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Analog Devices Inc. LTC3805HMSE-5#TRPBF
- Part No.:
- LTC3805HMSE-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3805HMSE-5#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,513
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Product details
Overview
LTC3805HMSE-5#TRPBF from Analog Devices (formerly Linear Technology) is a current-mode DC/DC controller IC designed to drive an external N-channel MOSFET in flyback, boost, and SEPIC topologies. It delivers ±1.5% output voltage accuracy, supports 70kHz–700kHz adjustable switching frequency via a single resistor, features programmable overcurrent protection with automatic restart, and operates across –40°C to 150°C junction temperature. It enables high-voltage input automotive auxiliary power supplies.
For engineers reviewing the LTC3805HMSE-5#TRPBF datasheet, LTC3805HMSE-5#TRPBF pinout, LTC3805HMSE-5#TRPBF application, or LTC3805HMSE-5#TRPBF equivalent, this page provides verified functional specifications, validated thermal-grade package mapping, confirmed pin roles for flyback/boost control, and real-world alternative part comparisons - all derived from official Analog Devices documentation.
Technical Context
The LTC3805HMSE-5#TRPBF implements peak current-mode control using an internal error amplifier with transconductance of 333 µA/V, a programmable oscillator with slope compensation injection (10 µA ramp), and dual threshold comparators for ISENSE and OC fault detection. Its ITH pin serves as both loop compensation node and current comparator threshold reference.
It integrates a 9.5V internal shunt regulator on VCC (clamped at 25mA max), precision RUN pin undervoltage lockout (1.207V turn-on, 1.170V turn-off), and soft-start/fault timeout timing controlled by SSFLT pin current sources (–6 µA charge, –2 µA discharge). The device supports external clock synchronization and operates without direct exposure to VIN/VOUT potentials.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Flyback, boost, SEPIC - no transformer turns ratio constraint; VIN/VOUT limited only by external components. |
| Switching Frequency | 70kHz–700kHz, set by single RFS resistor; synchronizable to external clock. |
| Output Voltage Accuracy | ±1.5% over full –40°C to 150°C operating junction range - ensures stable regulation in under-hood automotive environments. |
| Quiescent Current | 360µA normal operation; 40µA micropower startup - enables low-power housekeeping supply design. |
| Current Sense Threshold | 100mV typical peak sense voltage - minimizes power loss in external sense resistor. |
| Overcurrent Protection | Programmable OC trip level (85–115mV); automatic restart after fault timeout - prevents MOSFET damage during short-circuit events. |
| Operating Temperature | –40°C to 150°C junction - qualified for high-reliability automotive and industrial applications. |
| VCC Supply Range | 4.7V–8.8V low-impedance source; or high-VIN via resistor + internal 9.5V shunt regulator - enables flexible biasing from 12V, 24V, or 48V rails. |
Pinout & Package
Package: 10-lead plastic MSOP (MSE) with exposed pad (Pin 11 = GND). Thermal resistance θJA = 45°C/W. Exposed pad must be soldered to PCB ground for electrical integrity and thermal performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SSFLT (1) | Soft-start & fault timeout timing node | Capacitor to GND sets soft-start ramp and post-fault restart delay; internal –6µA charge / –2µA discharge currents. |
| ITH (2) | Error amplifier output / current comparator threshold | Clamped 0.7V–1.9V; connects to RC compensation network; directly sets peak switch current limit. |
| FB (3) | Feedback input | Monitors resistive divider output; regulates to 0.800V reference (H-grade); ±1.5% accuracy over full temp range. |
| RUN (4) | Enable/disable control with hysteresis | Precision thresholds: 1.207V ON / 1.170V OFF; 5µA hysteresis current enables user-programmable VIN UVLO window. |
| FS (5) | Oscillator frequency set | Resistor to GND programs fOSC = 24×10⁹/(RFS − 1500); supports 70–700kHz range. |
| SYNC (6) | External clock input | Rising edge triggers GATE high; accepts 70–700kHz external clock - enables EMI reduction via spread-spectrum sync. |
| ISENSE (7) | Current sensing & slope compensation injection | Measures MOSFET source voltage; injects 10µA linear ramp for duty-cycle-dependent slope compensation. |
| OC (8) | Overcurrent fault detection | Compares against external sense resistor; trips at 85–115mV; initiates shutdown and auto-restart sequence. |
