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Analog Devices Inc. LTC3803IS6-5#TRMPBF
- Part No.:
- LTC3803IS6-5#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LTC3803IS6-5#TRMPBF.pdf
- Description:
- IC REG CTRLR FLYBACK TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:1,217
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Product details
Overview
LTC3803IS6-5#TRMPBF 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 isolated power supplies. It operates from 5V to 50V input, delivers ±1.5% output voltage accuracy, maintains 200kHz switching across light-to-full load, and features internal soft-start, adjustable slope compensation, and ground-referenced current sensing. It is used in telecom auxiliary supplies and PoE-powered housekeeping rails.
For engineers reviewing the LTC3803IS6-5#TRMPBF datasheet, LTC3803IS6-5#TRMPBF pinout, LTC3803IS6-5#TRMPBF application, or LTC3803IS6-5#TRMPBF equivalent, key selection criteria include its 200kHz fixed-frequency operation, 240μA quiescent current, 4.8V UVLO threshold, 6-pin ThinSOT™ package, and compatibility with high-VIN flyback topologies requiring no optocoupler third-winding feedback.
Technical Context
The LTC3803IS6-5#TRMPBF implements peak current-mode control with an internal 200kHz oscillator, error amplifier with 800mV reference, and programmable slope compensation via SENSE pin current ramp (0–5μA). Its ITH/RUN pin serves dual roles: error amplifier compensation node and shutdown control input (0.28V threshold).
It uses ground-referenced current sensing at the SENSE pin, supports VCC supply via internal shunt regulator (clamped to ~8.1V), and provides NGATE gate drive capable of sourcing/sinking 1A peak for <10μs. The device guarantees operation over –40°C to +125°C junction temperature and includes undervoltage lockout with 4.8V turn-on and 4.0V turn-off thresholds.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 200 kHz nominal; enables predictable EMI filtering and stable loop design without frequency foldback. |
| Output Voltage Accuracy | ±1.5% over temperature; ensures tight regulation for sensitive downstream logic or analog circuitry. |
| Quiescent Current | 240 μA typical; minimizes no-load power loss in always-on auxiliary supplies. |
| VCC UVLO Threshold | 4.8 V turn-on / 4.0 V turn-off; prevents unreliable MOSFET gate drive during brownout conditions. |
| Reference Voltage | 0.788–0.812 V (–40°C to +125°C); sets feedback divider ratio for precise output voltage programming. |
| Peak Sense Voltage | 100 mV typical; defines maximum switch current limit with minimal power loss in sense resistor. |
| Soft-Start Time | 0.7 ms typical; controls inrush current during power-up to avoid transformer saturation or output overshoot. |
Pinout & Package
The LTC3803IS6-5#TRMPBF is housed in a 6-lead low-profile (1mm height) TSOT-23 (ThinSOT™) package, JEDEC MO-193 compliant, with lead-free finish and tape-and-reel packaging (TRMPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH/RUN (Pin 1) | Error amplifier compensation node & shutdown control | Sinks/sources current to set current comparator threshold; pulled below 0.28V to force shutdown. |
| GND (Pin 2) | Analog and power ground reference | Common return for feedback, sense, and VCC bypass; must be low-impedance connection. |
| VFB (Pin 3) | Feedback input | Compares divided output voltage against 0.8V internal reference to regulate output. |
| SENSE (Pin 4) | Current sense and slope compensation injection | Monitors MOSFET source voltage; injects 0–5μA linear ramp for duty-cycle-dependent compensation. |
| VCC (Pin 5) | Supply input with internal shunt regulator | Accepts 5–50V input; internally clamped to ~8.1V with up to 25mA sink capability. |
| NGATE (Pin 6) | N-channel MOSFET gate driver output | Drives external high-side switch with 0V to VCC swing and 1A peak current capability. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-frequency current mode control | Enables consistent EMI signature and simplified filter design across full load range, including light loads. |
| Ground-referenced current sensing | Eliminates need for high-side current sense IC or isolated amplifiers; simplifies layout and reduces BOM cost. |
| Internal VCC shunt regulator | Permits direct biasing from high VIN through single resistor-no external LDO or preregulator required. |
| Adjustable slope compensation | Prevents subharmonic oscillation in duty cycles >50% using external RSL; starts at 6.5% duty cycle. |
| No minimum load requirement | Supports zero-load operation without instability or regulation loss-critical for standby/housekeeping rails. |
Applications
| Telecom Auxiliary Power | Power over Ethernet (PoE) Housekeeping |
|---|---|
|
Use Scenario: Providing isolated 5V/3.3V bias for PHY, MCU, and interface ICs in telecom line cards powered from 36–75V DC. IC Role / Device Role / Timing Role: Flyback controller regulating isolated secondary output; operates at fixed 200kHz for predictable noise spectrum. Use Value: 240μA quiescent current extends system standby time; ±1.5% accuracy ensures reliable logic-level compliance under varying line/load conditions. |
Use Scenario: Generating isolated 3.3V/5V for PD-side controllers and sensors in IEEE 802.3af/at-compliant PoE devices. IC Role / Device Role / Timing Role: Primary-side flyback controller eliminating optocoupler and third-winding feedback complexity. Use Value: Ground-referenced sensing and internal VCC clamp simplify PCB layout; 200kHz operation avoids interference with Ethernet data bands. |
| Automotive 12V/42V Auxiliary Supply | Industrial Isolated Sensor Bias |
|
Use Scenario: Deriving isolated 5V rail from wide-range automotive battery (6–50V) for CAN transceivers and microcontrollers. IC Role / Device Role / Timing Role: High-input-voltage flyback controller with 4.8V UVLO ensuring robust start-up during cold-crank events. Use Value: –40°C to +125°C guaranteed operation meets AEC-Q100 Grade 1 requirements; no minimum load supports intermittent sensor polling. |
