SP7650 - 3A 28V Wide-Vin 300kHz Sync Buck Regulator | MaxLinear
MPN: SP7650 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.42 | $3.42 |
| 10 | $3.07 | $30.70 |
| 100 | $2.74 | $274.00 |
| 500 | $2.45 | $1,225.00 |
| 1,000 | $2.18 | $2,180.00 |
SP7650 Overview
A buck regulator (step-down switching regulator) is a power management IC that converts a higher DC input voltage to a lower DC output voltage using high-frequency switching of an inductor and capacitor filter network. Buck regulators sit within the voltage regulator family, which itself falls under the power management IC category of semiconductors. Compared with linear regulators, a synchronous buck achieves high efficiency (typically 90%+) across wide input-to-output differentials because it transfers energy through an inductor rather than dissipating it as heat. The SP7650 belongs to the synchronous buck sub-family, meaning both the high-side and low-side switches are integrated N-channel MOSFETs - eliminating the need for an external Schottky rectifier.
Key differentiators include the wide 2.5V-28V input range, internal soft-start, fixed 300 kHz PWM voltage-mode control, and an MSL-1 rated thermally-enhanced DFN package. Protection features include undervoltage lockout (UVLO), thermal shutdown, and output short-circuit protection. The low-side synchronous switch keeps efficiency high even at light loads, while the 0.8V reference supports modern low-voltage ASIC, FPGA, and DSP cores.
Typical applications include 12V/24V distributed power systems, networking and telecom ASIC rails, industrial point-of-load converters, FPGA core supplies, and general-purpose DC-DC modules. The fixed 300 kHz switching frequency allows predictable EMC behavior and small filter component sizing.
When designing with the SP7650, place the input ceramic bypass capacitor within 5 mm of the PVIN pins to minimize switching loop inductance. Use a low-ESR output capacitor of 22uF or larger to limit ripple below 1% of VOUT, and ensure the exposed pad receives at least 2 square centimeters of copper for thermal dissipation.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet alone, providing an actionable engineering reference for sourcing the SP7650 today.
Drop-in alternatives for SP7650 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
SP7650ER-L
✅ Drop-In📋 Reference alternative (not in catalog)
SP7650ER
✅ Drop-In📋 Reference alternative (not in catalog)
SP7650 Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Step-Down (Buck) |
| Input Voltage Range | 2.5 V to 28 V |
| Output Current | 3 A |
| Switching Frequency | 300 kHz (fixed) |
| Reference Voltage | 0.8 V |
| Control Method | PWM Voltage Mode |
| Built-in Power Switches | Yes (low RDS(on), integrated) |
| Package | 26-Pin PowerVFDFN |
| Mounting Type | Surface Mount |
| MSL Level | 1 |
| RoHS Status | Compliant |
| Key Protections | UVLO, Thermal Shutdown, Output Short-Circuit Protection |
SP7650 Pin Configuration
| Pin 1 | PGND — Power ground return for internal switches |
| Pin 2 | PGND — Power ground return for internal switches |
| Pin 3 | PVIN — Power input to high-side switch |
| Pin 4 | PVIN — Power input to high-side switch |
| Pin 5 | VCC — Internal 5V regulator bypass/return |
| Pin 6 | NC — Not connected (per datasheet) |
| Pin 7 | NC — Not connected (per datasheet) |
| Pin 8 | NC — Not connected (per datasheet) |
| Pin 9 | BOOT — Bootstrap capacitor for high-side drive |
| Pin 10 | LX — Switching node to external inductor |
| Pin 11 | LX — Switching node to external inductor |
| Pin 12 | FB — Feedback input from output resistor divider |
| Pin 13 | COMP — Compensation network connection |
| Pin 14 | EN — Active-high enable input |
| Pin 15 | SS — Soft-start capacitor connection |
| Pin 16 | NC — Not connected (per datasheet) |
| Pin 17 | NC — Not connected (per datasheet) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | AGND — Analog ground (single-point tie to PGND) |
| Pin 20 | PVIN — Power input to high-side switch |
| Pin 21 | PVIN — Power input to high-side switch |
| Pin 22 | PGND — Power ground return for internal switches |
| Pin 23 | PGND — Power ground return for internal switches |
| Pin 24 | NC — Not connected (per datasheet) |
| Pin 25 | NC — Not connected (per datasheet) |
| Pin 26 | PGND — Power ground return for internal switches (exposed pad) |
Typical Applications
SP7650 is suitable for 6 applications: 12V Distributed Power Bus Converter, 24V Industrial Point-of-Load Supply, Networking ASIC and Router Power Rails, FPGA Core and Logic Voltage Supply, Telecom and Server DC-DC Modules, Automotive Infotainment Power Subsystems.
12V Distributed Power Bus Converter
The SP7650's 2.5 V to 28 V input range accepts 12 V distributed power bus voltages directly and steps them down to ASIC or FPGA core voltages as low as 0.8 V. Its fixed 300 kHz switching frequency pairs well with standard 22uF output capacitors to keep ripple below 30 mV at 3 A load. The synchronous topology achieves >92% efficiency at 12 V to 3.3 V conversion, reducing thermal stress versus a linear regulator in space-constrained equipment.
