the regulator\u003c\/h2\u003e\n\u003ch3\u003eConnections\u003c\/h3\u003e\n\u003cp\u003eThis buck regulator has five connection points for four different connections: enable (EN), input voltage (VIN), 2x ground (GND), and output voltage (VOUT).\u003c\/p\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J10080.1200.jpg?b1480493bed2ee7a3e48980aaf0e485c\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id step-down voltage regulator d24v25f5 or d24v25f3 top view with labeled pinout. data-picture-id=\"0J10080\" data-picture-longest_side=\"1200\" src=\"https:\/\/a.pololu-files.com\/picture\/0J10080.300.jpg?b1480493bed2ee7a3e48980aaf0e485c\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\u003c\/table\u003e\n\u003cp\u003eThe input voltage, \u003cstrong\u003eVIN\u003c\/strong\u003e, powers the regulator.  Voltages between 4.5 V and 38 V can be applied to VIN, but for versions of the regulator that have an output voltage higher than 4.5 V, 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 dropout voltages as a function of the load).\u003c\/p\u003e\n\u003cp\u003eThe output voltage, \u003cstrong\u003eVOUT\u003c\/strong\u003e, is fixed and depends on the regulator version: the D24V25F3 version outputs 3.3 V, the D24V25F5 version outputs 5 V, the D24V25F6 version outputs 6 V, the D24V25F7 version outputs 7.5 V, and the D24V5F9 version outputs 9 V.\u003c\/p\u003e\n\u003cp\u003eThe regulator is enabled by default: a 100 kΩ pull-up resistor on the board connects the \u003cstrong\u003eENABLE\u003c\/strong\u003e pin to reverse-protected VIN.  The ENABLE pin can be driven low (under 0.6 V) to put the board into a low-power state.  The quiescent current draw in this sleep mode is dominated by the current in the pull-up resistor from ENABLE to VIN and by the reverse-voltage protection circuit, which will draw between 10 µA and 20 µA per volt on VIN when ENABLE is held low.  If you do not need this feature, you should leave the ENABLE pin disconnected.\u003c\/p\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\n\u003ctr\u003e\n\u003ctd style=\"max-width: 301px\"\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J10002.1200.jpg?3998abc2e3c95a083f91160c19a3dd8c\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id step-down voltage regulator d24v25f5 or d24v25f3 with included hardware. data-picture-id=\"0J10002\" data-picture-longest_side=\"1200\" src=\"https:\/\/a.pololu-files.com\/picture\/0J10002.301.jpg?3998abc2e3c95a083f91160c19a3dd8c\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003cth style=\"max-width: 301px\"\u003e\u003cp\u003ePololu 2.5 A Step-Down Voltage Regulator D24V25F5 (5 V) or D24V25F3 (3.3 V) with included hardware.\u003c\/p\u003e\u003c\/th\u003e\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003cp\u003eThe five connection points are labeled on the top of the PCB and are arranged with a 0.1″ spacing for compatibility with solderless \u003ca href=\"https:\/\/www.pololu.com\/category\/28\/solderless-breadboards\"\u003ebreadboards\u003c\/a\u003e, \u003ca href=\"https:\/\/www.pololu.com\/category\/19\/connectors\"\u003econnectors\u003c\/a\u003e, and other prototyping arrangements that use a 0.1″ grid.  Either the included 5×1 \u003ca href=\"https:\/\/www.pololu.com\/product\/965\"\u003estraight male header strip\u003c\/a\u003e or the 5×1 \u003ca href=\"https:\/\/www.pololu.com\/product\/967\"\u003eright angle male header strip\u003c\/a\u003e can be soldered into these holes.  For the most compact installation, you can solder wires directly to the board.\u003c\/p\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\n\u003ctr\u003e\n\u003ctd style=\"max-width: 450px\"\u003e\u003cimg alt=\"\" class=\"\" data-gallery-pictures=\"[{\" id step-down voltage regulator d24v25fx side view. data-picture-id=\"0J5778\" data-picture-longest_side=\"1200\" src=\"https:\/\/a.pololu-files.com\/picture\/0J5778.450.jpg?5e28bd83a833c11a0386edc965d4f15b\"\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\u003cth style=\"max-width: 450px\"\u003e\u003cp\u003ePololu 2.5A Step-Down Voltage Regulator D24V25Fx, side view.