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Analog Devices Inc. LTC4290BIUJ#PBF
- Part No.:
- LTC4290BIUJ#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 40-WFQFN Exposed Pad
- Datasheet:
-
LTC4290BIUJ#PBF.pdf
- Description:
- IC POE CNTRL 8 CHANNEL 40QFN
- Quantity:
- Payment:
- Shipping:
Inventory:200
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Product details
Overview
LTC4290BIUJ#PBF from Analog Devices (formerly Linear Technology) is an 8-channel IEEE 802.3at Type 2 (PoE+) Power Sourcing Equipment (PSE) controller, designed for midspan and endpoint PSE systems delivering up to 25.5W per port. It operates with a –45V to –57V VEE supply, integrates per-port 12-bit current monitoring ADCs, supports transformer-isolated communication, and uses 0.25Ω sense resistors for precise current limiting in PoE+ infrastructure.
For engineers reviewing the LTC4290BIUJ#PBF datasheet, LTC4290BIUJ#PBF pinout, LTC4290BIUJ#PBF application, or LTC4290BIUJ#PBF equivalent, key selection considerations include its B-grade 25.5W power delivery capability, I²C interface up to 1MHz, dual-mode 4-point PD detection, 2-event classification for midspan mode, and compatibility with external low-RDS(ON) MOSFETs in 40-lead 6mm × 6mm QFN packaging.
Technical Context
The LTC4290BIUJ#PBF functions as the analog front-end of a two-chip PSE chipset, paired exclusively with the LTC4271 host controller. It handles high-voltage port control, current sensing, gate driving, and isolation-critical analog signaling - including transformer-coupled clock/data transceivers (CPA/CNA/DPD/DND) - eliminating optocouplers and isolated 3.3V supplies.
It implements IEEE 802.3at Type 2 compliant detection (forced voltage + forced current), classification (2-event), and power application with programmable current limits (VLIM = 204–225 mV), overcurrent protection (VCUT = 152–168 mV), and DC disconnect (VMIN = 1.3–2.45 mV), all referenced to VEE and operating across –40°C to +85°C ambient.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| IEEE Compliance | 802.3at Type 2 (PoE+), fully supports 25.5W per port with 2-event classification and midspan backoff timer |
| Max Delivered Power | 25.5W per port (B-grade specification; not LTPoE++ or PoE) |
| Sense Resistor | 0.25Ω per channel - enables accurate current monitoring and low-power dissipation with external MOSFETs |
| Current Limit Threshold | 204–225 mV (high-power mode), corresponding to ~816–900 mA at 0.25Ω for precise ILIM enforcement |
| I²C Interface Speed | Up to 1 MHz - allows fast register access and real-time port status polling without bus contention |
| Operating Temperature | –40°C to +85°C ambient - qualified for industrial and telecom infrastructure environments |
| Package | 40-lead 6mm × 6mm plastic QFN with exposed VSSK pad - optimized for thermal management in high-current PSE designs |
Pinout & Package
The LTC4290BIUJ#PBF is housed in a 40-lead (6mm × 6mm) plastic QFN package with exposed VSSK pad (Pin 41) requiring PCB soldering for Kelvin VEE sensing. Pin functions are strictly segregated: eight GATE/OUT/SENSE triplets for independent port control, transformer-coupled analog I/O (CPA/CNA/DPD/DND), and high-side digital I/O (XIO0/XIO1) referenced to VEE.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VEE (Pins 1, 30, 33, 40) | Main PoE supply input | Accepts –45V to –57V relative to AGND; powers all analog circuitry and gate drivers |
| GATEn (Pins 2, 4, 7, 9, 22, 24, 27, 29) | Port n MOSFET gate driver output | Drives external high-side N-channel MOSFET gate to ~12V above VEE; includes fast pull-down for fault shutdown |
| OUTn (Pins 3, 5, 8, 10, 21, 23, 26, 28) | Port n output voltage monitor | Reports port voltage via internal 500kΩ pull-down to AGND when idle; triggers PG bit at <2.4V (VEE-referenced) |
| SENSEn (Pins 12–19) | Port n current sense input | Measures voltage across 0.25Ω sense resistor to VEE; enables 12-bit ADC readback and VLIM/VCUT fault detection |
| CPA/CNA/DPD/DND (Pins 37, 38, 10, 11) | Transformer-isolated clock/data transceivers | Eliminates need for optocouplers; supports galvanic isolation between LTC4290 and LTC4271 without external isolators |
| VSSK (Pin 41, Exposed Pad) | Kelvin sense return for VEE | Must connect to sense resistor common node - not to main VEE plane - to reject PCB trace resistance errors |
