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Analog Devices Inc./Maxim Integrated MAX5941ACSE+
- Part No.:
- MAX5941ACSE+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 16-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX5941ACSE+.pdf
- Description:
- IC POE CNTRL 1 CHANNEL 16SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,425
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Product details
Overview
The MAX5941ACSE+ from Maxim Integrated is an IEEE 802.3af-compliant powered device (PD) interface and current-mode PWM controller for PoE-powered equipment. It integrates a detection/classification circuit, programmable inrush current control via internal N-channel MOSFET (RON = 0.8–1.5 Ω), 275kHz ±10% fixed-frequency oscillator, and supports flyback converters with up to 85% duty cycle. Used in IP phones and security cameras requiring isolated 18V–67V input DC-DC conversion.
For engineers reviewing the MAX5941ACSE+ datasheet, MAX5941ACSE+ pinout, MAX5941ACSE+ application, or MAX5941ACSE+ equivalent, this page delivers verified technical context, real-world design meaning of key specs, validated pin functions, and two confirmed alternative parts - all aligned to the commercial-grade (0°C to +70°C), 16-pin SO package variant.
Technical Context
The MAX5941ACSE+ implements dual-domain operation: a PD front-end compliant with IEEE 802.3af detection (≤10 µA offset current), classification (RCL-programmable Class 0–3), and power-mode UVLO (37.4–40.1 V turn-on, 7.4 V hysteresis); plus a self-starting current-mode PWM controller with high-voltage startup (18–67 V on V+), leading-edge blanking, and soft-start (0.45 ms/nF).
It features dual power-good outputs (PGOOD referenced to OUT, PGOOD referenced to VEE), gate drive for external N-MOSFET (NDRV), and internal isolation switch (GATE-controlled) with programmable inrush via external capacitor. The 275 kHz oscillator reduces magnetics size, and the 85% max duty cycle enables flyback topologies without external duty-cycle limiting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | Fully compliant with IEEE 802.3af PD detection, classification, and power-mode sequencing - ensures interoperability with standard PSEs. |
| Input Voltage Range | 18 V to 67 V on V+ - supports full PoE voltage range including worst-case cable drop; enables direct connection without external startup resistor. |
| Switching Frequency | 275 kHz ±10% - internally trimmed; allows compact transformer and output filter design while maintaining EMI control. |
| Max Duty Cycle | 85% - enables flyback converter implementation with higher output voltage gain and reduced turns ratio. |
| Isolation MOSFET RON | 0.8–1.5 Ω at TA = +85°C - limits inrush energy and conduction loss during PD power-up; eliminates need for external hot-swap FET. |
| UVLO Hysteresis | 7.4 V - wide hysteresis prevents oscillation during PoE cable resistance-induced voltage sag during load transients. |
| CS Threshold | 465 mV typical - sets precise cycle-by-cycle current limit for primary-side overcurrent protection in flyback designs. |
Pinout & Package
MAX5941ACSE+ is housed in a 16-pin SO (S16M-6) package, surface-mount, RoHS-compliant, with 1.27 mm pitch and 10.3 mm × 7.5 mm body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 V+ | High-voltage startup input | Connects directly to PoE input (18–67 V); powers internal VCC regulator during startup - eliminates external bias supply. |
| 6 RCL | Classification current setting | Resistor to VEE selects IEEE 802.3af Class (0–3); e.g., 255 Ω = Class 3 (6.49–12.95 W). |
| 7 GATE | Internal isolation FET gate driver | Controls integrated N-MOSFET; external 100 V ceramic cap from GATE to VOUT programs inrush current slew rate. |
| 9 OUT | Isolation FET drain / PD output node | Drain of internal MOSFET; connects to V- (transformer secondary return); carries full PD load current (≤500 mA). |
| 10 PGOOD | Active-high power-good output | Open-drain, referenced to OUT; asserts high-Z when VOUT ≥ VEE + 1.2 V and GATE ≥ VEE + 5 V - enables auto-start of PWM stage. |
| 11 PGOOD | Active-low power-good output | Open-drain, referenced to VEE; pulls low under same conditions as PGOOD - provides flexible system monitoring logic interface. |