| VCC (9) | Supply input with internal shunt regulator | Internally clamped to ~9.5V; accepts 4.7–8.8V direct or high-VIN via resistor; sinks up to 25mA. |
| GATE (10) | N-channel MOSFET gate driver | Drives external FET with 30ns rise/fall times into 3000pF load; swing = GND to VCC. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable slope compensation | 10µA programmable current ramp injected at ISENSE pin - eliminates subharmonic oscillation in >50% duty-cycle boost/flyback designs. |
| Programmable soft-start with fault timeout | Single capacitor on SSFLT controls both startup ramp and post-fault holdoff - eliminates need for external timers or microcontroller intervention. |
| High-temperature grade qualification | –40°C to 150°C guaranteed operation (H-grade) - meets AEC-Q100 stress test requirements for engine compartment power supplies. |
| Low-loss current sensing | 100mV typical ISENSE threshold - reduces sense resistor power dissipation by >50% vs. 200mV alternatives. |
| Flexible VCC biasing | Internal 9.5V shunt regulator allows direct connection to 12V/24V/48V rails via series resistor - eliminates need for dedicated LDO. |
| Precision RUN pin control | 1.207V/1.170V thresholds with 5µA hysteresis current - enables accurate, wide-range VIN undervoltage lockout without external comparators. |
Applications
| Automotive Auxiliary Power | Telecom Housekeeping Supply |
|---|---|
|
Use Scenario: Generating isolated 5V/12V bias for infotainment ECUs, ADAS sensors, or CAN transceivers from 12V battery rail with cold-crank tolerance. IC Role / Device Role / Timing Role: Primary-side controller managing flyback converter with optocoupler feedback; regulates output despite VIN sag to 4.5V. Use Value: ±1.5% regulation accuracy and –40°C to 150°C operation ensure reliable startup and runtime in under-hood environments. |
Use Scenario: Providing 3.3V/5V standby power to telecom line cards during main supply brownout or maintenance mode. IC Role / Device Role / Timing Role: Boost controller powering secondary regulators from backup battery or PoE-derived 5V rail. Use Value: 40µA micropower startup enables rapid wake-up from deep sleep; programmable UVLO prevents false turn-on during transient dips. |
| Isolated Industrial Sensor Interface | Power over Ethernet (PoE) Auxiliary Rail |
|
Use Scenario: Delivering galvanically isolated 15V/–15V analog front-end supply for current-loop transmitters in hazardous areas. IC Role / Device Role / Timing Role: Flyback controller with transformer-isolated feedback; drives discrete MOSFET for high breakdown margin. Use Value: No pin exposed to primary/secondary voltages - simplifies safety certification; 100mV current sense minimizes heat in confined enclosures. |
Use Scenario: Generating 12V auxiliary power from PoE midspan (48V) for connected lighting controllers or IoT gateways. IC Role / Device Role / Timing Role: SEPIC controller handling wide VIN variation (37–57V) while maintaining regulated output during cable drop. Use Value: Adjustable frequency avoids noise coupling into Ethernet data bands; SYNC input enables deterministic EMI alignment with PHY clocks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current-mode DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3805IMSE-5#TRPBF | Same architecture and pinout; rated for –40°C to 125°C (I-grade) instead of –40°C to 150°C (H-grade). | Not suitable for under-hood automotive use where ambient exceeds 125°C; acceptable for telecom or industrial indoor applications. | Select LTC3805HMSE-5#TRPBF when junction temperature must reach 150°C; choose I-grade for cost-sensitive non-automotive designs. |
| LTC3873-5#TRPBF | Fixed 5V reference (not adjustable); lacks SYNC input and programmable slope compensation; lower quiescent current (250µA). | Cannot support synchronized EMI reduction or high-duty-cycle boost; simpler for fixed-output, low-cost applications. | Choose LTC3873-5#TRPBF only if 5V-only output and no synchronization are acceptable; LTC3805HMSE-5#TRPBF offers broader topology and feature flexibility. |
Compared with LTC3805IMSE-5#TRPBF, the LTC3805HMSE-5#TRPBF extends guaranteed operation to 150°C junction - critical for engine bay placement - while retaining identical pinout and feature set. Versus LTC3873-5#TRPBF, it adds SYNC, slope compensation, and wider reference adjustability at the cost of slightly higher IQ, making it the only choice for demanding automotive or synchronized industrial converters.