Key Features
| Feature | Design Value |
|---|---|
| Dual-mode 4-point PD detection | Combines forced voltage and forced current detection to prevent false PD identification in noisy environments |
| Transformer-isolated communication | Replaces 6+ optocouplers and isolated 3.3V supply - reduces BOM cost and layout complexity |
| Per-port 12-bit current monitoring | Enables real-time power budgeting and diagnostics with 30.5 µV/LSB resolution on VSENSE–VEE |
| DAC-programmable current limit | Allows dynamic adjustment of VLIM threshold via LTC4271 registers to support varying PD load profiles |
| Fast masked shutdown (MSD) | Hardware-controlled port reset with <7µs latency - critical for rapid fault containment in multi-port systems |
| Midspan mode support | Configurable via LTC4271 MID pin to enable 2-second backoff timer and 2-event classification for legacy midspan deployment |
Applications
| IP Phone Power Management | Wireless Access Point PSE |
|---|---|
Use Scenario: Enterprise VoIP phone deployment requiring reliable, standards-compliant power with hot-swap capability and remote diagnostics. IC Role / Device Role: LTC4290BIUJ#PBF serves as the high-voltage analog controller in an 8-port PSE switch, managing detection, classification, and current-limited power application per port. Use Value: Enables full IEEE 802.3at compliance with 25.5W headroom for advanced phones with color displays and Bluetooth modules, while reducing thermal stress via low-RDS(ON) MOSFET drive. |
Use Scenario: High-density Wi-Fi 6/6E access point installation in office ceilings, where PoE+ power must be delivered reliably across long cable runs with EMI resilience. IC Role / Device Role: LTC4290BIUJ#PBF provides per-port voltage/current monitoring and fast foldback response to handle AP inrush currents and maintain stable 25.5W delivery under load transients. Use Value: Its 12-bit current ADC and 25ms conversion period allow real-time power budgeting and predictive maintenance alerts before thermal derating occurs. |
| Security Camera Midspan Injector | Industrial IoT Gateway PSE |
Use Scenario: Retrofitting legacy non-PoE network switches with midspan PoE+ injectors powering PTZ cameras with heaters and IR illuminators. IC Role / Device Role: LTC4290BIUJ#PBF operates in midspan mode (MID = HIGH) with 2-event classification and 2.5s backoff timer to ensure interoperability with diverse camera PDs. Use Value: Eliminates need for isolated 3.3V supplies and optocouplers - simplifying UL/IEC62368-1 certification and reducing bill-of-materials by >$0.40/unit. |
Use Scenario: Factory-floor edge gateway aggregating sensor data from multiple PoE-powered devices, requiring robust fault handling and deterministic port control. IC Role / Device Role: LTC4290BIUJ#PBF executes hardware-based fast shutdown (MSD) and maintains MPS timing (tDIS = 350ms) to sustain power during brownouts per IEEE 802.3bt requirements. Use Value: Its VEE-referenced XIO0/XIO1 pins enable direct connection to isolated microcontrollers for autonomous port sequencing without level-shifting components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar PoE+ PSE controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| Microchip LAN9303-ABZ | Integrated 3-port Ethernet switch + PoE+ PSE in single chip; no external MOSFET required but fixed 25.5W max per port | Targeted at compact embedded PSEs; lacks transformer-isolation capability and per-port ADC resolution | Select when board space is constrained and discrete MOSFET flexibility is unnecessary |
| Maxim MAX5984AEUI+ | Single-chip 4-port PoE+ PSE with integrated MOSFET drivers and 10-bit ADC; no transformer isolation - requires optocouplers for host isolation | Designed for cost-sensitive endpoint switches; does not support midspan mode or LTPoE++ grading | Select for simpler 4-port designs where isolation is handled externally and BOM count is prioritized over diagnostic fidelity |
Compared with LAN9303-ABZ and MAX5984AEUI+, the LTC4290BIUJ#PBF delivers superior thermal efficiency via external MOSFET optimization, higher-resolution current monitoring (12-bit vs 10-bit), and native transformer isolation - making it optimal for high-reliability, field-upgradeable 8-port midspan and enterprise switch PSEs.
