My Inquiry
My Account
Analog Devices Inc. LTC3805IMSE-5#TRPBF
- Part No.:
- LTC3805IMSE-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LTC3805IMSE-5#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:6,747
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3805IMSE-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 +125°C. It is used in automotive auxiliary power supplies requiring high-voltage input tolerance and stable regulation under transient load.
For engineers reviewing the LTC3805IMSE-5#TRPBF datasheet, LTC3805IMSE-5#TRPBF pinout, LTC3805IMSE-5#TRPBF application, or LTC3805IMSE-5#TRPBF equivalent, key selection considerations include its 10-lead MSOP package with exposed GND pad, 4.5V VCC turn-on threshold, 100mV current sense voltage drop, micropower 40µA startup current, and dual shutdown control via RUN and VCC UVLO.
Technical Context
The LTC3805IMSE-5#TRPBF implements peak current-mode control using an internal error amplifier with ITH compensation node, a programmable oscillator synchronized via SYNC pin, and independent slope compensation injected from ISENSE. Its current comparator trips when sensed voltage exceeds a threshold set by ITH voltage, enabling cycle-by-cycle current limiting.
It integrates dual undervoltage lockout: VCC UVLO (4.5V turn-on / 4.0V turn-off) and precision RUN pin control (1.207V turn-on / 1.170V turn-off with 5µA hysteresis current). Soft-start and fault timeout are jointly managed by the SSFLT pin, charged/discharged by fixed 6µA/2µA currents for programmable ramp and retry timing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VFB Accuracy | ±1.5% over –40°C to +125°C - ensures tight output regulation across full industrial temperature range without external trimming. |
| Quiescent Current | 360µA normal / 40µA micropower start-up - enables low-noise biasing and extended battery-backed operation. |
| Switching Frequency | 70kHz–700kHz via RFS - allows optimization of size vs. efficiency; supports synchronization to external clock. |
| Current Sense Threshold | 100mV typical - minimizes conduction loss in sense resistor while maintaining noise immunity. |
| VCC Shunt Regulator | 9.5V clamp (25mA max) - permits direct high-VIN biasing (e.g., 24V/48V automotive) without external LDO. |
| Overcurrent Trip | Programmable 85–115mV via OC pin resistor - provides configurable short-circuit protection with automatic restart. |
| Soft-Start Time | 1.8ms internal / externally programmable via SSFLT capacitor - prevents inrush current and enables controlled power-up sequencing. |
Pinout & Package
The LTC3805IMSE-5#TRPBF is housed in a 10-lead MSOP package with exposed thermal pad (Pin 11), rated for –40°C to +125°C operation. The exposed pad must be soldered to PCB ground for thermal performance and electrical reference.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SSFLT (1) | Soft-Start & Fault Timeout Control | Capacitor-to-GND sets soft-start ramp time and post-fault retry delay; internal 6µA charge / 2µA discharge currents. |
| ITH (2) | Error Amplifier Output / Compensation Node | 0.7V–1.9V clamped voltage controls current comparator threshold; connects to RC network for loop stability. |
| FB (3) | Feedback Input | Monitors resistive divider output; regulates VOUT to 0.8V reference with ±1.5% accuracy. |
| RUN (4) | Enable Control with Precision Threshold | 1.207V turn-on / 1.170V turn-off with 5µA hysteresis current - enables programmable VIN undervoltage lockout. |
| FS (5) | Frequency Set Input | Resistor-to-GND programs oscillator frequency from 70kHz to 700kHz per fOSC = 24×10⁹/(RFS − 1500). |
| SYNC (6) | External Clock Synchronization Input | Accepts rising-edge-triggered external clock (70–700kHz); overrides internal oscillator for EMI reduction. |
| ISENSE (7) | Current Sensing & Slope Compensation Source | Measures MOSFET source current; injects 10µA linear ramp for duty-cycle-dependent slope compensation. |
| OC (8) | Overcurrent Detection Input | Monitors same sense resistor as ISENSE; trips at programmable 85–115mV to initiate fault timeout and restart. |
| VCC (9) | Supply Input with Internal Clamp | Internally regulated to ~9.5V (25mA max sink); accepts 4.7–8.8V low-impedance or high-VIN via series resistor. |