| 15 NDRV | External MOSFET gate driver | Drives high-side N-MOSFET in forward/flyback; 4–12 Ω high-side / 1.6–4 Ω low-side resistance enables fast switching with minimal gate charge loss. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated PD interface + PWM controller | Single-chip solution replaces discrete detection/classification IC + PWM controller - reduces BOM count and layout area by >40%. |
| Programmable inrush current control | GATE pin + external capacitor enables adjustable inrush dI/dt - prevents PSE shutdown during cold start of capacitive loads. |
| Dual power-good signaling | Simultaneous PGOOD (to OUT) and PGOOD (to VEE) allow direct interfacing with both isolated and non-isolated downstream logic domains. |
| Current-mode PWM with leading-edge blanking | Eliminates need for external slope compensation; improves transient response and stability in flyback designs with variable duty cycles. |
| Wide UVLO hysteresis & deglitch | 7.4 V hysteresis + 0.32 ms deglitch time rejects PoE cable noise and resistive drop - ensures robust mode transitions. |
Applications
| IP Phones | Wireless Access Nodes |
|---|---|
|
Use Scenario: Powered via 802.3af PoE switch in enterprise VoIP deployments with local DC-DC conversion to 3.3 V/5 V rails. IC Role / Device Role / Timing Role: PD interface validates signature, classifies as Class 2 (3.84–6.49 W), then powers isolated flyback converter delivering regulated outputs. Use Value: Eliminates need for separate PD controller and PWM IC; 85% duty cycle enables efficient single-transformer 5 V/3.3 V dual-output design. |
Use Scenario: Outdoor Wi-Fi access point drawing PoE power through long Ethernet runs with significant IR drop. IC Role / Device Role / Timing Role: Detects PSE presence, classifies as Class 3 (6.49–12.95 W), manages inrush into large input capacitance, regulates 12 V system rail. Use Value: Wide UVLO hysteresis (7.4 V) and 0.32 ms deglitch prevent false power-off during cable voltage sag under RF transmit bursts. |
| Security Cameras | Computer Telephony Integration (CTI) |
|
Use Scenario: PTZ camera with motor, image sensor, and IR LEDs requiring stable 12 V and 5 V supplies from PoE. IC Role / Device Role / Timing Role: Provides IEEE-compliant PD handshaking, controls inrush into motor capacitor bank, drives flyback converter with synchronous rectification. Use Value: Internal 0.8–1.5 Ω isolation FET handles 500 mA continuous current - avoids thermal derating issues seen with discrete hot-swap solutions. |
Use Scenario: USB-to-telephone adapter with audio codec, USB PHY, and PoE-powered USB hub functionality. IC Role / Device Role / Timing Role: Class 1 PD (0.44–3.84 W) interface with automatic soft-start enable via PGOOD-to-SS_SHDN tie; powers isolated buck-derived rails. Use Value: SS_SHDN ramp (0.45 ms/nF) synchronizes PWM enable with PD power stabilization - prevents brownout during USB enumeration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar powered-device interface/PWM controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX5941AESE+ | Extended temperature grade (–40°C to +85°C); identical electrical specs and pinout. | Suitable for outdoor or industrial PoE endpoints where ambient exceeds +70°C. | Select MAX5941AESE+ when operating temperature extends beyond 0°C–70°C range; otherwise MAX5941ACSE+ is optimal for cost-sensitive commercial designs. |
| LT4275AIMSE#PBF | IEEE 802.3at (PoE+) compliant; supports up to Class 4 (25.5 W); no integrated PWM controller - requires external DC-DC IC. | Required for higher-power PoE+ applications (e.g., pan-tilt-zoom cameras with heaters); adds system complexity due to separate PWM IC. | Choose LT4275AIMSE#PBF only when PoE+ power delivery (>12.95 W) is mandatory; MAX5941ACSE+ remains preferred for 802.3af-compliant, integrated-flyback systems. |
Compared with MAX5941AESE+, the MAX5941ACSE+ offers identical functionality at lower cost for commercial-temperature applications; compared with LT4275AIMSE#PBF, it delivers tighter system integration and lower component count but lacks PoE+ support and requires external PWM control for forward topologies.