Use Scenario: Powering isolated analog front-ends and signal conditioners in industrial PLC modules with 24V bus input. IC Role / Device Role / Timing Role: Compact flyback controller enabling galvanic isolation in space-constrained DIN-rail enclosures. Use Value: 6-lead ThinSOT™ package (1mm height) saves board area; 0.7ms soft-start prevents inrush-induced sensor offset drift. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3805IS6-5#TRMPBF | Adjustable frequency (100–500kHz), higher max duty cycle (90%), no internal shunt regulator on VCC. | Better suited for designs requiring EMI tuning or higher power density; requires external VCC regulation. | Select when frequency flexibility or higher peak current capability is needed; not drop-in due to VCC architecture change. |
| LTC3873IS6-5#TRMPBF | No external current sense resistor required (No RSENSE™); integrated current sense amplifier; same 200kHz fixed frequency. | Reduces component count and PCB footprint; eliminates sense resistor power loss and layout sensitivity. | Choose for lower BOM cost and improved accuracy at light loads; differs in SENSE pin function and feedback path. |
Compared with LTC3805IS6-5#TRMPBF and LTC3873IS6-5#TRMPBF, the LTC3803IS6-5#TRMPBF offers lowest quiescent current (240μA vs ≥350μA) and simplest VCC biasing, making it optimal for ultra-low-power auxiliary supplies where fixed 200kHz operation suffices.
Availability
LTC3803IS6-5#TRMPBF is available at Aetrix Electronics and suitable for telecom auxiliary power, Power over Ethernet housekeeping rails, and automotive 12V/42V auxiliary supplies requiring stable component supply and long-term lifecycle support.
Supply support for LTC3803IS6-5#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 precision analog and power management portfolio with rigorous qualification and long-term product support.
The LTC3803IS6-5#TRMPBF belongs to Linear's high-voltage flyback controller family, designed specifically for compact, isolated DC/DC conversion in telecom, industrial, and automotive systems where simplicity, low IQ, and wide input range are critical.
FAQ
What is the operating temperature range for the LTC3803IS6-5#TRMPBF?
The LTC3803IS6-5#TRMPBF is specified for operation from –40°C to +125°C junction temperature. This grade (I-grade) is validated across the full range per datasheet characterization and statistical process control, supporting use in demanding industrial and automotive environments where ambient temperatures exceed standard commercial limits.
Does the LTC3803IS6-5#TRMPBF require an external current sense resistor?
Yes, the LTC3803IS6-5#TRMPBF requires an external current sense resistor connected between the MOSFET source and ground. The SENSE pin monitors voltage across this resistor to implement peak current-mode control. Typical values range from tens of milliohms to several ohms depending on desired current limit, with 100mV full-scale sense voltage.
Can the LTC3803IS6-5#TRMPBF be powered directly from a high input voltage like 48V?
Yes, the LTC3803IS6-5#TRMPBF can be powered directly from up to 50V input via a series resistor into the VCC pin. Its internal shunt regulator clamps VCC to ~8.1V and sinks up to 25mA, eliminating the need for an external LDO or preregulator in most flyback implementations.
What is the purpose of the ITH/RUN pin on the LTC3803IS6-5#TRMPBF?
The ITH/RUN pin on the LTC3803IS6-5#TRMPBF serves two functions: it is the error amplifier output node (used for loop compensation with external RC network) and the run/shutdown control input. Pulling it below 0.28V forces shutdown; during normal operation, its voltage (0.7–1.9V) sets the current comparator threshold for PWM duty cycle.
How does slope compensation work on the LTC3803IS6-5#TRMPBF?
The LTC3803IS6-5#TRMPBF injects a linear 0–5μA current ramp from the SENSE pin starting at 6.5% duty cycle and peaking at 80%. When routed through an external resistor (RSL) to the current sense node, this creates a duty-cycle-proportional voltage that reduces the effective current limit threshold-stabilizing the control loop and preventing subharmonic oscillation.
LTC3803IS6-5#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):
- 4V ~ 8.1V
- Frequency - Switching:
- 200kHz
- 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
LTC3803IS6-5#TRMPBF FAQ
1.How can I place an order for LTC3803IS6-5#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3803IS6-5#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 LTC3803IS6-5#TRMPBF reliable?
The price and inventory of LTC3803IS6-5#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3803IS6-5#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3803IS6-5#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3803IS6-5#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3803IS6-5#TRMPBF?
LTC3803IS6-5#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3803IS6-5#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 LTC3803IS6-5#TRMPBF?
For technical support, including LTC3803IS6-5#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3803IS6-5#TRMPBF requirements.
6.How does Aetrix verify that LTC3803IS6-5#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3803IS6-5#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 LTC3803IS6-5#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3803IS6-5#TRMPBF?
All LTC3803IS6-5#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3803IS6-5#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 LTC3803IS6-5#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3803IS6-5#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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