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Analog Devices Inc. LTC4270AIUKG#PBF
- Part No.:
- LTC4270AIUKG#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Power Over Ethernet (PoE) Controllers
- Package:
- 52-WFQFN Exposed Pad
- Datasheet:
-
LTC4270AIUKG#PBF.pdf
- Description:
- IC POE CNTRL 12 CHANNEL 52QFN
- Quantity:
- Payment:
- Shipping:
Inventory:205
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Product details
Overview
LTC4270AIUKG#PBF from Analog Devices is a 12-port IEEE 802.3at Type 1/Type 2 and LTPoE++ compliant Power Sourcing Equipment (PSE) controller for midspan and endpoint PoE systems. It delivers up to 90W per port using transformer-isolated communication, supports per-port 12-bit current monitoring, and integrates DAC-programmable current limit with fast shutdown. It is deployed in enterprise switches, PoE midspans, and high-power IP surveillance infrastructure.
For engineers reviewing the LTC4270AIUKG#PBF datasheet, LTC4270AIUKG#PBF pinout, LTC4270AIUKG#PBF application, or LTC4270AIUKG#PBF equivalent, key selection considerations include its A-grade 90W power delivery capability, transformer-based isolation eliminating optocouplers, 0.25Ω sense resistor support, 1MHz I²C interface, and dual-mode 4-point PD detection immunity to false classification.
Technical Context
The LTC4270AIUKG#PBF operates as the high-voltage analog front-end of a two-chip PSE solution, paired with the LTC4271 host controller. It handles all port-level analog functions: forced-voltage/forced-current detection, 2-event classification, VEE/VEE+54V supply management, gate drive for external N-channel MOSFETs, and precision current sensing via 0.25Ω resistors.
Its architecture replaces optocouplers with transformer-coupled signaling between LTC4270 and LTC4271, enabling galvanic isolation without isolated 3.3V supplies. The chip supports both 2-pair and 4-pair power delivery, implements rolling 1-second IPORT averaging, and features programmable fault timers (tCUT, tLIM) and DC disconnect thresholds (VMIN = 1.3–2.45 mV).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Delivered Power | 90W per port - enables LTPoE++ compliance and powers high-end PTZ cameras, wireless APs, and thin clients. |
| Detection Method | Dual-mode 4-point signature detection - combines forced voltage (7–9V) and forced current (143–180µA) for robust false-PD immunity. |
| Sense Resistor | 0.25Ω per channel - reduces heat dissipation vs. 0.5Ω alternatives and enables accurate ±1% current measurement. |
| I²C Interface Speed | Up to 1MHz - allows rapid register access for real-time port control and telemetry in dense 12-port systems. |
| Operating Temp Range | –40°C to +85°C - qualified for industrial and telecom environments including uncontrolled switch closets. |
| Package | 52-lead 7mm × 8mm QFN - exposes thermal pad (VSSK) for Kelvin-sense connection to improve current-sense accuracy. |
| Supply Voltage (VEE) | –45V to –57V relative to AGND - matches IEEE 802.3at/LTPoE++ PSE output range and supports backward compatibility. |
Pinout & Package
Package: 52-lead (7mm × 8mm) plastic QFN with exposed thermal pad (Pin 53 = VSSK). Requires Kelvin connection of VSSK to sense resistor common node-not direct VEE plane tie-down-to maintain <±0.5% current-sense accuracy.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SENSE1–SENSE12 (Pins 1,4,8,11,15,18,21,24,30,33,37,38) | Current sense input | Connects to low-side of 0.25Ω sense resistor; referenced to VEE; enables per-port overcurrent protection at VCUT = 152–168mV. |
| GATE1–GATE12 (Pins 2,5,9,12,16,19,22,25,29,32,36,39) | MOSFET gate driver output | Drives external N-channel MOSFET gate to VEE + 12V (typ); actively pulls down during fault to disable port within 6.5µs (tMSD). |
| OUT1–OUT12 (Pins 3,6,10,13,17,20,23,26,28,31,35,40) | Port voltage monitor | Reports port voltage to host; internal 500kΩ pull-up to AGND when idle; sets Power Good bit when VOUT–VEE < 2.4V. |
| VEE (Pins 41,51,52) | Main PoE negative supply input | Accepts –45V to –57V (IEEE-compliant range); absolute max rating = –0.3V to +80V relative to AGND. |
| VSSK (Pin 53, exposed pad) | Kelvin sense return | Mandatory solder connection to sense resistor common node-prevents PCB trace resistance from degrading current measurement. |
| DNA/DPA/CNA/CPA (Pins 47–50) | Transformer-coupled data/clock transceivers | Enable isolated bidirectional communication with LTC4271; eliminate need for 6 optocouplers and isolated 3.3V supply. |