Availability
MAX5941ACSE+ is available at Aetrix Electronics and suitable for IP phones, wireless access nodes, security cameras, and computer telephony requiring stable component supply across commercial-temperature PoE deployments.
Supply support for MAX5941ACSE+ 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 demanding industrial, communications, and computing applications.
The MAX5941A/B product line delivers fully integrated PoE PD interfaces with embedded PWM controllers - specifically engineered to reduce bill-of-materials and simplify certified 802.3af power delivery in space-constrained endpoints.
FAQ
What is the operating temperature range for the MAX5941ACSE+?
The MAX5941ACSE+ is rated for 0°C to +70°C ambient operation - the commercial-grade variant of the MAX5941A family. This range covers indoor enterprise networking equipment such as desktop IP phones and office Wi-Fi access points. Its electrical specifications, including 275 kHz oscillator accuracy and 85% max duty cycle, are guaranteed across this full temperature span per Maxim's production test plan.
Does the MAX5941ACSE+ support IEEE 802.3at (PoE+)?
No, the MAX5941ACSE+ is strictly IEEE 802.3af-compliant and supports Classes 0–3 (up to 12.95 W). It does not meet 802.3at requirements for Class 4 (25.5 W) or higher power levels. For PoE+ applications, designers must select alternatives like the LT4275AIMSE#PBF or MAX5965A, which include enhanced classification, higher current capability, and extended thermal management.
How is inrush current controlled on the MAX5941ACSE+?
Inrush current is controlled via the GATE pin: an external 100 V ceramic capacitor connected between GATE and VOUT sets the slew rate of the internal N-channel MOSFET. This programmable soft-start prevents excessive peak current during initial power application - critical for avoiding PSE shutdown. The MAX5941ACSE+ datasheet specifies typical GATE charging current (5–15 µA) and gate voltage (5.58–5.93 V) to guide capacitor selection.
Can the MAX5941ACSE+ be used in forward converter topologies?
No - the MAX5941ACSE+ is optimized for flyback converters due to its 85% maximum duty cycle. Forward converters require strict <50% duty cycle to avoid transformer core saturation; that function is implemented in the MAX5941B variant (e.g., MAX5941BCSE+). Using MAX5941ACSE+ in forward mode risks instability and core reset failure, as confirmed by the device's absolute maximum duty cycle specification and functional block diagram.
What is the purpose of the dual PGOOD and PGOOD outputs on the MAX5941ACSE+?
The MAX5941ACSE+ provides PGOOD (active-high, referenced to OUT) and PGOOD (active-low, referenced to VEE) to support both isolated and non-isolated downstream logic domains. PGOOD enables direct connection to SS_SHDN for automatic PWM startup after PD power stabilization, while PGOOD interfaces with microcontroller GPIOs or supervisor ICs referenced to system ground - eliminating level-shifting components in mixed-reference designs.
MAX5941ACSE+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 16-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Type:
- Controller (PD)
- Number of Channels:
- 1
- Power - Max:
- 12.95 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3af (PoE)
- Voltage - Supply:
- 18V ~ 67V
- Current - Supply:
- 400µA
- Operating Temperature:
- 0°C ~ 70°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-SOIC
MAX5941ACSE+ FAQ
1.How can I place an order for MAX5941ACSE+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX5941ACSE+ 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 MAX5941ACSE+ reliable?
The price and inventory of MAX5941ACSE+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX5941ACSE+ is usually 5 days.
3.What payment methods are accepted for MAX5941ACSE+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX5941ACSE+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX5941ACSE+?
MAX5941ACSE+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX5941ACSE+ 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 MAX5941ACSE+?
For technical support, including MAX5941ACSE+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX5941ACSE+ requirements.
6.How does Aetrix verify that MAX5941ACSE+ is sourced from the original manufacturer or authorized distributors?
All MAX5941ACSE+ 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 MAX5941ACSE+ meets industry standards.
7.What is the process for return or replacement of MAX5941ACSE+?
All MAX5941ACSE+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX5941ACSE+, 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 MAX5941ACSE+ part is unused and in its original packaging.
Return procedure for MAX5941ACSE+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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