LT4321IUF#TRPBF Analog Devices Integrated Circuit (Quad Flat No-Lead) In Stock
Analog Devices LT4321IUF is a PoE ideal diode bridge controller that replaces four discrete diodes with low-loss MOSFETs, reducing bridge rectifier voltage drop below 100 mV, packaged in a 16-pin QFN for IEEE 802.3at PD designs.
- Manufacturer
- Analog Devices
- Package
- Quad Flat No-Lead
- Pin Count
- 16
- Lifecycle
- ACTIVE
- Datasheet
- LT4321IUF#TRPBF Datasheet PDF
- Category
- Integrated Circuit
- Price
- From $2.2250(MOQ 19)
- Temp Range
- -40.0°C to 85.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
What are the key features of LT4321IUF#TRPBF?
- Replaces traditional diode bridge with 4 external MOSFETs, reducing voltage drop to under 100 mV versus 0.7 V per diode
- Compatible with IEEE 802.3af and 802.3at PoE Powered Device applications up to 30 W
- Gate drive circuitry controls MOSFET switching timing to prevent reverse current and inrush
- 16-pin 3 mm x 3 mm QFN package minimizes PCB area in compact PoE PD modules
- Lossless current sensing eliminates sense resistor power dissipation for higher system efficiency
What is LT4321IUF#TRPBF used for?
The LT4321IUF is used in IEEE 802.3af/at PoE Powered Device designs such as IP cameras, VoIP phones, and wireless access points where minimizing bridge rectifier power loss is critical for full PoE power budget utilization. By replacing the conventional diode bridge with four external MOSFETs, it reduces the 2.8 V combined diode drop to under 100 mV total, recovering up to 1.5 W of wasted power at 30 W input. Industrial IoT nodes and building automation controllers powered over Ethernet also benefit from the improved efficiency and thermal performance of this ideal bridge controller.
What are the specifications of LT4321IUF#TRPBF?
| Pbfree Code | No |
| Manufacturer Package Code | 05-08-1692 |
| YTEOL | 10 |
| Analog IC - Other Type | ANALOG CIRCUIT |
| JESD-30 Code | S-PQCC-N16 |
| JESD-609 Code | e3 |
| Number of Functions | 1 |
| Package Body Material | PLASTIC/EPOXY |
| Package Shape | SQUARE |
| Package Style | CHIP CARRIER, HEAT SINK/SLUG, VERY THIN PROFILE |
| Peak Reflow Temperature (Cel) | 260 |
| Supply Voltage-Max (Vsup) | 80V |
| Supply Voltage-Min (Vsup) | 20V |
| Supply Voltage-Nom (Vsup) | 55V |
| Surface Mount | YES |
| Technology | BIPOLAR |
| Temperature Grade | INDUSTRIAL |
| Terminal Finish | Matte Tin (Sn) |
| Terminal Form | NO LEAD |
| Terminal Pitch | 0.65mm |
| Terminal Position | QUAD |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| Package | Quad Flat No-Lead |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| ECCN | EAR99 |
| HTS Code | 8542.39.00.01 |
| Country of Origin | Thailand |
Where can I find the LT4321IUF#TRPBF datasheet?
LT4321IUF#TRPBF Datasheet DownloadOfficial datasheet from Analog Devices
What are equivalent replacements for LT4321IUF#TRPBF?
No known alternates. Submit an RFQ and our team can suggest alternatives.
Frequently Asked Questions
How does LT4321IUF reduce PoE bridge rectifier losses compared to a conventional diode bridge?
LT4321IUF controls 4 external N-channel MOSFETs as ideal diodes, achieving a bridge voltage drop below 100 mV versus the 1.4 V total drop of 2 series diodes in a conventional bridge. At a 500 mA load current, this saves approximately 650 mW of power dissipation, directly improving PoE PD efficiency and reducing thermal stress.
Which IEEE PoE standards does LT4321IUF support and what power levels are applicable?
LT4321IUF supports IEEE 802.3af (15.4 W) and IEEE 802.3at Type 2 (30 W) PoE Powered Device applications. The ideal diode bridge approach is especially beneficial at 30 W loads where the efficiency improvement from a sub-100 mV bridge drop versus a diode bridge is most significant in IP cameras and wireless access points.
What external components are required to build an ideal diode bridge with LT4321IUF?
An LT4321IUF-based bridge requires 4 external N-channel MOSFETs selected for low Rds(on) at the PoE input voltage of 36 V to 57 V, bootstrap capacitors for gate drive, and bulk input capacitors. The 16-pin 3 mm x 3 mm QFN footprint of LT4321IUF fits within a compact PoE PD front-end layout alongside the MOSFETs and passive components.
When should LT4321IUF be used instead of an integrated PoE PD controller with built-in bridge?
LT4321IUF is preferred when the design requires the lowest possible bridge conduction loss at 30 W PoE input and when external MOSFET selection is needed to optimize Rds(on) for specific thermal or efficiency targets. Designs with available board space for 4 discrete MOSFETs gain maximum efficiency benefit versus integrated solutions limited to fixed internal switch resistance values.
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Why Buy from FindMyChip
About Analog Devices
Analog Devices (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing integrated circuits used in virtually all types of electronic equipment.
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| Qty. | Unit Price | Ext. Price |
|---|---|---|
| 19+ | $2.6500 | $50.35 |
| 500+ | $2.2768 | $1138.39 |
| 1000+ | $2.2250 | $2225.00 |
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