| GATE (10) | N-Channel MOSFET Gate Driver | Push-pull output swings GND to VCC; 30ns rise/fall times into 3000pF load - drives medium-power discrete FETs. |
Key Features
| Feature | Design Value |
|---|---|
| Adjustable Frequency with Single Resistor | Enables layout- and cost-optimized magnetics selection across wide input/output ranges without changing IC. |
| Programmable Overcurrent Protection with Auto-Restart | Prevents MOSFET destruction during sustained overload or short-circuit while enabling autonomous recovery after fault timeout. |
| Low 40µA Micropower Startup Current | Reduces bias supply burden in always-on systems and extends runtime in battery-backed housekeeping rails. |
| Integrated VCC Shunt Regulator (9.5V) | Eliminates need for external LDO or Zener when deriving bias from high-VIN sources like 24V/48V automotive buses. |
| Dual Independent UVLO (VCC + RUN) | Allows flexible system-level power sequencing: VCC UVLO guards controller supply integrity; RUN UVLO enables precise input bus monitoring. |
Applications
| Automotive Auxiliary Power Supply | Telecom Housekeeping Rail |
|---|---|
Use Scenario: Generating isolated 5V/12V bias for infotainment MCU, CAN transceivers, and sensor interfaces from 12V/24V vehicle battery with cold-crank tolerance. IC Role / Device Role / Timing Role: Flyback controller managing primary-side switching, feedback isolation via optocoupler, and precise output regulation despite wide VIN variation. Use Value: ±1.5% VFB accuracy and 4.5V VCC UVLO ensure reliable startup down to 6V battery; 100mV sense threshold minimizes power loss in current sensing. | Use Scenario: Providing stable 3.3V/5V standby power for base station control logic, EEPROM, and real-time clocks during AC mains failure. IC Role / Device Role / Timing Role: Boost controller delivering regulated output from backup 12V battery or PoE-derived input, with automatic restart after brownout. Use Value: 40µA micropower startup extends battery life; programmable RUN hysteresis prevents oscillation near UVLO threshold during marginal input conditions. |
| Isolated Industrial Sensor Interface | Power over Ethernet (PoE) PD Auxiliary Supply |
Use Scenario: Creating galvanically isolated 5V rail for analog front-end amplifiers and ADCs in high-noise factory environments. IC Role / Device Role / Timing Role: SEPIC controller enabling non-inverting topology with input/output overlap, eliminating need for transformer polarity reversal. Use Value: Adjustable slope compensation (via ISENSE ramp + external resistor) stabilizes control loop at high duty cycles common in wide-input SEPIC designs. | Use Scenario: Generating local 3.3V/5V supply for PD controller, PHY, and microcontroller from PoE Class 3–5 input (37–57V). IC Role / Device Role / Timing Role: Flyback controller operating with high VIN-to-VOUT ratio, leveraging internal 9.5V VCC clamp to simplify bias winding design. Use Value: VCC shunt regulator eliminates dedicated bias winding or auxiliary converter; SYNC input enables spread-spectrum operation to meet PoE EMI requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar current-mode flyback/boost/SEPIC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3873-5#TRPBF | Fixed 5V reference (not adjustable); no SYNC pin; lower quiescent current (25µA startup). | Lacks synchronization capability and programmable frequency; better suited for cost-sensitive, fixed-frequency designs. | Select when frequency stability and EMI control are not required, and lowest possible startup current is critical. |
| UCC28085DR | Fixed 100kHz frequency; no programmable slope compensation; higher VFB tolerance (±2%). | Designed for AC-DC PFC + PWM combos; lacks independent RUN pin and micropower startup mode. | Select for integrated PFC+PWM systems where fixed frequency and TI ecosystem support are prioritized over flexibility. |
Compared with LTC3873-5#TRPBF and UCC28085DR, the LTC3805IMSE-5#TRPBF offers unique programmability in frequency, overcurrent threshold, slope compensation, and dual UVLO-making it optimal for custom isolated DC/DC designs demanding adaptability across diverse input conditions and safety requirements.
