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Analog Devices Inc./Maxim Integrated MAX17551AUB+
- Part No.:
- MAX17551AUB+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
MAX17551AUB+.pdf
- Description:
- IC REG BUCK ADJ 50MA 10UMAX
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
The MAX17551AUB+ from Maxim Integrated is a high-efficiency, synchronous step-down DC-DC converter with integrated MOSFETs, operating from 4V to 60V input and delivering up to 50mA output current. It supports adjustable output voltages from 0.8V to 0.9 × VIN, achieves ±1.75% FB voltage accuracy over –40°C to +125°C, and features peak-current-mode control with selectable PWM or PFM operation. It is widely used in industrial sensors and HVAC control systems where compact size and ultra-low quiescent current are critical.
For engineers reviewing the MAX17551AUB+ datasheet, MAX17551AUB+ pinout, MAX17551AUB+ application, or MAX17551AUB+ equivalent, key selection criteria include its 22µA no-load supply current, 100kHz–2.2MHz programmable switching frequency, internal compensation for any output voltage, monotonic startup into prebiased loads, and robust protection features including peak current limit, thermal shutdown, and output voltage monitoring via open-drain RESET.
Technical Context
The MAX17551AUB+ employs an internally compensated peak-current-mode control architecture with fixed internal slope compensation. Its high-side pMOS and low-side nMOS switches are fully integrated, eliminating external Schottky diodes and enabling all-ceramic capacitor designs. The error amplifier compares FB voltage against a 0.8V reference (±1.75% over temperature), and the PWM comparator determines on-time using current-sense and slope signals.
Operation mode is selected via the MODE pin: unconnected enables automatic PFM at light loads (IPFM = 39mA typ), while grounding forces constant-frequency PWM across all loads. EN/UVLO provides programmable undervoltage lockout (1.25V rising threshold), and RT/SYNC accepts either a timing resistor (100kHz–2.2MHz) or external clock synchronization (1.1×fSW, min 40ns off-time) - but only in PWM mode.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 60V - supports wide industrial input rails including 12V, 24V, 36V, 48V, and 60V battery or bus supplies. |
| Output Current | Up to 50mA - sufficient for powering microcontrollers, sensors, and analog front-ends in space-constrained systems. |
| No-Load Supply Current | 22µA in PFM mode - enables multi-year battery life in always-on remote sensor nodes. |
| Feedback Accuracy | ±1.75% over –40°C to +125°C - ensures stable regulation across full industrial ambient range without calibration. |
| Switching Frequency Range | 100kHz to 2.2MHz - allows EMI optimization and inductor size reduction; externally synchronized in PWM mode only. |
| Quiescent Current in Shutdown | 1.2µA max - minimizes system standby power loss during deep sleep or fault conditions. |
| Operating Junction Temp | –40°C to +150°C - rated for harsh environments including motor drives and outdoor building controls. |
Pinout & Package
The MAX17551AUB+ is packaged in a 10-pin TDFN (3mm × 2mm) with exposed pad, optimized for thermal performance and PCB area efficiency. Pin assignments are validated per Maxim's official pin configuration diagram and electrical characteristics table.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IN | Input supply connection | Bypassed with 1µF X7R ceramic; withstands 70V absolute max; powers internal LDO and gate drivers. |
| EN/UVLO | Enable and input UVLO input | Active-high logic; 1.25V rising threshold; configurable via resistor divider to set turn-on voltage. |
| RT/SYNC | Oscillator timing & sync interface | Accepts resistor to GND for fSW programming (100kHz–2.2MHz) or AC-coupled external clock (PWM mode only). |
| SS | Soft-start control | Internal 5µA current source charges external cap; sets monotonic VOUT ramp time; discharged during shutdown. |
| FB | Output voltage feedback | Connects to resistor divider from VOUT; regulates to 0.8V reference with ±1.75% accuracy over temperature. |
| VOUT | External bias input | Connected to output rail via 22.1Ω + 0.22µF for 3.3V–5V outputs; tied to GND otherwise to avoid exceeding –0.3V rating. |
| RESET | Open-drain output monitor | Pulls low when FB drops below 92% of set value; high-impedance after 2ms delay when FB rises above 95%. |
