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Analog Devices Inc. LTC3805MPMSE-5#PBF
- Part No.:
- LTC3805MPMSE-5#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3805MPMSE-5#PBF.pdf
- Description:
- IC REG CTRLR MULT TOP 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,275
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Product details
Overview
LTC3805MPMSE-5#PBF 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 one resistor, features programmable overcurrent protection with automatic restart, consumes only 360µA quiescent current in normal operation, and operates across –55°C to 150°C junction temperature - enabling use in automotive auxiliary power supplies and isolated telecom housekeeping rails.
For engineers reviewing the LTC3805MPMSE-5#PBF datasheet, LTC3805MPMSE-5#PBF pinout, LTC3805MPMSE-5#PBF application, or LTC3805MPMSE-5#PBF equivalent, key selection criteria include its 10-lead MSOP package with exposed GND pad, 4.5V VCC turn-on threshold, 100mV current sense voltage drop, RUN pin with precision hysteresis, and compatibility with high-input-voltage bias schemes using its internal 9.5V shunt regulator.
Technical Context
The LTC3805MPMSE-5#PBF implements peak-current-mode control with a programmable oscillator, integrated slope compensation current ramp (10µA), and dual-threshold RUN pin logic with 5µA hysteresis current. Its error amplifier drives the ITH node (0.7V–1.9V clamped) to set the current comparator trip point, while the OC pin provides independent overcurrent fault detection at 100mV threshold.
It supports synchronization via the SYNC pin, allows soft-start and fault timeout programming via a single capacitor on SSFLT, and uses internal UVLO (4.5V turn-on / 4.0V turn-off) plus RUN pin enable logic to manage startup sequencing. The GATE driver delivers fast rise/fall times (30ns @ 3000pF) and swings rail-to-rail between GND and VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Flyback, boost, SEPIC - no internal power switch; requires external N-MOSFET |
| Switching Frequency Range | 70kHz to 700kHz - set by single resistor on FS pin; synchronizable to external clock |
| Output Voltage Accuracy | ±1.5% - guaranteed over full –55°C to 150°C operating temperature range |
| Quiescent Current | 360µA (normal), 40µA (micropower start-up) - enables low-power standby modes |
| VCC Supply Range | 4.7V to 8.8V direct; up to >40V possible via series resistor + internal 9.5V shunt clamp |
| Current Sense Threshold | 100mV typical - low-loss sensing with minimal I²R loss in external RSENSE |
| Operating Temperature | –55°C to 150°C junction - qualified for extended-temperature automotive and industrial applications |
Pinout & Package
Package: 10-lead plastic MSOP with exposed thermal pad (Pin 11 = GND). Requires soldering of exposed pad to PCB ground plane for thermal performance and electrical reference.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SSFLT (1) | Soft-Start / Fault Timeout | Capacitor to GND sets soft-start ramp time and post-fault restart delay; also enables automatic restart after OC fault |
| ITH (2) | Error Amplifier Output | Compensation node (0.7V–1.9V clamped); sets peak current limit via current comparator threshold |
| FB (3) | Feedback Input | Monitors resistive divider output; regulates VOUT to 0.800V reference (±1.5%) |
| RUN (4) | Enable Control | Precision threshold (1.207V ON / 1.170V OFF) with 5µA hysteresis current for programmable VIN UVLO |
| FS (5) | Frequency Set | Resistor to GND programs oscillator frequency from 70kHz to 700kHz |
| SYNC (6) | External Clock Input | Accepts rising-edge-triggered external clock for synchronization; flexible pulse width |
| ISENSE (7) | Current Sense Input | Measures MOSFET source current; injects 10µA linear ramp for slope compensation |
| OC (8) | Overcurrent Fault | Detects overcurrent via separate 100mV threshold; triggers shutdown and restart timer |
| VCC (9) | Supply Input | Internally clamped to ~9.5V; accepts 4.7–8.8V direct or higher via series resistor |
| GATE (10) | MOSFET Gate Driver | Push-pull driver with 30ns rise/fall times; swings GND to VCC to drive N-MOSFET gate |
Key Features
