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Analog Devices Inc. LTC3873ETS8-5#TRMPBF
- Part No.:
- LTC3873ETS8-5#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
LTC3873ETS8-5#TRMPBF.pdf
- Description:
- IC REG CTRLR MULT TOP TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,745
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Product details
Overview
LTC3873ETS8-5#TRMPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode DC/DC controller for boost, flyback, and SEPIC topologies, designed to drive external N-channel MOSFETs in high-input-voltage applications. It delivers ±1.5% output voltage accuracy, 200kHz fixed switching frequency, 4.1V VCC undervoltage lockout threshold, and operates from –40°C to 85°C in an 8-lead TSOT-23 package. It enables high-efficiency telecom housekeeping supplies with no external current-sense resistor required.
For engineers reviewing the LTC3873ETS8-5#TRMPBF datasheet, LTC3873ETS8-5#TRMPBF pinout, LTC3873ETS8-5#TRMPBF application, or LTC3873ETS8-5#TRMPBF equivalent, key selection criteria include its No RSENSE operation, internal 9.3V shunt regulator for high-VIN biasing, programmable current limit via IPRG pin, soft-start control via RUN/SS, and compatibility with high-voltage MOSFET gate drivers in isolated and non-isolated converters.
Technical Context
The LTC3873ETS8-5#TRMPBF implements current-mode control using an internal 1.2V reference and error amplifier with ITH as the compensation node. Its oscillator runs at a fixed 200kHz (±20%), and peak current limiting is set by IPRG pin state - yielding 95mV, 165mV, or 265mV thresholds depending on whether IPRG is tied to GND, floating, or VIN.
It features dual shutdown mechanisms: VCC UVLO (4.1V turn-on / 2.9V turn-off) and RUN/SS logic-level enable (0.7V threshold), plus internal soft-start (3.3ms ramp) and external soft-start capability. The NGATE driver supports rail-to-rail swing (0V to VIN) and drives N-MOSFET gates directly with 40ns rise/fall times into 3000pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 200kHz fixed - ensures predictable EMI profile and simplifies filter design in telecom and PoE power supplies. |
| Output Voltage Accuracy | ±1.5% - guarantees tight regulation across line, load, and temperature for stable downstream circuitry. |
| VCC UVLO Threshold | 4.1V rising / 2.9V falling - prevents MOSFET gate drive below safe VGS levels in automotive and industrial input ranges. |
| Quiescent Current | 300μA normal / 50μA shutdown - enables low-power standby modes in always-on telecom systems. |
| Max Duty Cycle | 78% typical - constrains transformer core saturation in flyback designs and limits max boost ratio (VOUT ≤ VIN / (1 − DMAX)). |
| Current Sense Threshold | 95–265mV (IPRG-selectable) - sets precise overcurrent protection without external sense resistor, reducing BOM count and conduction loss. |
| Shunt Regulator Voltage | 9.3V - allows direct high-VIN biasing (e.g., 36–75V telecom rails) via series resistor, eliminating auxiliary supply. |
Pinout & Package
Package: 8-lead TSOT-23 (ThinSOT™), 2.9mm × 1.6mm × 0.9mm, exposed pad not present (TS8 variant). Thermal resistance θJA = 230°C/W. RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IPRG (Pin 1) | Current limit select input | Configures peak current threshold: GND = 95mV, float = 165mV, VIN = 265mV - enables scalable OCP without resistor changes. |
| ITH (Pin 2) | Error amplifier output / compensation node | 0.7–1.9V range controls PWM duty cycle; connects to RC network for loop stability in boost/flyback/SEPIC. |
| VFB (Pin 3) | Feedback input | Monitors divided output voltage; regulates to 1.2V reference - supports remote sensing and adjustable VOUT via resistor divider. |
| GND (Pin 4) | Analog and power ground | Common reference for all internal circuits; must be low-impedance connection to minimize noise coupling. |
| NGATE (Pin 5) | N-MOSFET gate driver output | Drives external high-side N-channel switch; swings 0V to VIN - eliminates need for level-shifting in high-side configurations. |