| MODE | PFM/PWM selection | Unconnected = auto PFM at light load; grounded = forced PWM at all loads; not dynamically switchable. |
| GND | Power and signal ground | Single-point star ground connection required; EP (exposed pad) must be soldered to GND plane for thermal conduction. |
| LX | Switch node | Connects to inductor; high-impedance in shutdown; handles ±0.8A RMS current; requires low-inductance layout. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated high-side pMOS and low-side nMOS | Eliminates need for external Schottky diode and reduces BOM count; RDS(on) = 2.7Ω (HS) / 1.25Ω (LS) typical. |
| Programmable switching frequency | 100kHz–2.2MHz via single RT resistor; avoids sensitive EMI bands and enables optimal inductor selection. |
| Internal soft-start with monotonic startup | Prevents output voltage undershoot/overshoot into prebiased loads; eliminates need for external sequencing circuitry. |
| PFM mode with hibernate operation | Skips pulses at light loads; draws only 22µA IQ; exits hibernate automatically when load exceeds ~39mA – ΔI/2. |
| Comprehensive protection suite | Includes cycle-by-cycle peak current limit (110mA typ), negative current limit, thermal shutdown (160°C), and RESET-based output monitoring. |
Applications
| Industrial Sensor Power | High-Voltage LDO Replacement |
|---|---|
Use Scenario: Powering 4–20mA loop-powered temperature, pressure, or flow sensors in factory automation cabinets with 24V or 48V rails. IC Role / Device Role / Timing Role: Primary step-down regulator generating stable 3.3V or 5V from unregulated HV bus; delivers precise bias to ADCs, transceivers, and microcontrollers. Use Value: Replaces inefficient linear regulators, reducing heat generation by >85% and enabling sealed enclosures without heatsinks. | Use Scenario: Replacing discrete 60V-input LDOs in programmable logic controllers (PLCs) and distributed I/O modules requiring clean 3.3V/5V for digital logic. IC Role / Device Role / Timing Role: Efficient buck converter with built-in soft-start and RESET monitoring, replacing thermally limited linear solutions. Use Value: Cuts board power dissipation from >1W to <100mW at 50mA load, enabling higher channel density and extended MTBF. |
| HVAC Zone Controller | Battery-Powered Remote Monitor |
Use Scenario: Supplying 3.3V to wireless communication ICs (e.g., Zigbee, LoRa) and environmental sensors in rooftop HVAC units powered from 24VAC rectified rails. IC Role / Device Role / Timing Role: Input-tolerant DC-DC stage converting rectified 34V peak to regulated 3.3V; operates reliably across line dips and surges. Use Value: Maintains regulation down to 4V input, survives brownouts common in field-installed HVAC equipment. | Use Scenario: Long-life power for solar-charged IoT soil moisture or air quality sensors deployed in remote agricultural sites. IC Role / Device Role / Timing Role: Ultra-low-IQ buck converter enabling multi-year operation on 3.6V LiSOCl₂ cells; PFM mode extends runtime at microamp-level sensor sleep currents. Use Value: Achieves 22µA no-load IQ and 1.2µA shutdown, extending battery life beyond 10 years in duty-cycled applications. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down regulator applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX17552AUB+ | Same package and pinout; supports higher 100mA output current; identical 4V–60V input range and 22µA IQ. | Suitable where future-proofing for higher load or margin is required; same PCB layout but higher cost and thermal demand. | Select MAX17552AUB+ if output current headroom >50mA is needed; otherwise MAX17551AUB+ offers optimal cost/size/IQ trade-off. |
| LM5165QDGSRQ1 | Automotive-grade (AEC-Q100); 3V–65V input; 150mA output; 17µA IQ; requires external compensation and MOSFETs. | Designed for automotive under-hood use; lacks integrated FETs and internal compensation; needs more external components. | Choose LM5165QDGSRQ1 only for AEC-Q100 compliance requirements; MAX17551AUB+ provides simpler, smaller, lower-BOM solution for industrial use. |
Compared with MAX17552AUB+, the MAX17551AUB+ saves cost and board space for ≤50mA loads; compared with LM5165QDGSRQ1, it delivers faster design cycle, lower component count, and better light-load efficiency - but lacks automotive qualification.
