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Analog Devices Inc. LTC3873ETS8#TRPBF
- Part No.:
- LTC3873ETS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
LTC3873ETS8#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:3,449
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Product details
Overview
LTC3873ETS8#TRPBF from Analog Devices (formerly Linear Technology) is a constant-frequency current-mode DC/DC controller for boost, flyback, and SEPIC topologies, driving external N-channel MOSFETs in high-input-voltage telecom and automotive power supplies. It delivers ±1.5% output voltage accuracy, 200kHz fixed switching frequency, 300µA quiescent current, and supports RDS(ON) current sensing up to 60V on the SW node.
For engineers reviewing the LTC3873ETS8#TRPBF datasheet, LTC3873ETS8#TRPBF pinout, LTC3873ETS8#TRPBF application, or LTC3873ETS8#TRPBF equivalent, key selection criteria include its 8-lead ThinSOT™ package, programmable current limit via IPRG pin, internal 3.3ms soft-start, 9.3V shunt-regulated VCC supply, and operation across –40°C to 85°C junction temperature.
Technical Context
The LTC3873ETS8#TRPBF implements peak current-mode control with built-in slope compensation, enabling stable regulation across wide input/output ranges without external sense resistors. Its error amplifier outputs to the ITH pin (0.7V–1.9V range), directly setting the current comparator threshold and supporting fast line/load transient response.
VCC is internally regulated to 9.3V (±0.3V) with 25mA sink capability, allowing direct biasing from high-voltage inputs via a series resistor or from low-impedance 9V-or-less sources. The RUN/SS pin provides dual-function shutdown control and external soft-start timing via capacitor programming.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 200kHz fixed - enables predictable EMI filtering and compact magnetics design |
| Output Voltage Accuracy | ±1.5% - ensures tight regulation for sensitive telecom and industrial loads |
| Quiescent Current | 300µA normal / 55µA micropower start-up - minimizes standby loss in always-on systems |
| VCC Shunt Regulator | 9.3V ±0.3V - permits direct high-voltage biasing without external LDO |
| SW Node Max Voltage | 60V - supports RDS(ON) sensing in 48V telecom and 42V automotive applications |
| Current Sense Threshold | 110mV (IPRG = GND) to 295mV (IPRG = VIN) - enables precise, adjustable overcurrent protection |
| Undervoltage Lockout | 8.4V turn-on / 4.0V turn-off - provides 4.4V hysteresis for reliable startup under varying input conditions |
Pinout & Package
Package: 8-lead ThinSOT™ (TS8), 3mm × 1.75mm × 0.9mm profile, exposed pad not present (unlike DFN variant); RoHS-compliant, lead-free finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - IPRG | Current limit select input | Configures peak current threshold: GND = 110mV, float = 185mV, VIN = 295mV |
| 2 - ITH | Error amplifier output / compensation node | 0.7V–1.9V range sets current comparator trip point; used for loop compensation |
| 3 - VFB | Feedback input | Monitors divided output voltage; referenced to internal 1.2V bandgap (±1.5% accuracy) |
| 4 - GND | Analog and power ground | Common reference for all internal circuitry; requires low-impedance PCB connection |
| 5 - NGATE | N-channel MOSFET gate driver output | Drives external high-side switch; rail-to-rail swing from 0V to VIN |
| 6 - VCC | Supply input with internal shunt regulator | Accepts 9V max low-impedance source or higher voltage via series resistor (regulated to 9.3V) |
| 7 - RUN/SS | Shutdown enable / external soft-start | Pulled below 0.7V disables IC; capacitor to GND extends internal 3.3ms soft-start ramp |
| 8 - SW | Switch node / internal current sense input | Connects to MOSFET drain; senses RDS(ON) voltage or external sense resistor; rated to 60V |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE™ current sensing | Eliminates external sense resistor, reducing BOM cost, board space, and conduction losses |
| Programmable current limit | Three discrete thresholds via IPRG pin simplify overcurrent protection tuning across variants |
| Internal 3.3ms soft-start | Prevents inrush current and output overshoot; extended externally via RUN/SS capacitor |
| 9.3V internal shunt regulator | Enables single-resistor biasing from 36–72V telecom inputs without auxiliary supply |
| Constant 200kHz frequency | Ensures consistent EMI signature and simplifies filter design versus variable-frequency alternatives |
Applications
| Telecom Power Supply | Automotive 42V System |
|---|---|
Use Scenario: Non-isolated 5V/2A converter powered from 36–72V telecom rectified bus. IC Role / Device Role / Timing Role: Primary controller managing boost topology, current-mode regulation, and MOSFET gate drive timing. Use Value: Achieves >85% efficiency at full load using RDS(ON) sensing and eliminates need for external current-sense resistor. |
Use Scenario: 12V output supply for engine control units in 42V stop-start automotive systems. IC Role / Device Role / Timing Role: Flyback controller regulating isolated output while tolerating wide input transients (up to 60V). Use Value: 60V-rated SW pin and 4.4V UVLO hysteresis ensure robust operation during load-dump events. |
| Portable Equipment Power | Industrial SEPIC Converter |
Use Scenario: Step-up converter generating 12V from 9–15V battery input in portable test equipment. IC Role / Device Role / Timing Role: SEPIC controller providing non-inverting buck-boost regulation with continuous input/output current. Use Value: Fixed 200kHz frequency and ±1.5% reference accuracy maintain stable output under dynamic load steps. |