Recommended
24V Industrial Point-of-Load Supply
The SP7650 is specifically designed for 24 V industrial distributed systems and tolerates up to 28 V continuous input, with internal UVLO protecting against brown-out conditions. The integrated synchronous switches eliminate the external Schottky diode, reducing PCB area and BOM cost. Its 26-pin PowerVFDFN package with exposed pad dissipates up to 2.5 W at 1 A continuous load with 1 sq-inch copper, suitable for industrial PLC and motor control subsystems.
Recommended
Networking ASIC and Router Power Rails
Networking ASICs and switch-fabric chips require sub-1V supply rails with tight regulation, which the SP7650 provides via its 0.8V internal reference and PWM voltage-mode control. The fixed 300 kHz operation produces predictable EMI harmonics that simplify FCC Class B compliance testing. Its 3 A output drives multi-core networking processors and SERDES PHYs while the integrated soft-start avoids inrush-triggered rail droop during power-up sequencing.
Recommended
FPGA Core and Logic Voltage Supply
The SP7650's 3 A output and 0.8V reference cover modern FPGA core supply requirements (typically 0.85V to 1.2V) set by external resistor dividers. Its fixed 300 kHz frequency avoids the beat-frequency interactions seen between variable-frequency regulators and FPGA PLLs, stabilizing PLLs and high-speed SERDES on board. The exposed-pad PowerVFDFN package allows the part to sit within 25 mm of the FPGA decoupling network with minimal trace inductance.
Recommended
Telecom and Server DC-DC Modules
The SP7650's 28 V input tolerates telecom -48 V systems rectified to roughly +54 V and dropped through a front-end converter to +24 V, making it suitable for intermediate bus converters in card cages. Its 300 kHz switching frequency and small 26-pin PowerVFDFN footprint support high-density SMD module layouts where PCB real estate is at a premium. The integrated thermal shutdown and short-circuit protection allow the module to ride through fault events without propagating damage to upstream supplies.
Recommended
Automotive Infotainment Power Subsystems
Although not AEC-Q100 qualified, the SP7650 is widely used in non-safety automotive infotainment sections where 12V battery and 24V truck bus voltages must be regulated for head-unit processors and display controllers. Its 28 V input handles load-dump transients above 24 V when preceded by a TVS clamp, and the internal synchronous switches limit power dissipation during cold-crank conditions. The compact PowerVFDFN package fits inside tight dashboard PCB stacks.
Recommended
Recommended Products Summary
Engineering reference data for SP7650 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SP7650ER-L | SP7650ER |
|---|---|---|---|
| Package | 26-Pin PowerVFDFN | 26-Pin PowerVFDFN - same | 26-Pin PowerVFDFN - same |
| Brand | MaxLinear | MaxLinear - same | Rochester Electronics (Sipex legacy) |
| Input Voltage Range | 2.5 V to 28 V | 2.5 V to 28 V | 2.5 V to 28 V |
| Output Current | 3 A | 3 A | 3 A |
| Switching Frequency | 300 kHz (fixed) | 300 kHz (fixed) | 300 kHz (fixed) |
| Synchronous Switches | Yes (integrated) | Yes (integrated) | Yes (integrated) |
| Terminal Finish | Matte Sn (lead-free) | Matte Sn (lead-free) | SnPb (leaded, legacy) |
| Lifecycle | Active (MaxLinear) | Active | Sustained (Rochester Electronics) |
Key Differentiators
- Wide input range from dual-input 5V bias architecture (vs SP7650ER-L)
- Drop-in compatible alternate supply source (vs SP7650ER)
- Internal synchronous switches eliminate external Schottky (vs SP7650ER-L)
Design Notes
Estimated: at VIN = 24 V, VOUT = 5 V, IOUT = 3 A (efficiency ~ 92%), internal dissipation is approximately 1.3 W. The 26-pin PowerVFDFN's exposed pad provides the only thermal path; with at least 2 square centimeters of copper on top and bottom layers, theta_JA drops below 40 C/W, keeping junction rise below 55 C above 25 C ambient. Without copper spreading, junction temperature may exceed 125 C at full load - always provision the exposed pad.
Place the input ceramic bypass capacitor (typically 22uF X5R 35V) within 5 mm of the PVIN pins and the BOOT capacitor (typically 0.1uF) directly between BOOT and LX pins. The switching loop PVIN-to-LX-to-PGND must be minimized to reduce ringing; use a wide power-ground copper pour directly under the IC. A low-ESR ceramic output capacitor of 22uF or larger limits peak-to-peak output ripple below 30 mV at 3 A load.
Do not connect the VCC pin to PVIN - the SP7650 provides internal bias from PVIN, and external VCC injection is not supported in standard applications. Avoid floating the EN pin; tie it to a logic source or PVIN via a 100 kOhm resistor to ensure predictable startup. The COMP pin compensation network is critical for loop stability - use the values recommended in the datasheet's typical application circuit and do not exceed 5x the recommended C_COMP value, or the part may oscillate.
Compliance Information
RoHS compliant per MaxLinear product page (SP7650ER-L is lead-free). Original SP7650ER (Sipex-era) may be SnPb leaded finish. Not AEC-Q100 qualified - not intended for automotive safety applications.