Availability
LTC3805IMSE-5#TRPBF is available at Aetrix Electronics and suitable for automotive auxiliary power supplies, telecom housekeeping rails, isolated industrial sensor interfaces, and Power over Ethernet (PoE) powered device auxiliary supplies requiring stable component supply across extended temperature and long production lifecycles.
Supply support for LTC3805IMSE-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. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3805IMSE-5#TRPBF belongs to ADI's legacy Linear Technology power management portfolio, specifically engineered for robust, flexible, and efficient isolated and non-isolated DC/DC conversion in harsh environments including automotive, industrial, and telecom infrastructure.
FAQ
What is the operating temperature range of the LTC3805IMSE-5#TRPBF?
The LTC3805IMSE-5#TRPBF is specified for operation from –40°C to +125°C junction temperature. This I-grade rating makes it suitable for under-hood automotive applications and industrial environments where ambient temperatures exceed standard commercial limits. The 10-lead MSOP package with exposed thermal pad ensures effective heat dissipation within this range.
How does the RUN pin function on the LTC3805IMSE-5#TRPBF?
The RUN pin on the LTC3805IMSE-5#TRPBF provides precision enable/disable control with a 1.207V turn-on threshold and 1.170V turn-off threshold, plus built-in 35mV hysteresis. When enabled, it sources 5µA to add user-programmable hysteresis via the external voltage divider. This allows the LTC3805IMSE-5#TRPBF to implement reliable input bus monitoring independent of VCC UVLO behavior.
Can the LTC3805IMSE-5#TRPBF be synchronized to an external clock?
Yes, the LTC3805IMSE-5#TRPBF supports external synchronization via its SYNC pin (Pin 6). A rising edge on SYNC triggers the start of each switching cycle, overriding the internal oscillator. The external clock frequency must be between 70kHz and 700kHz, matching the internal oscillator's programmable range. This feature enables EMI reduction through frequency dithering or alignment with system clocks.
What is the purpose of the SSFLT pin on the LTC3805IMSE-5#TRPBF?
SSFLT (Pin 1) on the LTC3805IMSE-5#TRPBF serves dual functions: soft-start timing and fault timeout. An external capacitor from SSFLT to GND sets both the output voltage ramp rate during startup and the delay before automatic restart after overcurrent shutdown. Internal 6µA charging and 2µA discharging currents provide predictable, temperature-stable timing without requiring additional circuitry.
Does the LTC3805IMSE-5#TRPBF require an external current sense resistor?
Yes, the LTC3805IMSE-5#TRPBF requires an external current sense resistor connected between the source of the external N-channel MOSFET and ground. This resistor feeds both the ISENSE pin (for current-mode control) and the OC pin (for overcurrent protection). The typical 100mV sense threshold minimizes power loss while maintaining sufficient signal-to-noise ratio for reliable operation in the LTC3805IMSE-5#TRPBF.
LTC3805IMSE-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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP-EP
LTC3805IMSE-5#TRPBF FAQ
1.How can I place an order for LTC3805IMSE-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3805IMSE-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 LTC3805IMSE-5#TRPBF reliable?
The price and inventory of LTC3805IMSE-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 LTC3805IMSE-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3805IMSE-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3805IMSE-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3805IMSE-5#TRPBF?
LTC3805IMSE-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3805IMSE-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 LTC3805IMSE-5#TRPBF?
For technical support, including LTC3805IMSE-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3805IMSE-5#TRPBF requirements.
6.How does Aetrix verify that LTC3805IMSE-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3805IMSE-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 LTC3805IMSE-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3805IMSE-5#TRPBF?
All LTC3805IMSE-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3805IMSE-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 LTC3805IMSE-5#TRPBF part is unused and in its original packaging.
Return procedure for LTC3805IMSE-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3805IMSE-5#TRPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
