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Analog Devices Inc./Maxim Integrated MAX5953BUTM+
- Part No.:
- MAX5953BUTM+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 48-WFQFN Exposed Pad
- Datasheet:
-
MAX5953BUTM+.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 48TQFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,594
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Product details
Overview
The MAX5953BUTM+ from Maxim Integrated is an IEEE 802.3af-compliant Powered Device (PD) interface and voltage-mode PWM controller IC with integrated high-voltage power MOSFETs, designed for PoE-powered endpoints. It delivers up to 15W output power, features a fixed 35.4V UVLO turn-on threshold, supports forward/flyback DC-DC topologies, and integrates isolation switching with <10µA detection leakage current - enabling robust operation in IP phones and security cameras.
For engineers reviewing the MAX5953BUTM+ datasheet, MAX5953BUTM+ pinout, MAX5953BUTM+ application, or MAX5953BUTM+ equivalent, this page provides verified technical context, confirmed pin functions, real-world use cases in PoE infrastructure, and validated alternative parts for legacy PSE compatibility and thermal design trade-offs.
Technical Context
The MAX5953BUTM+ implements a two-switch, voltage-clamped DC-DC converter architecture with integrated 0.4Ω high-side and low-side MOSFETs, operating across 11V–76V input range. Its feed-forward voltage-mode control enables fast input transient rejection, while the look-ahead PPWM signal synchronizes secondary-side rectifiers to achieve >90% efficiency.
Its PD interface includes programmable classification (Class 0–4), detection signature compliance, and a dedicated isolation MOSFET with 0.6Ω on-resistance. The fixed UVLO threshold (34.3V–36.9V) ensures compatibility with pre-802.3af PSEs, and undervoltage lockout features wide hysteresis (4V) and 0.32ms deglitch time to suppress cable-drop-induced false transitions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Standard Compliance | Fully compliant with IEEE 802.3af for Powered Device detection, classification, and power delivery - no external signature components required. |
| UVLO Turn-On Threshold | Fixed 35.4V (min/max 34.3V/36.9V); enables reliable startup with legacy PSEs lacking full 802.3af support. |
| Max Output Power | 15W; sufficient for mid-power PoE endpoints including wireless access nodes and HD security cameras. |
| Input Voltage Range | 11V to 76V DC; accommodates PoE voltage drop across long Ethernet cables and supports 802.3at-compatible designs with margin. |
| Switching Frequency | Up to 500kHz; allows compact magnetics and reduces EMI filter size without sacrificing regulation stability. |
| Detection Leakage Offset | <10µA; guarantees reliable PD detection under worst-case temperature and process variation per 802.3af Clause 14.2.1. |
| Integrated MOSFET RDS(ON) | 0.4Ω (high-side/low-side); eliminates external switch cost and layout complexity while supporting 15W at high efficiency. |
Pinout & Package
MAX5953BUTM+ uses a thermally enhanced 48-pin TQFN package (7mm × 7mm, pkg code T4877-6), with exposed paddle connected to VEE for improved heat dissipation (θJA = 36°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 4, V+ | Positive PD input rail | Accepts PoE input up to +90V; referenced to VEE; connects to Ethernet transformer center tap. |
| 10–11, VEE | Negative PD input rail / MOSFET source | Return path for PD interface; internal isolation MOSFET source node; exposed paddle must be soldered to VEE plane. |
| 15–16, OUT | Isolated PD output node | Drain of internal isolation MOSFET; supplies downstream DC-DC stage; must connect to system GND. |
| 9, GATE | Isolation MOSFET gate driver | Programmable inrush control via external capacitor; drives internal n-channel switch; pulled to VEE to disable isolation. |
| 39, HVIN | DC-DC primary-side input | Connects directly to V+; powers internal PWM controller and gate drivers; rated for 11V–76V operation. |
| 41, REGOUT | Internal LDO output | 8.75V ±0.25V regulated supply for gate drivers and logic; bypassed with ≥2.2µF ceramic capacitor to GND. |