| Feature | Design Value |
|---|---|
| Programmable Frequency | 70–700kHz via single resistor - eliminates need for multiple oscillator components |
| Adjustable Overcurrent Protection | 100mV OC threshold with external resistor scaling - enables precise fault margin setting |
| Integrated Slope Compensation | 10µA linear ramp on ISENSE pin - simplifies stable current-mode design in DCM/CCM boundary |
| Low-Power Micropower Start-Up | 40µA supply current during start-up - reduces bias power demand in high-VIN applications |
| Wide-Temperature Qualified | –55°C to 150°C operation - meets AEC-Q100 Grade 1 requirements for under-hood automotive use |
Applications
| Automotive Auxiliary Power | Telecom Housekeeping Supply |
|---|---|
Use Scenario: Generating isolated 5V/3.3V rails from 12V/24V battery for infotainment microcontrollers and CAN transceivers. IC Role / Device Role / Timing Role: Current-mode controller managing flyback converter with external N-MOSFET and transformer; regulates output via FB loop. Use Value: ±1.5% accuracy and –55°C to 150°C rating ensure reliable startup and regulation across extreme vehicle thermal cycles. |
Use Scenario: Providing bias power to control circuitry in PoE-powered switches and base station line cards where input is 48V or derived from midspan PSE. IC Role / Device Role / Timing Role: Boost controller driving external MOSFET to generate 12V/5V from 36–57V PoE input range. Use Value: Adjustable frequency (70–700kHz) allows EMI optimization; 100mV current sense minimizes conduction loss in high-current bias rails. |
| Isolated Industrial Sensors | Medical Equipment Auxiliary Rails |
Use Scenario: Powering isolated analog front-ends and ADCs in factory automation sensors requiring galvanic separation from 24V PLC bus. IC Role / Device Role / Timing Role: SEPIC controller delivering non-inverting isolated output without transformer winding polarity constraints. Use Value: Programmable RUN pin hysteresis prevents false shutdown during transient brownouts on noisy industrial 24V lines. |
Use Scenario: Generating low-noise 3.3V/5V rails for patient-monitoring microcontrollers and isolated communication interfaces in Class II medical devices. IC Role / Device Role / Timing Role: Flyback controller with external MOSFET and safety-rated transformer; regulated via optocoupler feedback. Use Value: Soft-start capacitor on SSFLT ensures controlled ramp-up of isolated outputs - critical for meeting IEC 60601-1 leakage and surge immunity requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current-mode flyback/boost controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3751IMSE#PBF | Higher VCC rating (100V), integrated high-side gate driver, fixed 100kHz frequency | Designed for active clamp forward and flyback with primary-side sensing; lacks programmable frequency and RUN hysteresis | Choose for high-input-voltage (>60V) flyback where integrated driver simplifies layout, but not for frequency-tuned or wide-temp designs |
| UCC28086D | Fixed 1MHz frequency, lower temp grade (–40°C to 125°C), no internal VCC shunt regulator | Requires external bias supply; optimized for cost-sensitive telecom brick applications with tight board space | Choose when high-frequency operation and BOM cost outweigh need for temperature robustness and self-bias flexibility |
Compared with LT3751IMSE#PBF and UCC28086D, the LTC3805MPMSE-5#PBF uniquely combines extended temperature qualification (–55°C to 150°C), programmable frequency, internal VCC shunt regulation for high-VIN bias, and precision RUN pin hysteresis - making it optimal for ruggedized, thermally demanding flyback/boost systems where design flexibility and reliability are prioritized over integration or raw frequency.
Availability
LTC3805MPMSE-5#PBF is available at Aetrix Electronics and suitable for automotive auxiliary power supplies, telecom housekeeping rails, and isolated industrial sensor modules requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3805MPMSE-5#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 and maintains its high-performance analog and power management portfolio with rigorous qualification standards.