| VCC (Pin 6) | Supply input with internal shunt regulator | Accepts 4.1–9V directly or >9V via series resistor; internal 9.3V clamp sinks up to 25mA - enables wide-input biasing. |
| RUN/SS (Pin 7) | Enable and soft-start control | Logic-level shutdown (≤0.7V); open = internal 3.3ms soft-start; capacitor to GND extends ramp - prevents inrush in hot-swap systems. |
| SW (Pin 8) | Switch node / current sense input | Connects to MOSFET drain and inductor; senses voltage drop across RDS(ON) or external resistor - enables No RSENSE operation. |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE current sensing | Eliminates external sense resistor - reduces conduction loss, board space, and cost in high-current boost/flyback converters. |
| Internal 9.3V shunt regulator | Allows direct biasing from high-VIN sources (e.g., 36–75V telecom) using only a series resistor - removes need for auxiliary LDO. |
| Programmable current limit | Three threshold options (95/165/265mV) selected by IPRG pin - enables flexible OCP tuning across load and MOSFET RDS(ON) variations. |
| 200kHz fixed-frequency operation | Stable switching frequency simplifies EMI filtering and avoids sub-harmonic instability - ideal for noise-sensitive telecom applications. |
| Low quiescent current (300μA) | Minimizes standby power in always-on systems such as PoE-powered devices and remote sensors. |
Applications
| Telecom Housekeeping Supply | PoE Powered Device (PD) Bias |
|---|---|
Use Scenario: Generating isolated 10V/100mA auxiliary rail from 36–75V telecom input for control logic and interface ICs. IC Role / Device Role / Timing Role: Primary-side flyback controller managing transformer energy transfer and output regulation without optocoupler feedback. Use Value: Enables compact, low-component-count isolated supply using No RSENSE sensing and internal 9.3V shunt - meets GR-1089 EMI requirements. | Use Scenario: Providing regulated 12V/2A output from 9–15V PoE midspan input in IP cameras or VoIP phones. IC Role / Device Role / Timing Role: SEPIC controller maintaining regulation during input voltage dips and surges common in PoE delivery. Use Value: Delivers stable output with ±1.5% accuracy and 200kHz switching - minimizes output ripple and simplifies compliance testing. |
| Automotive Infotainment Power | Negative Buck Converter |
Use Scenario: Stepping up 9–16V battery rail to 12V for display backlight or audio amplifiers in vehicles. IC Role / Device Role / Timing Role: Boost controller driving high-side N-MOSFET with NGATE output - avoids P-MOSFET inefficiency. Use Value: Supports cold-crank operation down to 4.1V VCC UVLO and maintains regulation across wide temperature range (–40°C to 85°C). | Use Scenario: Converting –10V to –15V input to regulated –5V/3A output for analog sensor interfaces or op-amp rails. IC Role / Device Role / Timing Role: Negative-to-negative buck controller using inverted topology with SW pin sensing polarity-reversed current. Use Value: Leverages same No RSENSE architecture and 200kHz frequency - achieves high efficiency without dedicated negative-input controllers. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3803ETS8-5#TRMPBF | Same 200kHz frequency and TSOT-23 package, but optimized exclusively for flyback; lacks SEPIC/boost support and IPRG current limit select. | Suitable only for isolated flyback where No RSENSE is needed; not usable in boost or SEPIC configurations. | Select LTC3873ETS8-5#TRMPBF when multi-topology flexibility (boost/flyback/SEPIC) or programmable current limit is required. |
| LTC3703-5IG#PBF | 100V input rating, SSOP-16 package, higher pin count; supports synchronous rectification and higher power levels. | Targeted at high-voltage industrial converters (>60V input); requires more PCB area and external MOSFET drivers. | Choose LTC3873ETS8-5#TRMPBF for space-constrained, medium-power telecom/PoE applications where 8-lead TSOT-23 footprint is critical. |
Compared with LTC3803ETS8-5#TRMPBF and LTC3703-5IG#PBF, the LTC3873ETS8-5#TRMPBF uniquely balances multi-topology support, ultra-compact packaging, and No RSENSE operation - making it optimal for cost- and size-sensitive isolated and non-isolated 1–5W converters.
