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Analog Devices Inc. LTC3803ES6-3#TRMPBF
- Part No.:
- LTC3803ES6-3#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LTC3803ES6-3#TRMPBF.pdf
- Description:
- IC REG CTRLR FLYBACK TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:2,266
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Product details
Overview
LTC3803ES6-3#TRMPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode flyback DC/DC controller in a 6-lead ThinSOT™ package, optimized for driving external N-channel MOSFETs in high-input-voltage telecom and automotive auxiliary supplies. It delivers ±1.5% output voltage accuracy, 300 kHz fixed switching frequency, 240 μA quiescent current, and operates across –40°C to 125°C. Used in nonisolated 5 V/2 A housekeeping power supplies with 36–72 V input.
For engineers reviewing the LTC3803ES6-3#TRMPBF datasheet, LTC3803ES6-3#TRMPBF pinout, LTC3803ES6-3#TRMPBF application, or LTC3803ES6-3#TRMPBF equivalent, key selection criteria include its ground-referenced current sensing architecture, programmable slope compensation via external resistor, internal soft-start (1.4 ms), micropower hysteretic start-up, and VCC shunt regulation (9.5 V clamp) enabling direct high-VIN biasing without auxiliary winding.
Technical Context
The LTC3803ES6-3#TRMPBF implements a peak-current-mode control loop with a 300 kHz free-running oscillator, internal error amplifier (200–500 μA/V transconductance), and current comparator referenced to an 800 mV internal bandgap. Its ITH/RUN pin serves dual roles: error amplifier compensation node and run/shutdown control input (0.10–0.45 V shutdown threshold).
It features wide UVLO hysteresis (VTURNON = 8.7 V, VTURNOFF = 5.7 V), adjustable slope compensation via SENSE-pin 5 μA ramp current, and NGATE driver capable of 1 A peak sink/source into 3000 pF load with 40 ns rise/fall times. The controller enforces 8–80% duty cycle limits and supports no-minimum-load operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 300 kHz nominal - ensures predictable EMI profile and simplifies filter design for telecom-grade noise compliance. |
| Output Voltage Accuracy | ±1.5% - enables tight regulation of 5 V housekeeping rails without post-regulation LDOs. |
| Quiescent Current | 240 μA - minimizes standby power loss in always-on auxiliary supplies. |
| VCC Shunt Clamp | 9.5 V typical - allows direct biasing from 36–72 V input via single dropping resistor, eliminating need for bias winding. |
| Operating Temperature | –40°C to 125°C - qualified for under-hood automotive and industrial telecom equipment environments. |
| Peak Sense Voltage | 100 mV max - sets precise current limit with low-loss external sense resistors (e.g., 68 mΩ for 1.5 A peak). |
| Soft-Start Time | 1.4 ms - prevents inrush current stress on input capacitors and transformer during cold start. |
Pinout & Package
Package: 6-lead Plastic TSOT-23 (ThinSOT™), 1 mm profile, RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH/RUN (Pin 1) | Error amplifier output & shutdown control | Sinks/sources current to set current comparator threshold; <0.28 V forces shutdown; internal 0.3 μA pull-up aids start-up. |
| GND (Pin 2) | Power and signal reference | Common return for VCC, SENSE, VFB, and NGATE; must be low-impedance connection to minimize noise coupling. |
| VFB (Pin 3) | Feedback input | Compares divided output voltage against 800 mV internal reference; 10 nA input current enables high-value divider resistors. |
| SENSE (Pin 4) | Current sensing & slope compensation injection | Monitors external sense resistor voltage; sources 0–5 μA linear ramp for duty-cycle-dependent slope compensation. |
| VCC (Pin 5) | Supply input with internal shunt regulator | Accepts 7.5–9.4 V turn-on; clamped at ~9.5 V; draws up to 25 mA to regulate from high VIN via external resistor. |
| NGATE (Pin 6) | N-channel MOSFET gate driver | Drives external FET gate from 0 V to VCC; 1 A peak current supports fast switching of low-RDS(ON) devices. |
