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Analog Devices Inc. LTC3803HS6-3#TRPBF
- Part No.:
- LTC3803HS6-3#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LTC3803HS6-3#TRPBF.pdf
- Description:
- IC REG CTRLR FLYBACK TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:4,668
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Product details
Overview
LTC3803HS6-3#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode flyback DC/DC controller optimized for high-input-voltage N-channel MOSFET drive, delivering ±1.5% output voltage accuracy, 300 kHz fixed switching frequency, 240 μA quiescent current, and operation up to 150°C junction temperature in telecom housekeeping and automotive auxiliary power supplies.
For engineers reviewing the LTC3803HS6-3#TRPBF datasheet, LTC3803HS6-3#TRPBF pinout, LTC3803HS6-3#TRPBF application, or LTC3803HS6-3#TRPBF equivalent, key selection criteria include VCC undervoltage lockout thresholds (7.5 V turn-on / 4.0 V turn-off), programmable slope compensation via SENSE pin, internal soft-start (1.4 ms), ground-referenced current sensing, and compatibility with input voltages beyond IC absolute maximum ratings via external component selection.
Technical Context
The LTC3803HS6-3#TRPBF implements a current-mode control architecture with a 300 kHz free-running oscillator, peak-current sensing through the SENSE pin, and an error amplifier whose output at ITH/RUN sets the current comparator threshold. Its internal shunt regulator clamps VCC to ~9.5 V, enabling direct high-VIN biasing via a single resistor.
It features micropower hysteretic start-up, internal soft-start clamping of ITH/RUN for controlled ramp-up, and wide UVLO hysteresis (≥3 V) to support bootstrap operation from a flyback transformer bias winding. The NGATE driver delivers 1 A peak sink/source capability with 40 ns rise/fall times into 3000 pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 300 kHz nominal; enables compact magnetics and predictable EMI profile without frequency jitter. |
| Output Voltage Accuracy | ±1.5% over –40°C to 150°C; ensures stable regulation across extended automotive and industrial thermal environments. |
| Quiescent Current | 240 μA typical; minimizes no-load power loss in always-on auxiliary supplies. |
| VCC UVLO Thresholds | Turn-on: 7.5 V, Turn-off: 4.0 V (H-grade); supports reliable start-up and hold-off during brownout conditions. |
| Peak Sense Voltage | 85 mV (H-grade); sets current limit threshold with low-loss, high-precision external sense resistor. |
| Operating Temperature | –40°C to 150°C junction; qualified for under-hood automotive and high-reliability telecom applications. |
| Gate Drive Capability | 1 A peak NGATE sink/source; drives medium-power N-MOSFETs directly without external buffers. |
Pinout & Package
The LTC3803HS6-3#TRPBF is housed in a 6-lead ThinSOT™ (TSOT-23) package, 1 mm profile, with GND on Pin 2 and NGATE on Pin 6 for low-inductance MOSFET gate routing.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH/RUN (Pin 1) | Error amplifier output & shutdown control | Sets current comparator threshold; pulled low (<0.28 V) forces shutdown; internal 0.3 μA pull-up aids biasing. |
| GND (Pin 2) | Power and signal reference | Ground return for VCC, SENSE, VFB, and NGATE; must be low-impedance for stable current sensing. |
| VFB (Pin 3) | Feedback input | Compares output-derived voltage to 800 mV internal reference; 10 nA input current enables high-value dividers. |
| SENSE (Pin 4) | Current sense & slope compensation injection | Monitors external sense resistor voltage; sources 5 μA linear ramp for duty-cycle-dependent slope compensation. |
| VCC (Pin 5) | Supply input with internal shunt regulator | Internally clamped to ~9.5 V; accepts up to 25 mA sink current; requires ≥1 μF local ceramic bypass. |
| NGATE (Pin 6) | N-channel MOSFET gate driver | Drives gate between 0 V and VCC; 1 A peak current, 40 ns edges; designed for direct connection to MOSFET gate. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-frequency current-mode control | Enables predictable EMI filtering and stable loop compensation without subharmonic oscillation risk when slope-compensated. |
| Ground-referenced current sensing | Allows primary-side sensing with low-side resistor placement, simplifying layout and enabling input voltages exceeding VCC rating. |
| Internal shunt-regulated VCC | Permits direct high-VIN biasing via single resistor (no external LDO), reducing BOM count and cost in isolated flyback designs. |
| Micropower hysteretic start-up | Draws only 40 μA during start-up and supports bootstrap operation from bias winding-critical for high-efficiency telecom supplies. |
| Adjustable slope compensation | 5 μA programmable ramp injected at SENSE pin enables precise duty-cycle-dependent compensation using external RSL resistor. |
Applications
| Telecom Housekeeping Supply | Automotive 42V Auxiliary Power |
|---|---|
Use Scenario: Nonisolated 5 V/2 A power rail derived from 36–72 V telecom battery backup bus for baseband processor monitoring and control logic. IC Role / Device Role / Timing Role: Flyback controller regulating output via primary-side feedback, driving external N-MOSFET with NGATE, and sensing current through low-side resistor. Use Value: ±1.5% accuracy and 300 kHz operation ensure stable, low-noise supply for sensitive analog and digital circuitry without secondary-side optocoupler complexity. |
Use Scenario: Auxiliary 12 V supply for infotainment head unit powered from 42 V vehicle battery system with cold-crank tolerance down to 6 V. IC Role / Device Role / Timing Role: Constant-frequency current-mode controller managing wide VIN range, leveraging internal UVLO hysteresis and high-temp qualification. Use Value: –40°C to 150°C operation and 4.0 V turn-off threshold enable reliable start-up and hold-up during engine cranking and under-hood thermal stress. |
| Power over Ethernet (PoE) PD | Industrial Isolated Auxiliary Supply |
Use Scenario: Class 3 or 4 PoE-powered device requiring regulated 3.3 V or 5 V rail from up to 57 V PSE output, with minimal footprint and high efficiency at light load. IC Role / Device Role / Timing Role: Primary-side regulated flyback controller using bias winding for self-powered operation and ITH/RUN for precision loop control. Use Value: 240 μA quiescent current and no minimum load requirement reduce standby losses, meeting IEEE 802.3af/at efficiency mandates. |