Key Features
| Feature | Design Value |
|---|---|
| Transformer-isolated communication | Replaces six high-speed optocouplers and eliminates isolated 3.3V supply-reducing BOM cost and layout complexity. |
| Per-port 12-bit current monitoring ADC | Enables real-time power budgeting and diagnostics with 30.5µV/LSB resolution and 25.1ms conversion period. |
| DAC-programmable current limit | Allows dynamic adjustment of ILIM threshold (e.g., 80h = 802.3af mode, C0h = high-power mode) without hardware change. |
| 4-point PD detection | Combines forced-voltage (7–9V) and forced-current (143–180µA) signatures to reject capacitive loads and ensure >99.9% detection reliability. |
| Rolling 1-second IPORT averaging | Provides stable current readback under transient load conditions-critical for accurate power allocation in multi-PD systems. |
| Midspan mode support | Configurable via LTC4271 MID pin; includes 2-second backoff timer and 2-event classification for legacy midspan interoperability. |
Applications
| Enterprise Network Switches | Industrial PoE Midspans |
|---|---|
|
Use Scenario: 24-port managed switch powering VoIP phones, badge readers, and Wi-Fi 6 access points across mixed 802.3af/at/LTPoE++ devices. IC Role / Device Role / Timing Role: LTC4270AIUKG#PBF serves as analog PSE engine for 12 ports; manages detection, classification, power ramp, and fault response per IEEE timing specs (tDET = 220ms, tPON = 60ms). Use Value: Enables single-board 24-port design using two LTC4270AIUKG#PBF + two LTC4271 chips; eliminates optocouplers and isolated supplies, reducing layer count and cost by ~18%. |
Use Scenario: Rack-mounted midspan injector adding PoE capability to existing non-PoE Gigabit Ethernet backbone in factory automation networks. IC Role / Device Role / Timing Role: LTC4270AIUKG#PBF executes midspan-specific 2-event classification and enforces 2.3–2.7s backoff timer after failed detection per IEEE 802.3at Section 33.3.2.2. Use Value: Supports seamless integration with legacy switches; maintains full 90W LTPoE++ delivery while remaining interoperable with 13W/25.5W PDs already on site. |
| Smart Building Security Hubs | Outdoor Wireless Infrastructure |
|
Use Scenario: Centralized security gateway powering four 4K PTZ cameras (each drawing 32W), two biometric door controllers, and environmental sensors. IC Role / Device Role / Timing Role: LTC4270AIUKG#PBF provides per-port current monitoring (12-bit ADC), fast shutdown (<6.5µs), and DC disconnect (tDIS = 320–380ms) to protect against cable faults in long runs. Use Value: Enables predictive maintenance via port-by-port current trending; prevents system-wide outage when one camera shorts-only affected port shuts down. |
Use Scenario: Ruggedized outdoor enclosure housing LTE small cell + dual-band Wi-Fi 6E AP powered entirely over single Cat6a cable. IC Role / Device Role / Timing Role: LTC4270AIUKG#PBF delivers 90W using 4-pair power; handles wide-temp operation (–40°C to +85°C); monitors VEE stability during lightning-induced surges. Use Value: Eliminates separate AC feed and weatherproof conduit; supports IEEE 802.3bt-compliant power negotiation while maintaining LTPoE++ backward compatibility. |
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 LAN9355I-ABZ | Integrated 5-port PHY + PSE in single chip; max 30W/port; no LTPoE++ support; uses internal MOSFETs (no external sense resistor). | Targeted at compact embedded switches; lacks 12-port scalability and transformer isolation; unsuitable for >30W or midspan use. | Select only for space-constrained 5-port designs where integrated PHY is required and 90W delivery is unnecessary. |
| Maxim MAX5984AEUI+ | Single-port PSE controller; supports 802.3af/at only; 25.5W max; requires external optocouplers for isolation; 0.5Ω sense resistor. | Used in modular PSE add-on cards; not scalable to 12 ports without 12x ICs; higher thermal dissipation due to 0.5Ω sensing. | Choose only for low-channel-count, cost-sensitive designs where LTPoE++ and transformer isolation are not required. |
Compared with LAN9355I-ABZ and MAX5984AEUI+, the LTC4270AIUKG#PBF uniquely delivers 90W per port with transformer isolation, enabling midspan deployment and eliminating optocouplers-while supporting full IEEE 802.3at and proprietary LTPoE++ in a single 12-port analog front-end.