Availability
LTC4290BIUJ#PBF is available at Aetrix Electronics and suitable for PoE+ midspan injectors, enterprise Ethernet switches, and industrial IoT gateways requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant manufacturing.
Supply support for LTC4290BIUJ#PBF 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
Analog Devices acquired Linear Technology in 2017 and maintains its high-performance analog portfolio, specializing in precision power, signal conditioning, and interface ICs for industrial, communications, and automotive markets.
The LTC4290BIUJ#PBF belongs to the LTC4290/LTC4271 chipset family, engineered specifically for scalable, transformer-isolated PoE+ PSE systems - emphasizing thermal efficiency, noise-immune PD detection, and seamless integration with host microcontrollers via I²C.
FAQ
What is the maximum power delivery capability of the LTC4290BIUJ#PBF?
The LTC4290BIUJ#PBF is the B-grade variant of the LTC4290/LTC4271 chipset and is rated for IEEE 802.3at Type 2 (PoE+) compliance, delivering up to 25.5W per port. This is confirmed in the Order Information table and Electrical Characteristics section, where B-grade operation is explicitly tied to 25.5W maximum delivered power - distinct from A-grade (90W LTPoE++) and C-grade (13W PoE) variants.
Does the LTC4290BIUJ#PBF require an external host controller?
Yes, the LTC4290BIUJ#PBF must be used with the LTC4271 host controller. It is not a standalone device: the LTC4290 handles high-voltage analog functions (gate driving, current sensing, isolation), while the LTC4271 provides digital control, I²C interface, register management, and system-level logic. The datasheet explicitly defines them as a "chipset" with interdependent functionality and no autonomous operation mode for LTC4290BIUJ#PBF.
How does the LTC4290BIUJ#PBF achieve transformer isolation without optocouplers?
The LTC4290BIUJ#PBF achieves transformer isolation using dedicated analog transceiver pins - CPA/CNA (clock) and DPD/DND (data) - which connect directly to external data transformers. These pins operate differentially and tolerate ±10V common-mode swing, enabling galvanic isolation between the high-voltage LTC4290BIUJ#PBF and low-voltage LTC4271 without optocouplers or isolated DC/DC converters, as verified in the Applications section and PIN FUNCTIONS description.
What is the role of the VSSK pin on the LTC4290BIUJ#PBF?
The VSSK pin (exposed pad, Pin 41) is the Kelvin sense return for the VEE supply and must be connected to the common node of the 0.25Ω sense resistors - not to the main VEE power plane. This configuration eliminates voltage drop errors caused by PCB trace resistance, ensuring accurate current measurement and stable current limiting. The datasheet mandates this connection in both the Absolute Maximum Ratings and PIN FUNCTIONS sections.
Can the LTC4290BIUJ#PBF operate in midspan mode?
Yes, the LTC4290BIUJ#PBF supports midspan mode when used with the LTC4271 configured via the MID pin. In this mode, it implements 2-event classification and a 2.5-second backoff timer, as specified in the FEATURES and ELECTRICAL CHARACTERISTICS tables. Midspan operation is validated in the Typical Application diagram and explicitly called out in the ORDER INFORMATION table for all LTC4290 grades, including the B-grade LTC4290BIUJ#PBF.
LTC4290BIUJ#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 40-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Controller (PSE)
- Number of Channels:
- 8
- Power - Max:
- 25.5 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE)
- Voltage - Supply:
- 3V ~ 3.6V
- Current - Supply:
- 10mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 40-QFN (6x6)
LTC4290BIUJ#PBF FAQ
1.How can I place an order for LTC4290BIUJ#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4290BIUJ#PBF 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 LTC4290BIUJ#PBF reliable?
The price and inventory of LTC4290BIUJ#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4290BIUJ#PBF is usually 5 days.
3.What payment methods are accepted for LTC4290BIUJ#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4290BIUJ#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4290BIUJ#PBF?
LTC4290BIUJ#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4290BIUJ#PBF 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 LTC4290BIUJ#PBF?
For technical support, including LTC4290BIUJ#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4290BIUJ#PBF requirements.
6.How does Aetrix verify that LTC4290BIUJ#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4290BIUJ#PBF 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 LTC4290BIUJ#PBF meets industry standards.
7.What is the process for return or replacement of LTC4290BIUJ#PBF?
All LTC4290BIUJ#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4290BIUJ#PBF, 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 LTC4290BIUJ#PBF part is unused and in its original packaging.
Return procedure for LTC4290BIUJ#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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