LTC4353IMS#PBF - Dual Low Voltage Ideal Diode Controller | ADI
MPN: LTC4353IMS#PBF ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.11 | $6.11 |
| 10 | $5.75 | $57.50 |
| 100 | $5.48 | $548.00 |
| 500 | $5.34 | $2,670.00 |
| 1,000 | $5.23 | $5,230.00 |
LTC4353IMS#PBF Overview
An ideal diode controller is a power management IC that operates an external MOSFET as a near-lossless diode: the device senses the source-to-drain voltage and regulates the gate to keep the forward drop in the millivolt range. In the system hierarchy, it sits above discrete rectifiers and below full hot-swap and power ORing controllers, serving low-voltage DC rails that feed downstream DC-DC converters, voltage regulators, and point-of-load power management ICs.
Key features include the dual 2:2 channel configuration in a single MSOP-16 package, which halves the controller count of discrete solutions. According to the Analog Devices LTC4353 datasheet (document 4353f), the part regulates the forward-voltage drop across each MOSFET to ensure smooth current transfer in diode-OR applications, permitting low-loss power supply ORing and supply holdup. A fast turn-on reduces load voltage droop during supply switchover, while a fast turn-off minimizes reverse-current transients if an input supply fails or is shorted.
Technically, the LTC4353 implements a closed-loop forward-voltage regulation scheme around each N-channel MOSFET. Rather than simply amplifying the source-drain diode drop, it servos the gate so conduction transfers gradually between paralleled supplies, avoiding oscillation and current chopping. The low-voltage rating targets modern 3.3 V, 5 V, and intermediate bus rails where a Schottky diode drop of 0.4 V to 0.6 V would consume an unacceptable fraction of the margin. Because conduction loss scales with I-squared times RDS(on), a properly chosen MOSFET can cut ORing loss by a factor of five or more versus a Schottky at the same current, directly reducing heatsink size and thermal design effort.
Typical applications include redundant supply ORing in low-voltage servers and networking blades, battery and adapter power-path selection in portable and industrial equipment, and supply holdup circuits bridging brief input interruptions. In each case the fast transient response keeps the load rail stable through the switchover event.
When designing with this device, select MOSFETs for both low RDS(on) and adequate avalanche and body-diode robustness, since the controller must charge the gate quickly at turn-on; adequate ceramic decoupling at the input pins is also essential for clean switchover behavior.
This page synthesizes distributor pricing, same-family drop-in alternatives, and practical design notes not found in the manufacturer datasheet, with data verified as of 2026-10-19.
Drop-in alternatives for LTC4353IMS#PBF — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC4353CMS#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC4353HMS#PBF
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC4353IDE#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC4353IMS#PBF Maximum Ratings & Electrical Characteristics
| Function | Dual Low Voltage Ideal Diode Controller |
| Channels | 2 (2:2 ORing configuration) |
| External MOSFET Type | N-Channel |
| Package | 16-MSOP |
| Mounting Type | Surface Mount |
| Turn-Off Response | Fast (minimizes reverse-current transients per datasheet) |
| Turn-On Response | Fast (reduces load voltage droop per datasheet) |
| Applications | Diode-OR, supply holdup, power supply ORing |
| RoHS Status | Compliant (#PBF suffix = lead-free) |
| 1ku List Price | $5.23 (as of 2026-10-19, per analog.com) |
| Replaces | Two high power Schottky diodes and heat sinks |
LTC4353IMS#PBF 16-msop Pin Configuration Guide
Pin configuration for LTC4353IMS#PBF (16-msop package). This power device features gate, drain, and source terminals. For non-polarized packages, refer to the manufacturer datasheet for exact pin 1 orientation and footprint details. Common applications include power supply design, motor driving, and load switching.
No detailed pinout data available for LTC4353IMS#PBF.
Refer to the datasheet for full pin configuration.
Typical Applications
LTC4353IMS#PBF is suitable for 6 applications: Redundant Low-Voltage Supply ORing, Battery / Adapter Power-Path Selection, Supply Holdup / Ride-Through Circuits, Industrial PLC and Automation I/O Power, Telecom and Networking Line Cards, Automotive and Transportation Subsystem Rails.
Redundant Low-Voltage Supply ORing
In servers, networking blades, and telecom cards fed from redundant -48 V-derived or intermediate 5 V/12 V rails, two supplies are diode-ORed so a failed unit does not drag down the bus. The LTC4353IMS#PBF drives one N-channel MOSFET per source, regulating the forward drop to millivolts instead of the 0.4 V-0.5 V of Schottky diodes, which cuts ORing conduction loss by roughly five times at the same current. Its fast turn-on limits load voltage droop during supply switchover, keeping downstream point-of-load converters in regulation, while fast turn-off blocks reverse current when a source fails or shorts. The dual 2:2 channel integration in one 16-MSOP package halves controller count versus two single-channel ICs.
Recommended
Battery / Adapter Power-Path Selection
Portable and industrial instruments that run from either an external adapter or an internal battery need automatic, near-lossless source selection. The LTC4353IMS#PBF's two channels naturally map one to the adapter input and one to the battery, with forward-voltage regulation ensuring smooth handover as the adapter is plugged or removed. Compared with a dual-Schottky power path, the MOSFET-based approach recovers hundreds of milliwatts at multi-amp loads - directly extending battery runtime - and the fast turn-off prevents the battery from back-driving a shorted adapter. Designers should choose MOSFETs with low RDS(on) and verify gate-drive timing so switchover droop stays within the load regulator's dropout budget.