| 21, PPWM | Look-ahead PWM pulse output | Leads internal FET switching by ~100ns; used to drive synchronous rectifiers on secondary side for efficiency boost. |
| 37, DCUVLO | DC-DC UVLO sense input | Configurable via resistor divider from HVIN to GND; triggers shutdown if input drops below 1.26V reference. |
Key Features
| Feature | Design Value |
|---|---|
| Two-switch voltage-clamped topology | Recovers magnetizing and leakage energy to improve efficiency and reduce stress on MOSFETs vs. conventional flyback. |
| Programmable inrush current control | External capacitor on GATE pin sets soft-start slew rate, limiting inrush surge during power-up to protect upstream PSE. |
| Indefinite short-circuit protection with hiccup mode | FLTINT pin integrates fault current; disables switching at 2.7V and resumes at 1.9V, preventing thermal runaway under sustained overload. |
| Integrated bias regulator (REGOUT) | Delivers stable 8.75V/30mA supply independent of HVIN fluctuations - eliminates need for external bias winding or LDO. |
| Wide UVLO hysteresis & deglitch timing | 4V hysteresis and 0.32ms deglitch window prevent false power-down due to twisted-pair IR drop or noise transients. |
Applications
| IP Phones | Wireless Access Nodes |
|---|---|
|
Use Scenario: Powering VoIP handsets over Category 5e cabling with centralized PoE switches. IC Role / Device Role / Timing Role: PD interface + primary-side DC-DC controller managing 12V/1A local supply from 48V PoE input. Use Value: Eliminates external detection/classification circuitry and discrete MOSFETs, reducing BOM count by ≥7 components. |
Use Scenario: Deploying dual-band 802.11ac access points in ceiling-mounted enclosures with limited airflow. IC Role / Device Role / Timing Role: High-efficiency 15W PoE power conversion with thermal shutdown at +160°C to sustain operation in confined spaces. Use Value: 90%+ efficiency with synchronous rectification lowers thermal load, enabling fanless design and extended MTBF. |
| Security Cameras | Computer Telephony |
|
Use Scenario: Outdoor PTZ cameras requiring PoE+ power and robust surge immunity. IC Role / Device Role / Timing Role: Isolation switch + clamped DC-DC stage delivering clean 12V/1.25A to image sensor and motor drivers. Use Value: Integrated 0.4Ω MOSFETs and 76V absolute max rating withstand induced surges on long outdoor cable runs. |
Use Scenario: USB-C desktop telephony adapters drawing power and data over single Ethernet cable. IC Role / Device Role / Timing Role: Compact PD solution providing regulated 5V/2A output via buck configuration using high-side MOSFET. Use Value: 48-TQFN footprint (49 mm²) fits tight PCB areas; PPWM signal enables precise timing sync with secondary-side GaN FETs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar Powered Device interface and DC-DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX5953AUTM+ | Adjustable UVLO (12V–67V) via external resistor divider; default 38.6V turn-on matches 802.3af spec. | Better suited for new 802.3af deployments requiring standard-compliant startup; lacks legacy PSE compatibility. | Select MAX5953AUTM+ when designing for certified PSEs and needing field-programmable UVLO thresholds. |
| LT4275AIMSE#PBF | IEEE 802.3at/af-compliant PD interface only (no integrated DC-DC controller or MOSFETs); requires external flyback controller. | Used where higher power (>30W) or design flexibility justifies added component count and layout complexity. | Choose LT4275AIMSE#PBF when scaling beyond 15W or requiring multi-topology support (e.g., active clamp forward). |
Compared with MAX5953AUTM+, the MAX5953BUTM+ trades UVLO programmability for guaranteed legacy PSE interoperability; versus LT4275AIMSE#PBF, it delivers full integration at 15W but sacrifices scalability beyond PoE Type 1 limits.
Availability
MAX5953BUTM+ is available at Aetrix Electronics and suitable for IP phones, wireless access nodes, security cameras, and computer telephony systems requiring stable component supply, long-term lifecycle support, and consistent electrical performance across temperature extremes.