Availability
The MAX17551AUB+ is available at Aetrix Electronics and suitable for industrial sensors and process control, HVAC and building control, and battery-powered equipment requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for MAX17551AUB+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated, now part of Analog Devices, designs precision analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.
The MAX17551AUB+ belongs to Maxim's ultra-small, high-voltage synchronous buck regulator family, engineered specifically for space- and power-constrained industrial sensing and control applications where input voltage range, quiescent current, and reliability outweigh raw output current capability.
FAQ
What is the maximum input voltage rating for the MAX17551AUB+?
The MAX17551AUB+ has an absolute maximum input voltage rating of 70V on the IN pin, with guaranteed continuous operation from 4V to 60V. This 60V upper limit ensures reliable performance in industrial 48V systems and battery-powered equipment with voltage spikes, while maintaining safety margins per JEDEC standards.
Does the MAX17551AUB+ require external compensation components?
No, the MAX17551AUB+ features internal compensation optimized for any output voltage setting between 0.8V and 0.9 × VIN. This eliminates external compensation networks, simplifies design, and guarantees stability across the full output range without requiring loop analysis or component tuning.
How does the MODE pin affect efficiency and noise performance in the MAX17551AUB+?
When the MODE pin is unconnected, the MAX17551AUB+ operates in PFM mode at light loads, achieving 22µA no-load IQ and higher efficiency below ~10mA. When grounded, it forces PWM mode - delivering fixed-frequency operation (reducing EMI variability) but increasing light-load IQ to ~180µA, making it preferable for noise-sensitive or frequency-synchronized systems.
Can the MAX17551AUB+ start up into a prebiased output voltage?
Yes, the MAX17551AUB+ supports monotonic startup into a prebiased output. During power-up, both high-side and low-side MOSFETs remain off until the first PWM pulse is commanded, preventing reverse current flow and ensuring controlled, overshoot-free voltage ramp-up - critical for systems with backup supplies or hot-swap configurations.
What is the function of the VOUT pin on the MAX17551AUB+ and how should it be connected?
The VOUT pin on the MAX17551AUB+ provides external bias for internal circuitry. For 3.3V–5V outputs, connect it to the output capacitor's positive terminal via a 22.1Ω resistor and 0.22µF capacitor to reduce input supply current and improve efficiency. For outputs <3.3V or >5V, tie VOUT directly to GND to prevent violation of its –0.3V absolute minimum rating.
MAX17551AUB+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- Himalaya
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 4V
- Voltage - Input (Max):
- 60V
- Voltage - Output (Min/Fixed):
- 0.8V
- Voltage - Output (Max):
- 54V
- Current - Output:
- 50mA
- Frequency - Switching:
- 100kHz ~ 2.2MHz
- Synchronous Rectifier:
- Yes
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-uMAX/uSOP
MAX17551AUB+ FAQ
1.How can I place an order for MAX17551AUB+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX17551AUB+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX17551AUB+ reliable?
The price and inventory of MAX17551AUB+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX17551AUB+ is usually 5 days.
3.What payment methods are accepted for MAX17551AUB+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX17551AUB+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX17551AUB+?
MAX17551AUB+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX17551AUB+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX17551AUB+?
For technical support, including MAX17551AUB+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX17551AUB+ requirements.
6.How does Aetrix verify that MAX17551AUB+ is sourced from the original manufacturer or authorized distributors?
All MAX17551AUB+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX17551AUB+ meets industry standards.
7.What is the process for return or replacement of MAX17551AUB+?
All MAX17551AUB+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX17551AUB+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX17551AUB+ part is unused and in its original packaging.
Return procedure for MAX17551AUB+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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