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Analog Devices Inc. LTC3803MPS6#TRPBF
- Part No.:
- LTC3803MPS6#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LTC3803MPS6#TRPBF.pdf
- Description:
- IC REG CTRLR FLYBACK TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:4,284
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Product details
Overview
LTC3803MPS6#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode flyback DC/DC controller optimized for driving external N-channel MOSFETs in high-input-voltage telecom and industrial power supplies. It delivers ±1.5% output voltage accuracy, 200kHz fixed switching frequency, 240μA quiescent current, and operates across –55°C to 150°C junction temperature. Used in nonisolated 5V/2A housekeeping supplies with 36V–72V input.
For engineers reviewing the LTC3803MPS6#TRPBF datasheet, LTC3803MPS6#TRPBF pinout, LTC3803MPS6#TRPBF application, or LTC3803MPS6#TRPBF equivalent, key selection criteria include its wide-temperature MP-grade qualification, ground-referenced current sensing enabling VIN beyond VCC limits, programmable slope compensation, internal soft-start, and compatibility with bias-winding or resistor-fed VCC architectures.
Technical Context
The LTC3803MPS6#TRPBF implements a current-mode control architecture with a 200kHz free-running oscillator, peak-current sensing via the SENSE pin, and an error amplifier that modulates the ITH/RUN voltage to set the current comparator threshold. Its internal shunt regulator clamps VCC to ~9.5V, enabling direct resistor-based powering from high VIN.
It features micropower hysteretic start-up, undervoltage lockout with 1.5V hysteresis (VTURNON = 7.6V, VTURNOFF = 6.1V), and internal soft-start with 1.4ms ramp time. The NGATE driver delivers 1A peak sink/source capability with 40ns rise/fall times into 3000pF, supporting fast-switching MOSFETs in flyback topologies.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 200kHz fixed - ensures predictable EMI profile and simplifies filter design across load range. |
| Output Voltage Accuracy | ±1.5% - enables tight regulation of 5V telecom housekeeping rails without post-regulation. |
| Quiescent Current | 240μA - minimizes no-load power loss in always-on auxiliary supplies. |
| Operating Temperature | –55°C to +150°C - qualified for extended industrial, automotive, and aerospace environments. |
| VCC Shunt Clamp | 9.5V at 25mA - allows direct resistor-fed operation from VIN up to 100V+ with passive regulation. |
| Peak Sense Voltage | 100mV (typ) - sets precise current limit with low-loss external sense resistors (e.g., 20mΩ for 5A). |
| Soft-Start Time | 1.4ms - prevents inrush current and transformer saturation during cold start. |
Pinout & Package
Package: 6-lead TSOT-23 (ThinSOT™), 1mm height, RoHS-compliant, moisture sensitivity level 1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH/RUN (1) | Error amplifier output / shutdown control | Sets current comparator threshold (0.7V–1.9V); <0.28V forces shutdown; hosts RC compensation network. |
| GND (2) | Analog and power ground reference | Common return for VFB, SENSE, and VCC bypass; must be low-impedance star point. |
| VFB (3) | Feedback input | Compares divided output voltage to 0.8V internal reference; 10nA input bias enables high-value dividers. |
| SENSE (4) | Current sense input / slope ramp injection | Measures RSENSE voltage; sources 5μA linear ramp (6%–80% duty) for external slope compensation via RSL. |
| VCC (5) | Supply input with internal shunt regulator | Accepts 7.6V–9.5V; self-regulates to ~9.5V with up to 25mA sink; requires ≥10μF local ceramic bypass. |
| NGATE (6) | N-MOSFET gate driver output | Drives external high-side switch; 0V to VCC swing, 1A peak, 40ns edges; includes blanking during switching transitions. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-frequency current mode | Eliminates subharmonic instability at >50% duty cycle and enables predictable EMI filtering without frequency dithering. |