Availability
LTC4270AIUKG#PBF is available at Aetrix Electronics and suitable for enterprise network switches, industrial PoE midspans, and smart building security hubs requiring stable component supply, long lifecycle support, and guaranteed LTPoE++ compliance.
Supply support for LTC4270AIUKG#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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, communications, automotive, and aerospace markets.
The LTC4270AIUKG#PBF belongs to Analog Devices' Power over Ethernet (PoE) PSE controller product line, engineered specifically for high-reliability, high-power, standards-compliant power sourcing equipment in enterprise and industrial infrastructure.
FAQ
What is the maximum power delivery capability of the LTC4270AIUKG#PBF?
The LTC4270AIUKG#PBF is the A-grade variant of the LTC4270/LTC4271 chipset and supports up to 90W per port, enabling full LTPoE++ compliance. This is achieved through optimized gate drive, low-RDS(ON) MOSFET support, and 0.25Ω sense resistors-distinct from the B-grade (25.5W) and C-grade (13W) variants.
How does the LTC4270AIUKG#PBF achieve electrical isolation without optocouplers?
The LTC4270AIUKG#PBF achieves galvanic isolation via transformer-coupled signaling with the companion LTC4271 controller. Pins DNA/DPA/CNA/CPA connect to data and clock transformers, replacing up to six high-speed optocouplers and eliminating the need for an isolated 3.3V supply-reducing BOM cost and board area.
Does the LTC4270AIUKG#PBF support IEEE 802.3bt (PoE++)?
The LTC4270AIUKG#PBF implements Linear's proprietary LTPoE++ specification, which extends IEEE 802.3at with backward-compatible detection, classification, and power negotiation up to 90W. It is not IEEE 802.3bt-certified, but interoperates with 802.3af/at PDs and delivers higher power than 802.3bt Type 4 (up to 71W) via its own protocol stack.
What is the purpose of the VSSK pin (exposed pad) on the LTC4270AIUKG#PBF?
VSSK (Pin 53) is a Kelvin sense connection for the VEE return path. It must be soldered directly to the common node of the 0.25Ω sense resistor-not tied to the main VEE plane-to eliminate PCB trace resistance errors and maintain ±0.5% current measurement accuracy across temperature and load.
Can the LTC4270AIUKG#PBF operate in standalone AUTO pin mode without an I²C host?
Yes-the LTC4270AIUKG#PBF pairs with the LTC4271, whose AUTO pin enables autonomous operation. When AUTO is asserted, the LTC4271 configures default registers, allowing the LTC4270AIUKG#PBF to perform full detection, classification, and power application without I²C intervention-ideal for simple midspan or fail-safe deployments.
LTC4270AIUKG#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 52-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Controller (PSE)
- Number of Channels:
- 12
- Power - Max:
- 90 W
- Internal Switch(s):
- No
- Auxiliary Sense:
- No
- Standards:
- 802.3at (PoE+), 802.3af (PoE), LTPoE++
- Voltage - Supply:
- 45V ~ 57V
- Current - Supply:
- 9mA
- Operating Temperature:
- -40°C ~ 85°C
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 52-QFN (7x8)
LTC4270AIUKG#PBF FAQ
1.How can I place an order for LTC4270AIUKG#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4270AIUKG#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 LTC4270AIUKG#PBF reliable?
The price and inventory of LTC4270AIUKG#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4270AIUKG#PBF is usually 5 days.
3.What payment methods are accepted for LTC4270AIUKG#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4270AIUKG#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4270AIUKG#PBF?
LTC4270AIUKG#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4270AIUKG#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 LTC4270AIUKG#PBF?
For technical support, including LTC4270AIUKG#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4270AIUKG#PBF requirements.
6.How does Aetrix verify that LTC4270AIUKG#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4270AIUKG#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 LTC4270AIUKG#PBF meets industry standards.
7.What is the process for return or replacement of LTC4270AIUKG#PBF?
All LTC4270AIUKG#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4270AIUKG#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 LTC4270AIUKG#PBF part is unused and in its original packaging.
Return procedure for LTC4270AIUKG#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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