\u003c\/p\u003e\u003c\/th\u003e\u003c\/tr\u003e\n\u003c\/table\u003e\n\u003cp\u003eThe board has two 0.086″ mounting holes intended for #2 or M2 \u003ca href=\"https:\/\/www.pololu.com\/category\/101\/nuts-and-screws\"\u003escrews\u003c\/a\u003e.  The mounting holes are at opposite corners of the board and are separated by 0.53″ both horizontally and vertically.\u003c\/p\u003e\n\u003ch3\u003eTypical efficiency and output current\u003c\/h3\u003e\n\u003cp\u003eThe 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.  This family of switching regulators typically has an efficiency of 85% to 95%, though the actual efficiency in a given system depends on input voltage, output voltage, and output current.  See the efficiency graph near the bottom of this page for more information.\u003c\/p\u003e\n\u003cp\u003eThe maximum achievable output current is typically around 2.5 A, but this depends on many factors, including the ambient temperature, air flow, heat sinking, and the input and output voltage.\u003c\/p\u003e\n\u003ch3\u003eTypical dropout voltage\u003c\/h3\u003e\n\u003cp\u003eThe 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.  See the “Details” section below for more information on the dropout voltage for this specific regulator version.\u003c\/p\u003e\n\u003ch3\u003eSwitching frequency and behavior under light loads\u003c\/h3\u003e\n\u003cp\u003eThe regulator generally operates at a switching frequency of around 600 kHz, but the frequency drops when encountering a light load to improve efficiency.  This could make it harder to filter out noise on the output caused by switching.\u003c\/p\u003e\n\u003ch2\u003e\nDetails for item #2854\n\u003c\/h2\u003e\n\u003cp\u003eThe graphs below show the typical efficiency and dropout voltage of the 9 V D24V25F9 regulator as a function of the output current:\u003c\/p\u003e\n\u003cdiv class=\"left\"\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J6086.1200.png?4c706b59eeda850326cd98a56873579a\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id efficiency of pololu step-down voltage regulator d24v25f9. data-picture-id=\"0J6086\" data-picture-longest_side=\"600\" src=\"https:\/\/a.pololu-files.com\/picture\/0J6086.450.jpg?4c706b59eeda850326cd98a56873579a\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"left\"\u003e\n\u003ctable class=\"picture_with_caption center\"\u003e\u003ctr\u003e\n\u003ctd\u003e\u003ca href=\"https:\/\/a.pololu-files.com\/picture\/0J6087.1200.png?eaec982923e228de4b6cbbb7f8d0496d\" class=\"noscript-fallback\"\u003e\u003cimg alt=\"\" class=\"zoomable\" data-gallery-pictures=\"[{\" id dropout voltage of pololu step-down regulator d24v25f9. data-picture-id=\"0J6087\" data-picture-longest_side=\"600\" src=\"https:\/\/a.pololu-files.com\/picture\/0J6087.450.jpg?eaec982923e228de4b6cbbb7f8d0496d\"\u003e\u003c\/a\u003e\u003c\/td\u003e\n\u003cp\u003e\u003c\/p\u003e\n\u003c\/tr\u003e\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp class=\"clear note_warning\"\u003eDuring normal operation, this product can get hot enough to burn you. Take care when handling this product or other components connected to it.\u003cbr\u003e\u003cbr\u003eThe over-current limit of the regulator operates on a combination of current and temperature: the current threshold decreases as the regulator temperature goes up.  However, there might be some operating points at low input voltages and high output currents (well over 2.5 A) where the current is just under the limit and the regulator might not shut off before damage occurs.  If you are using this regulator in an application where the input voltage is near the lower limit and the load could exceed 3.5A for sustained periods (more than five seconds), consider using additional protective components such as fuses or circuit breakers.\u003c\/p\u003e","brand":"Pololu","offers":[{"title":"2-4 Settimane","offer_id":47696616751449,"sku":"POL-2854","price":27.74,"currency_code":"EUR","in_stock":true},{"title":"1 Giorno","offer_id":47885969752409,"sku":"POL-2854\/A","price":27.74,"currency_code":"EUR","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0781\/1009\/7753\/files\/0J6091.1200.jpg?v=1705454767","url":"https:\/\/robot-italy.com\/products\/2854-pololu-9v-2-5a-step-down-voltage-regulator-d24v25f9","provider":"Robot Italy","version":"1.0","type":"link"}