Use Scenario: Isolated 15 V/0.5 A auxiliary supply for PLC I/O modules operating in factory environments with ambient temperatures up to 85°C and transient surges. IC Role / Device Role / Timing Role: Robust flyback controller with internal soft-start (1.4 ms) and programmable slope compensation to maintain stability across variable line/load conditions. Use Value: Internal soft-start prevents inrush current damage to transformer and output capacitors; slope compensation ensures stable operation at >50% duty cycle. |
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; 1.5% reference accuracy; 2.5 mA start-up current; no internal VCC shunt regulator. | Requires external VCC LDO or bias winding; less suitable for ultra-low-quiescent, high-VIN resistor-fed configurations. | Prefer UCC28C43DR where higher gate drive current (1.5 A) and tighter SOA protection are needed, but accept added external components. |
| MAX17595ATP+T | 4.5–60 V input range; integrated 1.2 A MOSFET driver; 300 kHz frequency; ±1% reference; no internal VCC clamp. | Designed for synchronous rectification; lacks ground-referenced sense and direct high-VIN resistor biasing capability. | Choose MAX17595ATP+T for space-constrained designs needing integrated FET drive, but verify external bias solution for >60 V inputs. |
Compared with LTC3803HS6-3#TRPBF, UCC28C43DR offers higher gate drive but demands external VCC regulation, while MAX17595ATP+T integrates more functions yet forfeits the unique ground-referenced sensing and resistor-fed simplicity critical for high-input-voltage flyback systems.
Availability
LTC3803HS6-3#TRPBF is available at Aetrix Electronics and suitable for telecom housekeeping, automotive auxiliary power, PoE powered devices, and industrial isolated auxiliary supplies requiring stable component supply across extended temperature and high-reliability requirements.
Supply support for LTC3803HS6-3#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 its legacy of high-performance analog and power management ICs with rigorous automotive and industrial qualification standards.
The LTC3803 family is designed for high-input-voltage flyback and boost DC/DC conversion in space-constrained, thermally demanding applications-including telecom, automotive, and industrial systems-where simplicity, reliability, and extended temperature operation are essential.
FAQ
What is the maximum junction temperature rating for the LTC3803HS6-3#TRPBF?
The LTC3803HS6-3#TRPBF is specified for operation from –40°C to 150°C junction temperature, qualifying it for under-hood automotive and high-ambient industrial environments. This H-grade rating is confirmed in the Absolute Maximum Ratings table and Electrical Characteristics section, where parameters like VIMAX and VFB are guaranteed over this full range.
How does the LTC3803HS6-3#TRPBF achieve stable operation without an optocoupler?
The LTC3803HS6-3#TRPBF uses primary-side regulation via a resistive feedback divider referenced to its internal 800 mV bandgap and ground-referenced current sensing. It monitors output voltage indirectly by sensing reflected voltage on the primary side during demagnetization, eliminating the need for optocouplers or secondary-side references-reducing cost and improving reliability in isolated flyback designs.
Can the LTC3803HS6-3#TRPBF be powered directly from a high input voltage like 72 V?
Yes-the LTC3803HS6-3#TRPBF features an internal VCC shunt regulator that clamps the supply to ~9.5 V and can sink up to 25 mA. This allows direct biasing from high VIN (e.g., 36–72 V telecom rails) using a single series resistor and local 1 μF bypass capacitor, as shown in Figure 3 of the datasheet-no external LDO required.
What is the purpose of the SENSE pin on the LTC3803HS6-3#TRPBF?
The SENSE pin on the LTC3803HS6-3#TRPBF serves two roles: (1) it senses voltage across an external current-sense resistor to implement peak-current-mode control, and (2) it injects a linear 5 μA ramp current used for programmable slope compensation-critical for stability at duty cycles above 50%. An external resistor (RSL) converts this current into a compensating voltage ramp.
Does the LTC3803HS6-3#TRPBF support adjustable switching frequency?
No-the LTC3803HS6-3#TRPBF operates at a fixed 300 kHz oscillator frequency, with typical variation of ±10% (270–330 kHz) over temperature and supply voltage. Frequency adjustment is not supported; the part is optimized for consistent EMI behavior and simplified magnetics design in high-input-voltage flyback applications.
LTC3803HS6-3#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:
- 300kHz
- Duty Cycle (Max):
- 80%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-6
LTC3803HS6-3#TRPBF FAQ
1.How can I place an order for LTC3803HS6-3#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3803HS6-3#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 LTC3803HS6-3#TRPBF reliable?
The price and inventory of LTC3803HS6-3#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3803HS6-3#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3803HS6-3#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3803HS6-3#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3803HS6-3#TRPBF?
LTC3803HS6-3#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3803HS6-3#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 LTC3803HS6-3#TRPBF?
For technical support, including LTC3803HS6-3#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3803HS6-3#TRPBF requirements.
6.How does Aetrix verify that LTC3803HS6-3#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3803HS6-3#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 LTC3803HS6-3#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3803HS6-3#TRPBF?
All LTC3803HS6-3#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3803HS6-3#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 LTC3803HS6-3#TRPBF part is unused and in its original packaging.
Return procedure for LTC3803HS6-3#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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