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Analog Devices Inc. LTC3803ES6-5#TRMPBF
- Part No.:
- LTC3803ES6-5#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-6 Thin, TSOT-23-6
- Datasheet:
-
LTC3803ES6-5#TRMPBF.pdf
- Description:
- IC REG CTRLR FLYBACK TSOT23-6
- Quantity:
- Payment:
- Shipping:
Inventory:4,707
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Product details
Overview
LTC3803ES6-5#TRMPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode flyback DC/DC controller in a 6-lead SOT-23 (ThinSOT™) package, optimized for driving N-channel MOSFETs in high-input-voltage isolated power supplies. It operates from 5V minimum input, delivers ±1.5% output voltage accuracy, maintains 200kHz fixed switching frequency down to light loads, and features ground-referenced current sensing with programmable slope compensation via external resistor.
For engineers reviewing the LTC3803ES6-5#TRMPBF datasheet, LTC3803ES6-5#TRMPBF pinout, LTC3803ES6-5#TRMPBF application, or LTC3803ES6-5#TRMPBF equivalent, key selection criteria include its 4.8V undervoltage lockout threshold, 240μA quiescent current, internal soft-start, adjustable slope compensation, and compatibility with wide VIN/VOUT ranges defined solely by external components-not IC limits.
Technical Context
The LTC3803ES6-5#TRMPBF implements peak current-mode control with a 200kHz free-running oscillator, 6.5–80% duty cycle range, and internal 0.8V reference. Its error amplifier drives the ITH/RUN pin to set the current comparator threshold, closing the regulation loop via feedback from VFB.
It integrates an internal shunt regulator (clamping VCC to ~8.1V), undervoltage lockout (4.8V turn-on / 4.0V turn-off), and a 5μA linear ramp injected at the SENSE pin for slope compensation-programmable via external RSL to stabilize operation above 50% duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 200 kHz fixed; enables predictable EMI filtering and stable light-load performance without frequency foldback. |
| Output Voltage Accuracy | ±1.5% over temperature; ensures tight regulation for sensitive downstream circuitry without trimming. |
| Quiescent Current | 240 μA typical; minimizes no-load power loss in always-on auxiliary/housekeeping supplies. |
| VCC UVLO Threshold | 4.8 V turn-on / 4.0 V turn-off; prevents unreliable gate drive during brownout conditions. |
| Peak Sense Voltage | 100 mV typical; sets current limit with low-loss, high-precision external sense resistors (e.g., 0.02Ω for 5A peak). |
| Operating Temp Range | –40°C to +125°C junction; qualified for industrial and automotive under-hood auxiliary power applications. |
| Gate Drive Rise/Fall | 40 ns each into 3000 pF; supports fast-switching MOSFETs while limiting dV/dt-induced noise. |
Pinout & Package
The LTC3803ES6-5#TRMPBF is housed in a low-profile (1.0 mm max height) 6-lead TSOT-23 (S6) package, JEDEC MO-193 compliant, with lead-free finish and tape-and-reel packaging (#TRMPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ITH/RUN (1) | Error amplifier output & shutdown control | Sets current comparator threshold; pulled up internally to ~0.7V on startup; <0.28V forces shutdown. |
| GND (2) | Power and signal reference | Common return for VCC bypass, current sense, and feedback network; must be low-impedance. |
| VFB (3) | Feedback input | Compares divided output voltage against 0.8V internal reference; 10 nA input bias enables high-resistor-divider designs. |
| SENSE (4) | Current sense & slope ramp injection | Monitors MOSFET source voltage; injects 5 μA linear ramp for duty-cycle-dependent slope compensation. |
| VCC (5) | Supply input with shunt regulator | Internally clamped to ~8.1V; accepts up to 25 mA shunt current from high-VIN resistor feed. |
| NGATE (6) | N-channel MOSFET gate driver | 0 V to VCC swing; 1 A peak sink/source capability; 40 ns rise/fall into 3000 pF load. |
Key Features
| Feature | Design Value |
|---|---|
| Constant-frequency current mode | Enables consistent EMI profile and superior line/load transient response vs. voltage-mode controllers. |
| Ground-referenced current sensing | Eliminates need for high-side sense amplifiers; allows input voltages far exceeding VCC absolute maximum rating. |
| Internal soft-start (0.7 ms) | Prevents inrush current and output overshoot during power-up without external components. |
| Adjustable slope compensation | External RSL resistor tailors compensation to transformer turns ratio and operating duty cycle, preventing subharmonic oscillation. |
| No minimum load requirement | Supports zero-load operation in standby modes-critical for PoE and telecom housekeeping rails. |
Applications
| Telecom Housekeeping Supply | Automotive Auxiliary Power |
|---|---|
Use Scenario: Isolated 12V/100mA auxiliary rail in 36–75V telecom rectifier systems. IC Role / Device Role / Timing Role: Flyback controller regulating secondary-side output using optocoupler feedback; 200kHz timing sets transformer size and filter component values. Use Value: ±1.5% accuracy and 240μA IQ ensure stable bias for control ICs and monitoring circuits across wide temperature and input variation. | Use Scenario: 5V/1.2A isolated supply for infotainment microcontrollers in 12V/42V dual-battery vehicles. IC Role / Device Role / Timing Role: Primary-side flyback controller with ground-referenced sensing; 4.8V UVLO prevents operation during cranking dips. Use Value: Wide –40°C to +125°C rating and internal shunt regulator enable direct VIN connection without external LDO-reducing BOM count. |
| Power over Ethernet (PoE) | Industrial Isolated Sensor Interface |