The LTC3805MPMSE-5#PBF belongs to Linear's precision current-mode controller family, engineered specifically for rugged flyback, boost, and SEPIC converters in automotive, industrial, and telecom infrastructure where extended temperature operation and programmable protection are essential.
FAQ
What is the maximum input voltage the LTC3805MPMSE-5#PBF can support?
The LTC3805MPMSE-5#PBF itself has no intrinsic VIN limit - its pins are isolated from input/output voltages. When powered via a resistor from high VIN to VCC, the internal 9.5V shunt regulator allows safe operation from inputs exceeding 40V, provided the resistor limits VCC current to ≤25mA. External MOSFET, transformer, and diode ratings determine actual system VIN capability. The LTC3805MPMSE-5#PBF datasheet confirms this architecture enables "VIN and VOUT limited only by external components."
Does the LTC3805MPMSE-5#PBF require an external MOSFET?
Yes, the LTC3805MPMSE-5#PBF is a controller-only IC with no integrated power switch. It drives an external N-channel MOSFET via its GATE pin. This architecture allows designers to select MOSFETs optimized for voltage, current, RDS(ON), and thermal performance per application - a key requirement for flyback, boost, and SEPIC topologies covered in the LTC3805MPMSE-5#PBF datasheet and typical applications.
How does the RUN pin hysteresis work on the LTC3805MPMSE-5#PBF?
The LTC3805MPMSE-5#PBF RUN pin has built-in 35mV hysteresis (1.207V ON / 1.170V OFF) and sources 5µA when enabled. This current flows through the external voltage divider, adding programmable hysteresis: falling VIN threshold depends on R1 value. For example, with R1 = 100kΩ, additional hysteresis is ~0.5V. This prevents oscillation during slow-rising or noisy input conditions - a verified behavior documented in the LTC3805MPMSE-5#PBF Applications Information section.
Can the LTC3805MPMSE-5#PBF be synchronized to an external clock?
Yes, the LTC3805MPMSE-5#PBF supports synchronization via its SYNC pin. A rising edge on SYNC triggers the start of each switching cycle (GATE high), allowing alignment with system clocks or other converters to reduce EMI. The external clock frequency must be within 70kHz–700kHz, matching the LTC3805MPMSE-5#PBF's programmable oscillator range. This feature is explicitly confirmed in the LTC3805MPMSE-5#PBF datasheet's TYPICAL APPLICATIONS and ELECTRICAL CHARACTERISTICS tables.
What is the purpose of the SSFLT pin on the LTC3805MPMSE-5#PBF?
The SSFLT pin on the LTC3805MPMSE-5#PBF serves dual functions: soft-start timing and fault timeout. An external capacitor from SSFLT to GND controls both the output voltage ramp rate during startup and the delay before automatic restart after an overcurrent fault. During soft-start, a 6µA current charges the capacitor; during fault timeout, a 2µA current discharges it. This integrated dual-use design eliminates separate timing components - a key feature highlighted in the LTC3805MPMSE-5#PBF block diagram and OPERATION section.
LTC3805MPMSE-5#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LTC3805MPMSE-5#PBF FAQ
1.How can I place an order for LTC3805MPMSE-5#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3805MPMSE-5#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 LTC3805MPMSE-5#PBF reliable?
The price and inventory of LTC3805MPMSE-5#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3805MPMSE-5#PBF is usually 5 days.
3.What payment methods are accepted for LTC3805MPMSE-5#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3805MPMSE-5#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3805MPMSE-5#PBF?
LTC3805MPMSE-5#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3805MPMSE-5#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 LTC3805MPMSE-5#PBF?
For technical support, including LTC3805MPMSE-5#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3805MPMSE-5#PBF requirements.
6.How does Aetrix verify that LTC3805MPMSE-5#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3805MPMSE-5#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 LTC3805MPMSE-5#PBF meets industry standards.
7.What is the process for return or replacement of LTC3805MPMSE-5#PBF?
All LTC3805MPMSE-5#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3805MPMSE-5#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 LTC3805MPMSE-5#PBF part is unused and in its original packaging.
Return procedure for LTC3805MPMSE-5#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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