Key Features
| Feature | Design Value |
|---|---|
| Ground-referenced current sensing | Enables high-side primary-side sensing without level-shifting circuitry, reducing component count and layout complexity in flyback topologies. |
| Programmable slope compensation | 5 μA SENSE-pin ramp + external RSL resistor stabilizes control loop at >50% duty cycle, preventing subharmonic oscillation without extra ICs. |
| Micropower hysteretic start-up | 240 μA operating ICC and <90 μA UVLO-hold current allow reliable self-start from 36–72 V using only a trickle-charge resistor and capacitor. |
| Internal soft-start | 1.4 ms controlled ITH/RUN voltage ramp limits inrush current, avoids transformer saturation, and eliminates need for external soft-start timers. |
| Wide UVLO hysteresis | 3.0 V hysteresis (8.7 V ON / 5.7 V OFF) supports stable operation when powered from transformer bias winding with variable output voltage. |
Applications
| Telecom Housekeeping Supply | Automotive Auxiliary Power |
|---|---|
Use Scenario: Nonisolated 5 V/2 A power rail for baseband processors and interface ICs in 48 V telecom systems with 36–72 V input range. IC Role / Device Role / Timing Role: Flyback controller regulating output via optocoupler-free feedback; provides gate drive timing and current limiting for primary-side N-MOSFET. Use Value: Eliminates need for isolated feedback components and bias winding, reducing BOM cost and board area by >30% versus traditional solutions. |
Use Scenario: 12 V auxiliary supply powering infotainment microcontrollers and CAN transceivers in 42 V stop-start automotive systems. IC Role / Device Role / Timing Role: Constant-frequency current-mode controller managing transient response to load steps up to 2 A while maintaining <±1.5% regulation. Use Value: 300 kHz switching enables compact magnetics; –40°C to 125°C rating ensures reliability in engine bay mounting locations. |
| Power over Ethernet PD | Industrial Control Auxiliary Rail |
Use Scenario: 5 V/1.5 A power conversion stage in IEEE 802.3af/at Powered Device (PD) interface, accepting up to 57 V input from PSE. IC Role / Device Role / Timing Role: Primary-side controller implementing detection, classification, and constant-voltage regulation without secondary-side sensing. Use Value: Ground-referenced SENSE pin simplifies PCB layout in space-constrained PD modules; low 240 μA quiescent current meets PoE standby power budgets. |
Use Scenario: 3.3 V or 5 V auxiliary supply for PLC I/O modules operating from 24 V DC industrial bus with wide temperature swings. IC Role / Device Role / Timing Role: High-efficiency flyback controller delivering stable output despite 15–36 V input variation and 0–100% load transients. Use Value: Adjustable slope compensation ensures stability across full input/output range; internal soft-start prevents nuisance tripping during brown-out recovery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28C43DR | Fixed 275 kHz frequency; no internal VCC shunt regulator; requires external bias supply; ±2% reference accuracy. | Lacks integrated VCC clamp - mandates transformer bias winding or external LDO; less suitable for ultra-simple high-VIN designs. | Select UCC28C43DR only if existing design uses external bias and tighter EMI control at 275 kHz is required. |
| MAX5021AAESA+ | 300 kHz frequency; 200 μA quiescent current; no programmable slope compensation; 8-pin SO package. | Requires external slope compensation network; larger footprint; lacks micropower start-up capability for high-VIN resistor-fed operation. | Choose MAX5021AAESA+ when SO-8 layout compatibility is mandatory and slope compensation is implemented externally. |
Compared with UCC28C43DR and MAX5021AAESA+, the LTC3803ES6-3#TRMPBF uniquely integrates VCC shunt regulation, programmable slope compensation, and micropower start-up in a 6-lead ThinSOT, enabling minimal-component, high-input-voltage flyback designs without auxiliary windings or external regulators.
