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Analog Devices Inc. LTC4354CS8#PBF
- Part No.:
- LTC4354CS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- OR Controllers, Ideal Diodes
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC4354CS8#PBF.pdf
- Description:
- IC OR CTRLR SRC SELECT 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,511
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Product details
Overview
LTC4354CS8#PBF from Analog Devices (formerly Linear Technology) is a negative-voltage diode-OR controller that drives two external N-channel MOSFETs to replace Schottky diodes in –48V distributed power systems. It provides 30mV source-drain voltage regulation, sub-1µs fault turn-off, and open-drain FAULT output for failure indication - enabling high-reliability redundancy in telecom infrastructure and AdvancedTCA systems.
For engineers reviewing the LTC4354CS8#PBF datasheet, LTC4354CS8#PBF pinout, LTC4354CS8#PBF application, or LTC4354CS8#PBF equivalent, key selection criteria include its –48V operation capability, 80V absolute max drain input rating, selectable fault threshold (260mV typ), gate drive compliance with standard-threshold N-MOSFETs, and SO-8 package compatibility with industrial temperature range (0°C to 70°C).
Technical Context
The LTC4354CS8#PBF implements dual independent servo loops that regulate VSD across each N-MOSFET to 30mV during forward conduction using GA/GB outputs, ensuring smooth current switchover without oscillation between parallel –48V supplies. Its internal shunt regulator clamps VCC to 11V (typ) from a resistor-fed –48V_RTN supply, eliminating need for external bias rails.
Fault detection operates at two levels: reverse-current turn-off triggers when VSD ≤ –140mV (ensuring <1µs gate discharge), while FAULT pin assertion occurs when VSD ≥ 260mV - indicating MOSFET short, open, or supply failure. Both DA and DB inputs tolerate up to 80V, with Kelvin-sensing support via dedicated VSS pins (2 & 5).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VSD Regulation Threshold | 30mV - sets minimum on-resistance operating point to minimize conduction loss while avoiding false turn-off under light load |
| Fault Detection Threshold | 260mV (typ) - triggers FAULT pin high-impedance state to illuminate LED/opto-coupler upon MOSFET failure or cross-conduction |
| Gate Turn-Off Time | 0.7–1.2µs - limits peak reverse fault current to safe levels before MOSFET thermal runaway occurs | VCC Operating Range | 4.5V to 11V - accommodates resistor-fed bias from –48V_RTN with internal 11V shunt clamp, enabling single-supply operation |
| Drain Input Voltage Rating | –0.3V to +80V - supports direct connection to –48V rails and withstands transient spikes up to 80V without external protection |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade telecom and server applications where ambient does not exceed 70°C |
| Package | 8-Lead Plastic SO (Narrow, 0.150") - industry-standard footprint compatible with automated assembly and thermal management via exposed pad (VSS) |
Pinout & Package
Package: 8-Lead Plastic Small Outline (SO-8, Narrow, 0.150"), JEDEC MS-012AC, exposed pad connected to VSS.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DA (Pin 1) | Drain A Voltage Sense Input | Kelvin-senses source-drain voltage of first N-MOSFET; requires external 2kΩ resistor for transient protection in –48V systems |
| VSS (Pin 2) | Negative Supply Reference / Common Source Node | Connects to common source of both N-MOSFETs and serves as reference for servo amplifiers; Kelvin routing critical for accuracy |
| VCC (Pin 3) | Positive Bias Input | Supplied via current-limiting resistor from –48V_RTN; internally clamped to 11V; bypass with 1µF capacitor to VSS |
| GA (Pin 4) | Gate Drive Output A | Pulls high to ≥10V to fully enhance N-MOSFET; actively servos gate to maintain 30mV VSD; pulls low to VSS in <1µs on reverse fault |
| DB (Pin 8) | Drain B Voltage Sense Input | Identical function to DA; must be routed with matched trace length and impedance for balanced channel performance |
