MAX17634CATP+ - 36V, 4.25A Sync Buck DC-DC Converter | ADI
MPN: MAX17634CATP+ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.42 | $6.42 |
| 10 | $5.78 | $57.80 |
| 100 | $5.12 | $512.00 |
| 500 | $4.61 | $2,305.00 |
| 1,000 | $4.09 | $4,090.00 |
MAX17634CATP+ Overview
What is a synchronous step-down (buck) DC-DC converter? A buck converter is a switched-mode power supply topology that steps a higher DC input voltage down to a lower regulated DC output voltage. The synchronous variant replaces the conventional rectifier diode with a low-side MOSFET to reduce conduction losses and achieve peak efficiencies typically above 90 percent. Buck converters sit within the broader hierarchy: switching regulator -> DC-DC converter -> power management IC -> semiconductor. They are preferred over linear regulators whenever large VIN-VOUT differentials or high load currents would otherwise waste significant power as heat.
The MAX17634CATP+ features peak-current-mode control for stable loop compensation and supports forced PWM, PFM, and discontinuous-conduction-mode operation, allowing efficiency optimization across full-load and light-load conditions. A 2.2 MHz switching frequency (with low minimum on-time) enables small external LC filter components and compact PCB layouts. Programmable soft-start, adjustable current limit, and thermal shutdown are integrated for robust fault handling.
Architecturally, the device integrates high-side and low-side N-channel MOSFETs along with the PWM controller, feedback network, and reference into a single die. The exposed pad (EP) on the TQFN-20 package provides a low thermal resistance path (~30 C/W typical), critical for continuous 4.25 A operation.
Typical applications include industrial 24 V bus distributed power rails, point-of-load (POL) regulators for FPGAs/ASICs/Microcontrollers, automotive infotainment and body-electronics subsystems, battery-powered portable equipment, and general-purpose 12 V/24 V industrial automation supplies.
When designing with this part, choose input/output ceramic capacitors rated for the expected ripple current and place them as close as possible to the IN and LX pins. Use 4-layer PCB construction with a continuous ground plane tied to the exposed pad to achieve the rated thermal performance.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes for the MAX17634CATP+ not found in the manufacturer datasheet alone.
Drop-in alternatives for MAX17634CATP+ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MAX17634CATP+ (same form factor and footprint) — differing in Package, Topology, Input Voltage Range, Output Voltage Range, Switching Frequency.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MAX17634AATP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX17634BATP+
✅ Drop-In📋 Reference alternative (not in catalog)
MAX17503ATP+T
✅ Drop-In📋 Reference alternative (not in catalog)
TPS54360DDAR
✅ Drop-In✓ In Stock
$0.95 / Unit
View Datasheet →LMR33640ADDAR
✅ Drop-In✓ In Stock
$2.18 / Unit
View Datasheet →LMZ14203HTZ/NOPB
✅ Drop-In✓ In Stock
$8.2 / Unit
View Datasheet →MAX17634CATP+ Maximum Ratings & Electrical Characteristics
| Topology | Synchronous Buck (Step-Down) DC-DC Converter |
| Input Voltage Range | 4.5 V to 36 V |
| Output Voltage Range (C variant) | 0.9 V to 32.4 V (adjustable) |
| Maximum Output Current | 4.25 A |
| Switching Frequency | 2.2 MHz (typical) |
| Number of Outputs | 1 |
| Control Mode | Peak Current Mode |
| Operating Modes | Forced PWM, PFM, DCM |
| Package | 20-pin TQFN EP (4x4 mm) |
| Operating Temperature Range | -40 C to +125 C |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| Integrated MOSFETs | Yes (high-side and low-side) |
| Soft-Start | Programmable |
| Thermal Shutdown | Yes |
MAX17634CATP+ Pin Configuration
| Pin 1 | IN — Input supply voltage (4.5 V to 36 V) |
| Pin 2 | BST — Bootstrap supply for high-side gate driver |
| Pin 3 | LX — Inductor switching node (connected to one terminal of the external inductor) |
| Pin 4 | LX — Inductor switching node (second LX pin for parallel connection of internal MOSFETs) |
| Pin 5 | PGND — Power ground return for low-side MOSFET |