| Ground-referenced current sensing | Allows primary-side sensing on low-side MOSFET source - supports input voltages far exceeding VCC rating (e.g., 72V VIN with 9.5V VCC). |
| Programmable slope compensation | 5μA internal ramp injected at SENSE pin enables stable operation across wide duty-cycle range using external RSL (e.g., 5.9kΩ for 30mV compensation at 80%). |
| Micropower hysteretic start-up | 0.3μA pull-up on ITH/RUN and wide UVLO hysteresis (7.6V ON / 6.1V OFF) enable reliable bootstrap start from bias winding or high-VIN resistor feed. |
| Internal soft-start | 1.4ms controlled ITH/RUN voltage ramp prevents output overshoot and limits inrush into bulk capacitors during power-up. |
Applications
| Telecom Housekeeping Supply | Automotive 42V Auxiliary Rail |
|---|---|
Use Scenario: Generating isolated 5V/2A standby power from 36V–72V telecom rectified bus for control logic and monitoring circuits. IC Role / Device Role / Timing Role: Flyback controller managing primary-side switching, current sensing, and voltage regulation without optocoupler feedback. Use Value: Enables compact, high-efficiency 5V rail with ±1.5% accuracy and no minimum load requirement - critical for low-power sleep modes. |
Use Scenario: Deriving 5V auxiliary power from 42V vehicle battery for infotainment microcontrollers and CAN transceivers. IC Role / Device Role / Timing Role: High-temperature flyback controller operating across –40°C to +125°C ambient with robust UVLO and thermal derating. Use Value: MP-grade (–55°C to +150°C) qualification ensures reliability under hood conditions; ground-referenced sensing avoids high-side current measurement complexity. |
| Power over Ethernet (PoE) PD Interface | Industrial PLC Auxiliary Power |
Use Scenario: Providing regulated 3.3V/1A or 5V/1A from PoE Class 4 (57V) input for powered device logic and PHY interfaces. IC Role / Device Role / Timing Role: Constant-frequency flyback controller implementing secondary-side regulation with minimal component count and no optocoupler. Use Value: 200kHz fixed frequency simplifies compliance with PoE EMI standards; 240μA quiescent current meets IEEE 802.3af/at no-load requirements. |
Use Scenario: Generating 12V/0.5A housekeeping supply from 24VDC industrial bus for PLC I/O modules and real-time controllers. IC Role / Device Role / Timing Role: Robust flyback controller with wide-temp MP grade and internal soft-start for immunity to brownouts and line surges. Use Value: Internal VCC shunt regulator allows direct resistor-fed operation from unregulated 24V–48V inputs - eliminates need for external LDO or buck preregulator. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3748IMS#TRPBF | Primary-side sensing with integrated transformer demagnetization detection; no optocoupler needed; higher 100V VCC rating. | Supports quasi-resonant and discontinuous conduction mode; better suited for high-efficiency isolated supplies requiring tighter cross-regulation. | Choose LT3748 for designs needing true primary-side regulation without optocoupler; LTC3803MPS6#TRPBF remains preferred for cost-sensitive, fixed-frequency flyback with proven bias-winding integration. |
| UCC28740DR | Fixed-frequency current-mode controller with integrated 700V MOSFET; lower quiescent current (120μA); no external VCC shunt required. | Targeted at low-power AC/DC adapters; lacks MP-grade temp range and ground-referenced sensing flexibility. | UCC28740DR suits sub-10W universal-input adapters; LTC3803MPS6#TRPBF is superior for high-input-voltage, wide-temp, discrete-MOSFET flyback designs where layout control and thermal management are critical. |
Compared with LT3748IMS#TRPBF and UCC28740DR, the LTC3803MPS6#TRPBF offers unique value in high-reliability, wide-temperature flyback systems requiring discrete MOSFET selection, bias-winding start-up, and ground-referenced current sensing - making it ideal for telecom, industrial, and automotive auxiliary power where long-term stability and design flexibility outweigh integration convenience.