Availability
LTC3805HMSE-5#TRPBF is available at Aetrix Electronics and suitable for automotive auxiliary power supplies, telecom housekeeping systems, isolated industrial sensor interfaces, and Power over Ethernet auxiliary rails requiring stable component supply across extended temperature ranges.
Supply support for LTC3805HMSE-5#TRPBF 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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LTC3805 family was designed specifically for rugged, high-efficiency flyback/boost/SEPIC DC/DC conversion in harsh environments - emphasizing precision control, wide temperature operation, and flexible biasing for automotive and industrial power systems.
FAQ
What is the maximum junction temperature rating for the LTC3805HMSE-5#TRPBF?
The LTC3805HMSE-5#TRPBF is specified for continuous operation from –40°C to 150°C junction temperature (H-grade). This is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics notes, where H-grade parameters are explicitly guaranteed over the full –40°C to 150°C range. The exposed pad (Pin 11) must be soldered to PCB ground to achieve the rated θJA of 45°C/W and maintain thermal performance at maximum load.
Does the LTC3805HMSE-5#TRPBF support synchronization to an external clock signal?
Yes, the LTC3805HMSE-5#TRPBF supports external clock synchronization via the SYNC pin (Pin 6). A rising edge on this pin triggers the start of each switching cycle (GATE high), enabling deterministic EMI reduction and phase alignment with system clocks. The device accepts external clock frequencies from 70kHz to 700kHz, matching its internal oscillator range, and tolerates flexible pulse widths per the datasheet's "SYNC Input" specification.
How is overcurrent protection implemented in the LTC3805HMSE-5#TRPBF?
The LTC3805HMSE-5#TRPBF implements dual-stage overcurrent protection: primary current limiting via the ISENSE pin (100mV threshold) and secondary fault detection via the OC pin (85–115mV threshold). When OC exceeds its trip point, the controller shuts down, discharges SSFLT via a 2µA current, and automatically restarts after ~4.5ms. An external resistor on OC allows adjustment of the trip level - a key differentiator from fixed-threshold controllers.
Can the LTC3805HMSE-5#TRPBF be powered directly from a 24V input rail?
Yes, the LTC3805HMSE-5#TRPBF can be powered directly from a 24V rail using a series resistor into the VCC pin. Its internal 9.5V shunt regulator safely clamps VCC and sinks up to 25mA, allowing robust biasing without an external LDO. The required resistor value is calculated as (24V − 9.5V)/25mA = 580Ω minimum; derating for temperature and tolerance is recommended per the "VCC Bias Power" section of the datasheet.
What is the purpose of the SSFLT pin on the LTC3805HMSE-5#TRPBF?
The SSFLT pin (Pin 1) on the LTC3805HMSE-5#TRPBF serves a dual function: it controls soft-start timing during power-up and fault timeout duration after overcurrent events. A capacitor from SSFLT to GND is charged at –6µA during startup (ramping GATE duty cycle) and discharged at –2µA after a fault (enabling automatic restart). Leaving SSFLT open uses internal timers (1.8ms soft-start, 4.5ms timeout), but external capacitance allows precise, application-specific timing.
LTC3805HMSE-5#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Boost, Flyback, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 3.95V ~ 9.5V
- Frequency - Switching:
- 70kHz ~ 700kHz
- Duty Cycle (Max):
- 80%
- Synchronous Rectifier:
- No
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LTC3805HMSE-5#TRPBF FAQ
1.How can I place an order for LTC3805HMSE-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3805HMSE-5#TRPBF 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 LTC3805HMSE-5#TRPBF reliable?
The price and inventory of LTC3805HMSE-5#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3805HMSE-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3805HMSE-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3805HMSE-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3805HMSE-5#TRPBF?
LTC3805HMSE-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3805HMSE-5#TRPBF 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 LTC3805HMSE-5#TRPBF?
For technical support, including LTC3805HMSE-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3805HMSE-5#TRPBF requirements.
6.How does Aetrix verify that LTC3805HMSE-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3805HMSE-5#TRPBF 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 LTC3805HMSE-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3805HMSE-5#TRPBF?
All LTC3805HMSE-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3805HMSE-5#TRPBF, 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 LTC3805HMSE-5#TRPBF part is unused and in its original packaging.
Return procedure for LTC3805HMSE-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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