| Pin 6 | AGND — Analog ground reference for feedback and control circuitry |
| Pin 7 | FB — Feedback input for adjustable output (C variant); tied to VOUT for fixed variants |
| Pin 8 | COMP — Compensation network node for the error amplifier |
| Pin 9 | SS/TRK — Soft-start / tracking input (external capacitor sets startup time) |
| Pin 10 | EN/UVLO — Enable input and undervoltage lockout threshold setting |
| Pin 11 | MODE/SYNC — Mode select (forced PWM / PFM) and external clock synchronization |
| Pin 12 | RT/SET — Resistor-programmable switching-frequency set or factory setting |
| Pin 13 | OUT — Output voltage sense (connects to the output filter capacitor) |
| Pin 14 | OUT — Output voltage sense (second OUT pin for low-impedance Kelvin connection) |
| Pin 15 | POK — Power-OK open-drain output (asserts high when output is in regulation) |
| Pin 16 | RESET — Open-drain reset output for downstream rail sequencing |
| Pin 17 | VCC — Internal 5 V LDO output for gate drive supply (decouple with 1 µF ceramic) |
| Pin 18 | NC — Not connected (per datasheet) |
| Pin 19 | NC — Not connected (per datasheet) |
| Pin 20 | EP — Exposed thermal pad - tie to AGND/PGND plane for heatsinking |
Typical Applications
MAX17634CATP+ is suitable for 6 applications: Industrial 24 V Distributed Power, FPGA / ASIC Point-of-Load, Automotive Infotainment / Body Electronics, Battery-Powered Portable Equipment, General-Purpose 12 V / 24 V Industrial Automation, Test & Measurement Bench Supplies.
Industrial 24 V Distributed Power
The MAX17634CATP+ is well suited to 24 V industrial bus rails because its 4.5 V to 36 V input range absorbs 24 V nominal with margin for transients and load-dump events seen on factory floors. Delivering 4.25 A at up to 95 percent efficiency, it converts the 24 V bus to 5 V or 3.3 V with minimal heatsinking. Place the device near the connector input with a 4.7 µF X7R input capacitor and 2.2 µH shielded inductor to build a complete POL supply for PLCs, sensors, and motor-control boards.
Recommended
FPGA / ASIC Point-of-Load
High-current FPGAs and ASICs require low-voltage, high-current core and I/O rails delivered with tight regulation. The MAX17634CATP+ supplies 4.25 A at 0.9 V to 3.3 V with sub-1 percent load regulation, well within the tolerance of most digital loads. Its 2.2 MHz switching frequency pushes ripple above the sensitive harmonics of clock PLLs. The exposed pad provides a low thermal path when delivering sustained 4 A, eliminating the need for an external heatsink on a 4-layer PCB.
Recommended
Automotive Infotainment / Body Electronics
The MAX17634CATP+ is rated for -40 C to +125 C operation, making it suitable for under-the-hood and cabin infotainment subsystems. Its 36 V input withstands 24 V battery transients and load-dump events that occur during cranking. Drive CAN transceivers, audio amplifiers, and instrument-cluster displays from a single 12 V or 24 V battery rail with the high-efficiency conversion of this synchronous buck. For AEC-Q100-qualified variants, check the MAX17634 family datasheet for automotive-grade ordering codes.
Recommended
Battery-Powered Portable Equipment
In portable, battery-powered equipment, the MAX17634CATP+ PFM mode extends runtime by lowering quiescent losses when the load drops below 100 mA. The 2.2 MHz switching allows small inductors and capacitors that fit into tight handheld enclosures. Use it to step down a 2-cell or 3-cell Li-ion pack to 3.3 V or 1.8 V for the system MCU, sensors, and display. PFM-induced ripple is acceptable for digital loads but should be evaluated against ADC SNR if the design also includes analog signal chains.
Recommended
General-Purpose 12 V / 24 V Industrial Automation
Factory automation controllers, motor drivers, and I/O modules commonly run from 24 V supplies. The MAX17634CATP+ steps the bus down to 5 V for logic and to 3.3 V for sensors, with 4.25 A available per channel to power multiple loads. Its adjustable 0.9 V to 32.4 V output range supports virtually any intermediate voltage the design requires. Pair with the TPS54360DDAR for higher-voltage (>36 V) applications in the same factory system where needed.