Use Scenario: 3.3V/3A isolated DC/DC stage in IEEE 802.3af/at PD (Powered Device) equipment. IC Role / Device Role / Timing Role: Constant-frequency flyback controller driving synchronous rectification; 200kHz frequency balances efficiency and transformer size. Use Value: Programmable slope compensation ensures stability across full 18–72V input range and varying load conditions per PoE classes. | Use Scenario: 15V isolated bias for analog front-end op-amps and ADCs in high-noise factory automation systems. IC Role / Device Role / Timing Role: Flyback controller implementing reinforced isolation barrier; ground-referenced sensing avoids floating sense circuitry. Use Value: 0.8V reference and ±1.5% accuracy maintain precise sensor excitation voltage despite long cable runs and ground potential differences. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar flyback controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3805ES6-5#TRMPBF | Adjustable 100–500kHz frequency; higher 350μA IQ; same SOT-23 package and pinout. | Preferred where EMI tuning or higher frequency (smaller magnetics) is required; less suitable for ultra-low-IQ standby. | Select LTC3803ES6-5#TRMPBF when fixed 200kHz, lowest IQ, and proven stability in telecom/housekeeping designs are prioritized. |
| LTC3873ES6-5#TRMPBF | No external current sense resistor needed (No RSENSE™); 250μA IQ; same 200kHz frequency and SOT-23 package. | Better for cost-sensitive, space-constrained designs eliminating RSENSE and its PCB layout sensitivity. | Choose LTC3803ES6-5#TRMPBF when design requires precise, adjustable current limiting or compatibility with legacy RSENSE-based layouts. |
Compared with LTC3805ES6-5#TRMPBF and LTC3873ES6-5#TRMPBF, the LTC3803ES6-5#TRMPBF offers the lowest quiescent current and fixed 200kHz operation-ideal for stable, low-noise, always-on auxiliary supplies where frequency agility or sense-resistor elimination are not required.
Availability
LTC3803ES6-5#TRMPBF is available at Aetrix Electronics and suitable for telecom housekeeping supplies, automotive auxiliary power rails, and Power over Ethernet (PoE) powered devices requiring stable component supply, extended temperature support, and low-quiescent-current operation.
Supply support for LTC3803ES6-5#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 full product support, manufacturing, and documentation for the LTC portfolio.
The LTC3803 series is designed specifically for compact, high-efficiency isolated flyback, SEPIC, and boost converters in space-constrained industrial, telecom, and automotive auxiliary power applications.
FAQ
What is the recommended input voltage range for reliable operation of the LTC3803ES6-5#TRMPBF?
The LTC3803ES6-5#TRMPBF operates from a minimum input of 5V and supports inputs up to the breakdown rating of external components. Its VCC pin features an internal shunt regulator clamped at ~8.1V, allowing direct connection to high VIN (e.g., 48V or 72V) via a series resistor. The 4.8V undervoltage lockout ensures robust start-up even during input dips.
How does the LTC3803ES6-5#TRMPBF achieve stable operation at duty cycles above 50%?
The LTC3803ES6-5#TRMPBF injects a linear 5μA ramp current through the SENSE pin into an external resistor (RSL), generating a duty-cycle-proportional voltage that adds to the current sense signal. This slope compensation stabilizes the current-mode control loop and prevents subharmonic oscillation-critical for flyback topologies operating near or above 50% duty cycle.
Can the LTC3803ES6-5#TRMPBF be used in non-isolated boost configurations?
Yes, the LTC3803ES6-5#TRMPBF is explicitly specified for boost, SEPIC, and flyback topologies. Its ground-referenced current sensing and flexible feedback architecture allow straightforward implementation in non-isolated boost converters-provided external components (MOSFET, diode, inductor) are rated for the application's voltage and current requirements.
What is the purpose of the ITH/RUN pin on the LTC3803ES6-5#TRMPBF, and how is it used?
The ITH/RUN pin on the LTC3803ES6-5#TRMPBF serves dual roles: it is the error amplifier output that sets the current comparator threshold, and it functions as the run/shutdown control input. Pulling ITH/RUN below 0.28V forces shutdown; during normal operation, its voltage (0.7–1.9V) directly controls peak switch current and thus output regulation. An external RC network here provides loop compensation.
Does the LTC3803ES6-5#TRMPBF require an external current sense resistor, and what is its typical value range?
Yes, the LTC3803ES6-5#TRMPBF requires an external current sense resistor (RSENSE) connected between the MOSFET source and ground. Typical values range from tens of milliohms (e.g., 0.02Ω for 5A peak) to several ohms (e.g., 1Ω for 100mA peak), enabling scalable current limiting. The IC senses up to 100mV across RSENSE, so resistor power rating and PCB trace resistance must be carefully considered.
LTC3803ES6-5#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
LTC3803ES6-5#TRMPBF FAQ
1.How can I place an order for LTC3803ES6-5#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3803ES6-5#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 LTC3803ES6-5#TRMPBF reliable?
The price and inventory of LTC3803ES6-5#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3803ES6-5#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3803ES6-5#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3803ES6-5#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3803ES6-5#TRMPBF?
LTC3803ES6-5#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3803ES6-5#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 LTC3803ES6-5#TRMPBF?
For technical support, including LTC3803ES6-5#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3803ES6-5#TRMPBF requirements.
6.How does Aetrix verify that LTC3803ES6-5#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3803ES6-5#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 LTC3803ES6-5#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3803ES6-5#TRMPBF?
All LTC3803ES6-5#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3803ES6-5#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 LTC3803ES6-5#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3803ES6-5#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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