Availability
LTC3873ETS8-5#TRMPBF is available at Aetrix Electronics and suitable for telecom power supplies, PoE-powered devices, and automotive infotainment systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LTC3873ETS8-5#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 technical and manufacturing continuity for all Linear power products. Linear pioneered high-performance analog ICs for precision power conversion.
The LTC3873-5 belongs to Linear's No RSENSE current-mode controller family, engineered specifically for high-efficiency, low-component-count DC/DC conversion in telecom, industrial, and automotive environments where board space and thermal constraints are critical.
FAQ
What is the maximum input voltage that LTC3873ETS8-5#TRMPBF can support?
The LTC3873ETS8-5#TRMPBF itself has an absolute maximum VCC rating of 9V, but its integrated 9.3V shunt regulator allows biasing from much higher input voltages - up to 75V - using a simple series resistor. External components (MOSFET, diode, transformer) determine the practical VIN limit, not the controller IC.
Does LTC3873ETS8-5#TRMPBF require an external current-sense resistor?
No. The LTC3873ETS8-5#TRMPBF supports No RSENSE operation by sensing voltage across the MOSFET's RDS(ON) via the SW pin. An external sense resistor is optional and used only when higher accuracy or isolation is needed - adding it increases conduction loss and BOM count.
What is the purpose of the IPRG pin on LTC3873ETS8-5#TRMPBF?
The IPRG pin on LTC3873ETS8-5#TRMPBF selects the peak current limit threshold: tying it to GND sets 95mV, leaving it floating sets 165mV, and connecting it to VIN sets 265mV. This enables precise overcurrent protection tuning without changing external components - critical for matching MOSFET RDS(ON) and load requirements.
Can LTC3873ETS8-5#TRMPBF be used in SEPIC topology?
Yes. The LTC3873ETS8-5#TRMPBF is explicitly designed for SEPIC, boost, and flyback topologies. Its current-mode architecture, SW pin sensing, and NGATE driver are fully compatible with SEPIC configurations - as confirmed in the datasheet's Typical Applications section (e.g., 9–15V to 12V SEPIC converter).
What is the operating temperature range for LTC3873ETS8-5#TRMPBF?
The LTC3873ETS8-5#TRMPBF is rated for –40°C to +85°C ambient temperature (E-grade). This range is validated per the datasheet's Absolute Maximum Ratings and Electrical Characteristics tables, ensuring reliable operation in industrial and automotive under-hood environments.
LTC3873ETS8-5#TRMPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- SOT-23-8 Thin, TSOT-23-8
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive, Isolation Capable
- Topology:
- Boost, Flyback, SEPIC
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4.1V ~ 60V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 78%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-8
LTC3873ETS8-5#TRMPBF FAQ
1.How can I place an order for LTC3873ETS8-5#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3873ETS8-5#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 LTC3873ETS8-5#TRMPBF reliable?
The price and inventory of LTC3873ETS8-5#TRMPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3873ETS8-5#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3873ETS8-5#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3873ETS8-5#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3873ETS8-5#TRMPBF?
LTC3873ETS8-5#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3873ETS8-5#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 LTC3873ETS8-5#TRMPBF?
For technical support, including LTC3873ETS8-5#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3873ETS8-5#TRMPBF requirements.
6.How does Aetrix verify that LTC3873ETS8-5#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3873ETS8-5#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 LTC3873ETS8-5#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3873ETS8-5#TRMPBF?
All LTC3873ETS8-5#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3873ETS8-5#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 LTC3873ETS8-5#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3873ETS8-5#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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