| FAULT (Pin 7) | Open-Drain Fault Indicator | Sinks current to illuminate LED/opto-coupler during normal operation; goes high-Z to activate indicator on MOSFET failure |
| GB (Pin 6) | Gate Drive Output B | Functionally identical to GA; independent control enables true dual-channel ORing without cross-talk |
| VSS (Pin 5) | Secondary Negative Supply Reference | Dedicated Kelvin sense path to common source node; must be routed separately from Pin 2 for precision regulation |
Key Features
| Feature | Design Value |
|---|---|
| Sub-1µs fault turn-off | 0.7–1.2µs gate discharge prevents destructive reverse current in –48V systems during supply short events |
| 30mV VSD servo regulation | Maintains optimal MOSFET RDS(ON) utilization across load range, reducing conduction loss vs fixed-gate solutions |
| 80V drain input rating | Eliminates need for external TVS or Zener clamps in telecom-grade –48V applications with high-energy transients |
| Open-drain FAULT output | Directly interfaces with LED indicators or opto-isolators for system-level fault reporting without level-shifting circuitry |
| SO-8 commercial temperature grade | Enables drop-in replacement of legacy diode-OR designs in existing PCB layouts targeting 0°C to 70°C ambient |
Applications
| AdvancedTCA Shelf Power | –48V Telecom Distribution |
|---|---|
|
Use Scenario: Redundant –48V power feeds from dual rectifiers feed a single backplane bus in carrier-grade AdvancedTCA shelves. IC Role / Device Role / Timing Role: LTC4354CS8#PBF acts as intelligent ORing controller, selecting the more negative supply while preventing reverse current flow during failure. Use Value: Eliminates 0.4V Schottky forward drop per rail, saving >3W per 10A channel and removing heat sink requirements in confined shelf space. |
Use Scenario: Parallel –48V battery banks and rectifier outputs feed telecom line cards requiring uninterrupted DC power. IC Role / Device Role / Timing Role: LTC4354CS8#PBF continuously monitors VSD across two N-MOSFETs, enabling seamless switchover within 1ms during primary supply brownout. Use Value: Achieves <1µs fault response to prevent cross-conduction damage when one battery bank fails shorted to return. |
| Server Midplane Redundancy | Optical Network Shelf Power |
|
Use Scenario: Dual –48V PSUs feed a server midplane with hot-swap capability and load-sharing requirements. IC Role / Device Role / Timing Role: LTC4354CS8#PBF regulates gate drive to balance current between MOSFETs based on RDS(ON) and supply impedance, avoiding oscillation. Use Value: Enables precise current sharing without external op-amps or complex compensation, reducing BOM count and layout area by 40% vs discrete solutions. |
Use Scenario: Optical line terminals (OLTs) use redundant –48V inputs to power PON splitters and transceivers in outside plant cabinets. IC Role / Device Role / Timing Role: LTC4354CS8#PBF provides fault-latched LED indication via FAULT pin, supporting remote diagnostics without host processor intervention. Use Value: FAULT pin's open-drain architecture allows direct connection to cabinet status LEDs, cutting diagnostic wiring and firmware overhead. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar negative-voltage diode-OR controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC4354IS8#PBF | Same functionality and pinout; rated for –40°C to 85°C industrial temperature range | Required for outdoor telecom cabinets or industrial servers with extended ambient requirements | Select when operating temperature exceeds 70°C or storage below 0°C is needed |
| LT4351IMS#PBF | Single-channel, 1.2V–18V input range; no internal shunt regulator; requires external VCC supply | Designed for low-voltage systems (e.g., 3.3V/5V/12V rails); not rated for –48V operation | Use only in positive-rail or low-voltage negative-rail applications; not a drop-in replacement for –48V systems |
Compared with LTC4354CS8#PBF, the LTC4354IS8#PBF offers extended temperature capability without design changes, while LT4351IMS#PBF serves fundamentally different voltage domains and requires full schematic revision - making LTC4354CS8#PBF the sole validated solution for commercial-grade –48V ORing.