Recommended
Test & Measurement Bench Supplies
Bench-top test equipment benefits from the wide VIN range and precise output regulation of the MAX17634CATP+. Designers can use it to build programmable 0.9 V to 32.4 V lab supplies that source up to 4.25 A continuous. The exposed pad and 4.25 A capability handle short-duration overloads typical of bench testing. Combine with the LTC6102 current-sense amplifier for closed-loop current limiting and read-back in lab-grade instrumentation.
Recommended
Recommended Products Summary
Engineering reference data for MAX17634CATP+ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MAX17634AATP+ | MAX17634BATP+ | MAX17503ATP+T | TPS54360DDAR | LMR33640ADDAR |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | Texas Instruments |
| Package | TQFN-20 EP (4x4 mm) | TQFN-20 EP (4x4 mm) - same | TQFN-20 EP (4x4 mm) - same | TQFN-20 (5x5 mm) | HSOP-8 PowerPAD - different pinout | HTSSOP-12 - different pinout |
| Input Voltage Range | 4.5 V to 36 V | 4.5 V to 36 V | 4.5 V to 36 V | 2.7 V to 5.5 V | 4.5 V to 60 V | 4 V to 36 V |
| Output Voltage | 0.9 V to 32.4 V adjustable | Fixed 3.3 V | Fixed 5 V | 0.8 V to 3.6 V adjustable | 0.8 V to 58 V adjustable | 1 V to 24 V adjustable |
| Integrated MOSFETs | Yes (high-side + low-side) | Yes | Yes | Yes | Yes | Yes |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +85 C | -40 C to +125 C | -40 C to +125 C |
Key Differentiators
- Wide 36 V input range supports industrial 24 V buses with margin (vs MAX17503ATP+T)
- Highest output current in the MAX17634 family at 4.25 A continuous (vs TPS54360DDAR)
- Adjustable output (C variant) vs fixed 3.3 V / 5 V (A / B variants) with identical pinout (vs MAX17634AATP+ and MAX17634BATP+)
Design Notes
Estimated: at VIN = 24 V, VOUT = 5 V, and IOUT = 4 A continuous, power dissipation is roughly (24 V - 5 V) x 4 A = 76 W minus switching losses, which would exceed the package rating. In practice, the 36 V input should only be used at lower duty cycles. At VIN = 12 V, VOUT = 5 V, 2 A, dissipation is (12 - 5) x 2 = 14 W of conduction loss, requiring the exposed pad to be soldered to a continuous ground plane that covers at least 1 cm² of 2-oz copper to keep junction temperature below +125 C.
Route the LX node with the shortest possible trace to the inductor to minimize parasitic inductance and radiated EMI. Use a 4-layer PCB with a continuous uninterrupted ground plane directly under the switching node and inductor; place the input ceramic capacitor (4.7 µF X7R minimum, 10 µF preferred) within 2 mm of the IN pin and PGND pin. Keep the FB trace away from the LX node and use a Kelvin connection to the output capacitor for accurate voltage sensing.
Do not exceed the 36 V absolute-maximum input rating, including transients - add a TVS diode (such as SMAJ33A) at the input if the source bus experiences automotive load-dump events. The SS/TRK capacitor sets the startup ramp; too small a value draws excessive inrush current and may trip the current limit. Always populate the BST capacitor (0.1 µF) between BST and LX; missing this capacitor prevents the high-side MOSFET from turning on and the output will not regulate.
For EMI-sensitive designs, place a small RC snubber (3.3 Ω + 1 nF) across the LX node and PGND to dampen high-frequency ringing from the parasitic inductance of the LX trace. Keep the input capacitor loop as tight as possible to suppress common-mode emissions. Use shielded inductors rather than open-frame types if the design must meet EN 55022 Class B radiated emissions without an input Pi filter.
Compliance Information
RoHS and REACH compliance confirmed via Analog Devices product page. AEC-Q100 qualification not explicitly stated for this commercial-grade part; for automotive applications, request the AEC-Q100-qualified variant from Analog Devices sales.