Availability
LTC3803MPS6#TRPBF is available at Aetrix Electronics and suitable for telecom housekeeping supplies, automotive 42V auxiliary rails, and industrial PLC auxiliary power requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LTC3803MPS6#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 acquired Linear Technology in 2017 and maintains full product support, datasheets, and application engineering for legacy Linear parts including the LTC3803 family.
The LTC3803 belongs to Linear's high-voltage flyback controller product line, designed specifically for efficient, compact, and robust auxiliary power conversion in telecom, industrial, and automotive systems where input voltage exceeds standard IC supply limits.
FAQ
What is the operating temperature range of the LTC3803MPS6#TRPBF?
The LTC3803MPS6#TRPBF is an MP-grade part qualified for operation from –55°C to +150°C junction temperature. This extended range supports deployment in harsh environments such as automotive engine compartments, industrial control cabinets, and outdoor telecom equipment - unlike the E/I/H grades which max out at 125°C or 150°C with narrower low-end limits.
How does the LTC3803MPS6#TRPBF achieve stable operation without an optocoupler?
The LTC3803MPS6#TRPBF uses primary-side regulation via a resistive feedback divider referenced to the output, combined with precise 0.8V internal reference and ±1.5% accuracy. Its current-mode control and programmable slope compensation ensure loop stability across line/load variations - eliminating the need for optocoupler-based secondary feedback in many nonisolated and loosely regulated auxiliary applications.
Can the LTC3803MPS6#TRPBF be powered directly from a high input voltage like 72V?
Yes - the LTC3803MPS6#TRPBF integrates a VCC shunt regulator that clamps the supply pin to ~9.5V. By connecting a series resistor (e.g., 22kΩ) from 72V to VCC and placing ≥10μF ceramic capacitance between VCC and GND, the IC self-regulates and powers reliably. This resistor-fed method is widely used in telecom housekeeping designs per the typical application circuit.
What is the purpose of the SENSE pin on the LTC3803MPS6#TRPBF?
The SENSE pin on the LTC3803MPS6#TRPBF serves two functions: (1) it monitors voltage across an external current-sense resistor to implement peak-current limiting, and (2) it injects a 5μA linear ramp current (6%–80% duty cycle) for external slope compensation via resistor RSL - stabilizing the control loop against subharmonic oscillation in continuous conduction mode flyback designs.
Does the LTC3803MPS6#TRPBF require an external soft-start capacitor?
No - the LTC3803MPS6#TRPBF includes an internal soft-start circuit with a fixed 1.4ms ramp time. Upon exit from shutdown, the ITH/RUN voltage is clamped and gradually released, ensuring controlled gate drive turn-on and preventing output overshoot or transformer saturation - no external capacitor or timing component is needed.
LTC3803MPS6#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- SOT-23-6 Thin, TSOT-23-6
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Flyback
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 5.7V ~ 8V
- Frequency - Switching:
- 200kHz
- Duty Cycle (Max):
- 80%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable
- Operating Temperature:
- -55°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LTC3803MPS6#TRPBF FAQ
1.How can I place an order for LTC3803MPS6#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3803MPS6#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 LTC3803MPS6#TRPBF reliable?
The price and inventory of LTC3803MPS6#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3803MPS6#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3803MPS6#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3803MPS6#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3803MPS6#TRPBF?
LTC3803MPS6#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3803MPS6#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 LTC3803MPS6#TRPBF?
For technical support, including LTC3803MPS6#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3803MPS6#TRPBF requirements.
6.How does Aetrix verify that LTC3803MPS6#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3803MPS6#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 LTC3803MPS6#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3803MPS6#TRPBF?
All LTC3803MPS6#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3803MPS6#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 LTC3803MPS6#TRPBF part is unused and in its original packaging.
Return procedure for LTC3803MPS6#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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