Supply support for MAX5953BUTM+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and computing markets.
The MAX5953 family targets IEEE 802.3af PoE endpoint design, integrating detection, classification, isolation, and DC-DC conversion to minimize external components and accelerate time-to-market for powered Ethernet devices.
FAQ
What is the UVLO threshold for MAX5953BUTM+ and why is it fixed?
The MAX5953BUTM+ has a fixed UVLO turn-on threshold of 35.4V (range 34.3V–36.9V) and turn-off at 30V, optimized for compatibility with pre-802.3af power-sourcing equipment. This fixed setting eliminates external resistor-divider tuning and ensures predictable startup behavior in legacy PoE infrastructure where adjustable thresholds could cause misalignment with PSE detection windows. The MAX5953BUTM+ maintains this behavior across its full operating temperature range.
Does MAX5953BUTM+ support both forward and flyback DC-DC configurations?
Yes, the MAX5953BUTM+ supports both forward and flyback topologies through its two-switch voltage-clamped architecture. When configured with the high-side MOSFET active, it operates as a forward converter; with the low-side MOSFET active, it functions as a flyback. The internal gate drivers, PPWM look-ahead signal, and integrated 0.4Ω MOSFETs are designed to work seamlessly in either mode without external reconfiguration.
How does MAX5953BUTM+ handle inrush current limiting during power-up?
The MAX5953BUTM+ implements programmable inrush current limiting via the GATE pin: connecting a ceramic capacitor between GATE and OUT sets the slew rate of the internal isolation MOSFET's turn-on, thereby controlling peak inrush. This avoids tripping upstream PSE current limits and prevents voltage droop that could disrupt detection/classification phases. No external current-sense resistors or control loops are required.
What is the role of the PPWM pin on MAX5953BUTM+ and how is it used?
The PPWM pin on MAX5953BUTM+ outputs a look-ahead pulse that leads the internal power MOSFET switching edge by ~100ns. It is referenced to GND and drives secondary-side synchronous rectifiers to minimize conduction loss and boost efficiency above 90%. This signal eliminates timing uncertainty in discrete gate-drive solutions and enables precise dead-time control without external delay circuits.
Can MAX5953BUTM+ be used in Class 4 PoE applications?
Yes, the MAX5953BUTM+ supports IEEE 802.3af Class 4 operation with a classification current of 36.6–41.4mA (at VIN = 12.6V–20V), set by an external resistor from RCLASS to VEE. Its integrated isolation MOSFET and detection circuitry meet all Class 4 signature requirements, and its 15W output capability aligns with the maximum power budget defined for Class 4 under 802.3af.
MAX5953BUTM+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 48-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Controller (PD), DC/DC
- Number of Channels:
- 1
- Power - Max:
- 15 W
- Internal Switch(s):
- Yes
- Auxiliary Sense:
- No
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 11V ~ 76V
- Current - Supply:
- 400µA
- Operating Temperature:
- 0°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 48-TQFN (7x7)
MAX5953BUTM+ FAQ
1.How can I place an order for MAX5953BUTM+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX5953BUTM+ 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 MAX5953BUTM+ reliable?
The price and inventory of MAX5953BUTM+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX5953BUTM+ is usually 5 days.
3.What payment methods are accepted for MAX5953BUTM+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX5953BUTM+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX5953BUTM+?
MAX5953BUTM+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX5953BUTM+ 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 MAX5953BUTM+?
For technical support, including MAX5953BUTM+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX5953BUTM+ requirements.
6.How does Aetrix verify that MAX5953BUTM+ is sourced from the original manufacturer or authorized distributors?
All MAX5953BUTM+ 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 MAX5953BUTM+ meets industry standards.
7.What is the process for return or replacement of MAX5953BUTM+?
All MAX5953BUTM+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX5953BUTM+, 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 MAX5953BUTM+ part is unused and in its original packaging.
Return procedure for MAX5953BUTM+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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