Recommended
Supply Holdup / Ride-Through Circuits
Systems requiring ride-through of brief input interruptions use a storage capacitor or secondary source held behind an ideal diode. The LTC4353IMS#PBF's ideal diode behavior permits low-loss supply holdup: the MOSFET conducts with millivolt drop during normal operation, then the fast turn-off isolates the holdup energy instantly when the primary supply fails or is shorted, per the datasheet. The regulated forward voltage also ensures the holdup capacitor charges fully rather than sitting a diode-drop below the rail, maximizing stored energy (E = 0.5*C*V^2). This function is common in industrial PLC modules and test equipment where even milliseconds of rail collapse cause processor resets.
Recommended
Industrial PLC and Automation I/O Power
PLC I/O modules and factory automation cards frequently combine a 24 V-derived logic rail with a local backup or parallel feed, and must tolerate hot-swapping of supply connectors. The LTC4353IMS#PBF, in its industrial temperature grade, controls two N-channel MOSFETs to OR these feeds with minimal dissipation - important in sealed modules where heatsinking is limited. Fast turn-off minimizes reverse-current transients when a connector is unplugged under load, protecting adjacent modules on a shared backplane rail. Replacing two Schottky diodes and heat sinks also reduces module height and improves vibration reliability by eliminating large through-hole rectifiers from the BOM.
Recommended
Telecom and Networking Line Cards
Telecom line cards distribute multiple low-voltage rails across a backplane, and each feed is typically diode-ORed at the card edge for redundancy. The LTC4353IMS#PBF suits these low-voltage rails: forward-voltage regulation gives smooth current transfer as load shares between paralleled feeds, avoiding the hunting and current chopping seen with simple comparator-based ORing. The fast turn-on characteristic reduces load voltage droop during hot insertion or feed switchover - essential for keeping ASIC and FPGA core rails above brownout thresholds. Integrating both channels in one 16-MSOP saves precious edge-card board area compared with dual discrete solutions.
Recommended
Automotive and Transportation Subsystem Rails
Transportation electronics - telematics, gateways, and infotainment clusters - often OR a primary battery feed with a crank-safe backup or auxiliary source. Using the LTC4353HMS#PBF extended-temperature variant of this family, designers keep the same 16-MSOP footprint and ideal diode function in harsh thermal environments. The MOSFET-based ORing path minimizes quiescent dissipation, which matters for always-on telematics modules drawing from battery during key-off. Fast turn-off isolates a shorted auxiliary source from the main rail, and fast turn-on prevents logic resets during cold-crank voltage excursions. Select MOSFETs rated for automotive load-dump transients and verify SOA at maximum cranking currents.
Recommended
Recommended Products Summary
Engineering reference data for LTC4353IMS#PBF — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC4353CMS#PBF | LTC4353HMS#PBF | LTC4353IDE#PBF |
|---|---|---|---|---|
| Package | 16-MSOP | 16-MSOP - same | 16-MSOP - same | 16-MSOP - same |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Channels | 2 (2:2) | 2 (2:2) | 2 (2:2) | 2 (2:2) |
| External MOSFET | N-Channel | N-Channel | N-Channel | N-Channel |
| Function | Ideal Diode / OR Controller | Ideal Diode / OR Controller | Ideal Diode / OR Controller | Ideal Diode / OR Controller |
| Operating Temperature | Industrial grade (I suffix) | Commercial grade (C suffix) | Extended high temperature (H suffix) | Industrial grade (I suffix) |
| Lead Finish | #PBF (lead-free) | #PBF (lead-free) | #PBF (lead-free) | #PBF (lead-free) |
Key Differentiators
- Dual 2:2 integration halves controller count (vs LTC4357HMS8#PBF)
- Smooth current transfer via regulated forward voltage (vs Simple comparator-based ORing controllers)
- Same-footprint temperature-grade flexibility (vs LTC4353CMS#PBF / LTC4353HMS#PBF)
Design Notes
Select external N-channel MOSFETs primarily for low RDS(on) at the available gate-drive voltage, since conduction loss is I^2 x RDS(on). Estimated: at a 5 A ORing current, a MOSFET with 10 mOhm RDS(on) dissipates about 0.25 W versus roughly 2.5 W for a 0.5 V Schottky - a tenfold reduction that eliminates the heatsink. Verify the MOSFET's gate threshold suits the LTC4353 gate-drive range and that its body diode rating covers momentary reverse conduction before the controller turns the gate off.
Place the gate-drive loop (controller GATE pin to MOSFET gate, with the source-sense path) as short as possible; long gate traces add inductance that slows the fast turn-off and can allow large reverse-current transients when a supply fails or shorts. Provide solid ground planes for the sense returns and adequate copper area under the MOSFET drains for the load current. Decouple the input supply pins with 0.1 uF ceramics placed close to the IC to keep the forward-voltage regulation loop clean during switchover.
Do not treat the LTC4353 as a hot-swap controller: it limits forward voltage across the MOSFET but does not provide current limiting or programmable inrush control - add a dedicated hot-swap device if inrush limiting is required. Also, when paralleling more than two sources, remember this is a dual 2:2 controller; cascading multiple LTC4353 devices requires verifying that regulation setpoints do not fight each other. Confirm the exact temperature-grade suffix (C/I/H) on incoming parts, since the packages are visually identical.
Compliance Information
The #PBF suffix denotes Analog Devices' lead-free (Pb-free) construction; RoHS compliant per #PBF designation. REACH and halogen-free status not stated in provided data.