Availability
LTC3803ES6-3#TRMPBF is available at Aetrix Electronics and suitable for telecom housekeeping supplies, automotive auxiliary power systems, and Power over Ethernet powered devices requiring stable component supply, extended temperature operation, and minimal external component count.
Supply support for LTC3803ES6-3#TRMPBF 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 legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification.
The LTC3803 family was designed specifically for high-input-voltage flyback and boost converters where simplicity, efficiency, and robust start-up from wide VIN ranges are critical - especially in space-constrained telecom and automotive auxiliary power applications.
FAQ
What is the maximum input voltage the LTC3803ES6-3#TRMPBF can support?
The LTC3803ES6-3#TRMPBF itself has an absolute maximum VCC rating of 8 V, but its ground-referenced current sensing and VCC shunt regulator (clamped at ~9.5 V) enable operation with input voltages up to 72 V or higher - limited only by external MOSFET, transformer, and diode ratings. In practice, the LTC3803ES6-3#TRMPBF is routinely used in 36–72 V telecom supplies and 42 V automotive systems.
Does the LTC3803ES6-3#TRMPBF require an optocoupler for feedback?
No, the LTC3803ES6-3#TRMPBF does not require an optocoupler. Its VFB pin accepts feedback from a resistive divider across the output, making it suitable for nonisolated flyback configurations like telecom housekeeping supplies. For isolated outputs, external optocoupler-based feedback remains compatible but is not mandated by the LTC3803ES6-3#TRMPBF architecture.
How does the LTC3803ES6-3#TRMPBF achieve stable operation without a bias winding?
The LTC3803ES6-3#TRMPBF achieves stable start-up and operation without a bias winding via its internal VCC shunt regulator, which draws up to 25 mA from a high-VIN supply through a single dropping resistor. This allows direct resistor-fed biasing from 36–72 V inputs - a key differentiator confirmed in the LTC3803ES6-3#TRMPBF datasheet's "Powering the LTC3803-3" section.
What is the purpose of the SENSE pin on the LTC3803ES6-3#TRMPBF?
The SENSE pin on the LTC3803ES6-3#TRMPBF performs two functions: (1) it monitors voltage across an external current-sense resistor to implement peak-current-mode control, and (2) it sources a linear 0–5 μA ramp current used for programmable slope compensation when connected to an external resistor (RSL). This dual role is explicitly documented in the LTC3803ES6-3#TRMPBF pin functions and applications information.
Can the LTC3803ES6-3#TRMPBF be used in boost converter topologies?
Yes, the LTC3803ES6-3#TRMPBF is explicitly specified for both flyback and DC/DC boost converter applications per its official description: "a constant frequency current mode flyback controller optimized for driving N-channel MOSFETs in high input voltage applications" and "designed for flyback and DC/DC boost converter applications". Its current-mode architecture and gate drive capability make it suitable for continuous-conduction-mode boost designs with appropriate external component selection.
LTC3803ES6-3#TRMPBF 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:
- 300kHz
- Duty Cycle (Max):
- 80%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LTC3803ES6-3#TRMPBF FAQ
1.How can I place an order for LTC3803ES6-3#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3803ES6-3#TRMPBF 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 LTC3803ES6-3#TRMPBF reliable?
The price and inventory of LTC3803ES6-3#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3803ES6-3#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3803ES6-3#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3803ES6-3#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3803ES6-3#TRMPBF?
LTC3803ES6-3#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3803ES6-3#TRMPBF 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 LTC3803ES6-3#TRMPBF?
For technical support, including LTC3803ES6-3#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3803ES6-3#TRMPBF requirements.
6.How does Aetrix verify that LTC3803ES6-3#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3803ES6-3#TRMPBF 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 LTC3803ES6-3#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3803ES6-3#TRMPBF?
All LTC3803ES6-3#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3803ES6-3#TRMPBF, 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 LTC3803ES6-3#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3803ES6-3#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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