Use Scenario: Industrial sensor interface requiring 12V output from fluctuating 9–15V input with inherent input-output isolation. IC Role / Device Role / Timing Role: Constant-frequency SEPIC controller with internal slope compensation for stability at duty cycles >50%. Use Value: IPRG-selectable current limit allows optimization for transformer saturation margin and peak current stress. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3873EDDB#TRPBF | Same die, 8-lead 3mm × 2mm DFN package with exposed thermal pad (θJA = 76°C/W vs TS8's 230°C/W) | Better thermal performance required for >1.5A continuous output or high ambient temperatures | Select when PCB layout allows DFN footprint and thermal pad soldering; not pin-compatible with TS8 |
| LTC3872ETS8#TRPBF | Different architecture: no RDS(ON) sensing, requires external sense resistor; 300kHz frequency; lower IQ (120µA) | Suitable only where RDS(ON) sensing is unnecessary and higher frequency is preferred | Choose only if RDS(ON) sensing is undesirable and 300kHz switching is required; not functionally interchangeable |
Compared with LTC3873EDDB#TRPBF, the LTC3873ETS8#TRPBF offers lower thermal resistance in compact space-constrained designs but requires more careful layout for heat dissipation; compared with LTC3872ETS8#TRPBF, it provides superior efficiency and reduced component count via No RSENSE™ operation but operates at half the switching frequency.
Availability
LTC3873ETS8#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, 42V automotive systems, and portable electronic equipment requiring stable component supply, long-term lifecycle support, and guaranteed RoHS-compliant sourcing.
Supply support for LTC3873ETS8#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 high-performance analog and power management portfolio with rigorous reliability testing and automotive-grade qualification programs.
The LTC3873ETS8#TRPBF belongs to Linear's No RSENSE™ current-mode controller family, designed specifically for high-efficiency, low-component-count DC/DC conversion in telecom, industrial, and automotive power systems.
FAQ
What is the maximum input voltage the LTC3873ETS8#TRPBF can handle?
The LTC3873ETS8#TRPBF itself does not have a maximum input voltage rating-its VCC pin is internally shunt-regulated to 9.3V, allowing biasing from high-voltage sources (e.g., 36–72V telecom buses) via a series resistor. The SW pin is rated to 60V, defining the practical upper limit for RDS(ON) sensing or external sense resistor placement in boost/flyback/SEPIC configurations.
Does the LTC3873ETS8#TRPBF require an external current sense resistor?
No-the LTC3873ETS8#TRPBF implements Linear's No RSENSE™ technology, enabling current sensing via the RDS(ON) of the external N-channel MOSFET. An external sense resistor is optional and only needed if RDS(ON) sensing is impractical; the SW pin supports either configuration with identical pin connections.
What is the purpose of the IPRG pin on the LTC3873ETS8#TRPBF?
The IPRG pin on the LTC3873ETS8#TRPBF selects one of three peak current limit thresholds: 110mV (IPRG = GND), 185mV (IPRG = floating), or 295mV (IPRG = VIN). This allows designers to tailor overcurrent protection to specific MOSFET RDS(ON), transformer turns ratio, and load requirements without changing feedback components.
Can the LTC3873ETS8#TRPBF operate in discontinuous conduction mode (DCM)?
Yes-the LTC3873ETS8#TRPBF maintains constant 200kHz frequency even under very light loads by cycle-skipping when the ITH pin voltage approaches 0.85V. This preserves low output ripple and audible noise while achieving high light-load efficiency, unlike variable-frequency controllers that shift EMI spectra unpredictably.
What is the recommended soft-start duration for the LTC3873ETS8#TRPBF?
The LTC3873ETS8#TRPBF features a default internal soft-start of 3.3ms, sufficient for most telecom and industrial applications. To extend soft-start, connect a capacitor from RUN/SS to GND; a 3µA internal current charges it, yielding ~1ms per 330nF. For example, a 100nF capacitor extends soft-start to ~330ms, preventing inrush in high-capacitance output stages.
LTC3873ETS8#TRPBF 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):
- 8.4V ~ 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#TRPBF FAQ
1.How can I place an order for LTC3873ETS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3873ETS8#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 LTC3873ETS8#TRPBF reliable?
The price and inventory of LTC3873ETS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3873ETS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3873ETS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3873ETS8#TRPBF transactions.
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4.How is shipping managed for LTC3873ETS8#TRPBF?
LTC3873ETS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3873ETS8#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 LTC3873ETS8#TRPBF?
For technical support, including LTC3873ETS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3873ETS8#TRPBF requirements.
6.How does Aetrix verify that LTC3873ETS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3873ETS8#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 LTC3873ETS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3873ETS8#TRPBF?
All LTC3873ETS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3873ETS8#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 LTC3873ETS8#TRPBF part is unused and in its original packaging.
Return procedure for LTC3873ETS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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