Availability
LTC4354CS8#PBF is available at Aetrix Electronics and suitable for AdvancedTCA systems, –48V distributed power systems, and telecom infrastructure requiring stable component supply with lead-free compliance and tape-and-reel packaging.
Supply support for LTC4354CS8#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; Linear pioneered high-performance analog ICs for power management, signal conditioning, and interface applications.
The LTC4354CS8#PBF belongs to Linear's Hot Swap™ and PowerPath™ product lines, engineered specifically for high-reliability ORing and fault-protected power distribution in telecom and computing infrastructure.
FAQ
What is the maximum drain voltage the LTC4354CS8#PBF can handle?
The LTC4354CS8#PBF supports drain input voltages from –0.3V to +80V on DA and DB pins. This 80V absolute maximum rating enables direct interface with –48V telecom rails while surviving transient spikes up to 80V without external clamping components - a key advantage over lower-voltage controllers like LT4351.
How does the LTC4354CS8#PBF achieve smooth current switchover between two –48V supplies?
The LTC4354CS8#PBF uses dual independent servo amplifiers to regulate the source-drain voltage (VSD) across each N-MOSFET to 30mV during forward conduction. By dynamically adjusting GA and GB gate drive voltages, it balances load current proportionally to MOSFET RDS(ON) and supply impedance - eliminating oscillation and ensuring monotonic transfer even when supply voltages differ by <100mV.
What is the purpose of the FAULT pin on the LTC4354CS8#PBF?
The FAULT pin on the LTC4354CS8#PBF is an open-drain output that sinks current during normal operation and goes high-impedance when a fault is detected - such as MOSFET short, MOSFET open, or excessive VSD (>260mV). This directly drives an LED or opto-coupler for visual or isolated system-level fault reporting without additional driver circuitry.
Can the LTC4354CS8#PBF operate without an external current-limiting resistor on VCC?
No - the LTC4354CS8#PBF requires an external current-limiting resistor between the –48V return (–48V_RTN) and VCC pin. The internal shunt regulator clamps VCC to ~11V but draws up to 2mA; omitting the resistor risks exceeding absolute maximum ratings. For a –48V rail, a 12kΩ resistor delivers ~2mA while limiting power dissipation to <0.32W.
What MOSFET parameters are critical when selecting devices for use with the LTC4354CS8#PBF?
Three MOSFET parameters are critical for LTC4354CS8#PBF: (1) VDSS > 80V to withstand fault transients, (2) RDS(ON) low enough to keep VSD < 260mV at max load (e.g., ≤52mΩ at 5A), and (3) gate threshold voltage compatible with 10–12V gate drive - standard logic-level or standard-threshold N-MOSFETs (e.g., IRF3710S, Si4466DY) are fully supported.
LTC4354CS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Source Selector Switch
- FET Type:
- N-Channel
- Ratio - Input:Output:
- 2:1
- Internal Switch(s):
- No
- Delay Time - ON:
- -
- Delay Time - OFF:
- 700 ns
- Current - Output (Max):
- -
- Current - Supply:
- 1.2 mA
- Voltage - Supply:
- -48V
- Applications:
- -48V Dist Power Systems, AdvancedTCA® Systems
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC4354CS8#PBF FAQ
1.How can I place an order for LTC4354CS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC4354CS8#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 LTC4354CS8#PBF reliable?
The price and inventory of LTC4354CS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC4354CS8#PBF is usually 5 days.
3.What payment methods are accepted for LTC4354CS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC4354CS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC4354CS8#PBF?
LTC4354CS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC4354CS8#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 LTC4354CS8#PBF?
For technical support, including LTC4354CS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC4354CS8#PBF requirements.
6.How does Aetrix verify that LTC4354CS8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC4354CS8#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 LTC4354CS8#PBF meets industry standards.
7.What is the process for return or replacement of LTC4354CS8#PBF?
All LTC4354CS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC4354CS8#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 LTC4354CS8#PBF part is unused and in its original packaging.
Return procedure for LTC4354CS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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