My Inquiry
My Account
Analog Devices Inc. LTC3873ETS8#TRMPBF
- Part No.:
- LTC3873ETS8#TRMPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
LTC3873ETS8#TRMPBF.pdf
- Description:
- IC REG CTRLR MULT TOP TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:157
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3873ETS8#TRMPBF 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#TRMPBF datasheet, LTC3873ETS8#TRMPBF pinout, LTC3873ETS8#TRMPBF application, or LTC3873ETS8#TRMPBF equivalent, key selection considerations include its 8-lead TSOT-23 package, programmable current limit via IPRG pin, internal 3.3ms soft-start, 9.3V shunt-regulated VCC supply, and compatibility with high-voltage input ranges (36V–72V) in nonisolated telecom converters.
Technical Context
The LTC3873ETS8#TRMPBF implements peak current-mode control with built-in slope compensation and a 200kHz oscillator, enabling stable regulation across wide line/load transients. Its error amplifier outputs to the ITH pin (0.7V–1.9V range), which sets the current comparator threshold and interfaces with external compensation networks.
Voltage regulation is achieved by comparing the feedback signal at VFB to an internal 1.2V reference; output voltage is set via resistor divider (VOUT = 1.2V × (1 + R2/R1)). The device supports dual powering schemes: direct low-impedance DC supply ≤9V or high-voltage bias through a resistor into the 9.3V VCC shunt regulator.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Topology Support | Boost, flyback, SEPIC - enables flexible converter design without topology-specific ICs |
| Switching Frequency | 200kHz fixed - ensures predictable EMI profile and simplifies filter design |
| Output Voltage Accuracy | ±1.5% - guarantees tight regulation for sensitive loads like telecom line cards |
| Quiescent Current | 300µA normal / 55µA micropower start-up - extends battery life in portable equipment |
| VCC Shunt Regulator | 9.3V ±0.3V - allows direct high-voltage biasing (e.g., 36–72V telecom rails) with minimal external components |
| SW Node Max Voltage | 60V - supports RDS(ON) sensing in high-output-voltage boost/flyback designs |
| Current Sense Options | RDS(ON) or external resistor - eliminates sense resistor losses and improves efficiency |
Pinout & Package
Package: 8-lead TSOT-23 (ThinSOT™), 2.9mm × 1.75mm × 1.0mm profile, exposed pad not present (unlike DFN variant). Pin 1 marked with dot; pin 1 = IPRG, pin 4 = GND, pin 5 = NGATE, pin 6 = VCC, pin 7 = RUN/SS, pin 8 = SW.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IPRG (Pin 1) | Current limit select input | Configures peak current threshold to 95mV (GND), 185mV (float), or 295mV (VIN) - enables precise overcurrent protection tuning |
| ITH (Pin 2) | Error amplifier output / compensation node | 0.7V–1.9V voltage range controls PWM duty cycle; connects to RC network for loop stability |
| VFB (Pin 3) | Feedback input | Compares divided output voltage to 1.2V internal reference; 25nA input bias minimizes divider current loss |
| GND (Pin 4) | Power and signal ground reference | Common return for VCC, ITH, VFB, RUN/SS; must be low-impedance connection to minimize noise coupling |
| NGATE (Pin 5) | N-channel MOSFET gate driver output | Drives external FET gate with rail-to-rail swing (0V to VIN); 40ns rise/fall time supports fast switching |
| VCC (Pin 6) | Supply input with internal shunt regulator | Accepts 9V max low-impedance supply or high-voltage bias; internal 9.3V clamp sinks up to 25mA |
| RUN/SS (Pin 7) | Shutdown enable / soft-start timing | Pulled low (<0.7V) disables operation; open-circuit enables 3.3ms internal soft-start; external capacitor extends ramp |
| SW (Pin 8) | Switch node / current sense input | Connects to MOSFET drain and inductor; senses RDS(ON) voltage or external resistor; rated to 60V |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE current sensing | Eliminates power loss and board space of external sense resistor; leverages MOSFET RDS(ON) for current measurement |
| Programmable current limit | Three thresholds (95/185/295mV) selected via IPRG pin - adapts protection level to MOSFET and load requirements |
| Internal soft-start (3.3ms) | Prevents inrush current and output overshoot during power-up; extended via external capacitor on RUN/SS |
| High-voltage VCC bias capability | 9.3V internal shunt regulator enables direct connection to 36–72V telecom inputs using only a series resistor |
| Current-mode control | Provides inherent cycle-by-cycle current limiting and superior line/load transient response vs voltage-mode controllers |
Applications
| Telecom Power Supply | Automotive 42V System |
|---|---|
Use Scenario: Nonisolated 5V/2A DC/DC converter powered from 36–72V telecom central office supply. IC Role / Device Role / Timing Role: Primary controller managing boost topology, regulating output via VFB feedback, and driving external MOSFET through NGATE. Use Value: Achieves >85% efficiency at full load with no external current sense resistor, reducing BOM cost and thermal footprint. | Use Scenario: 12V auxiliary supply in 42V automotive systems (e.g., engine control units). IC Role / Device Role / Timing Role: Flyback controller providing isolated 12V output; uses transformer bias winding for self-powered VCC. Use Value: Operates reliably across –40°C to +85°C ambient; UVLO hysteresis (4.0V–8.4V) accommodates cold-crank voltage dips. |
| Portable Equipment Power | Industrial SEPIC Converter |
Use Scenario: Step-up converter generating 12V from 9–15V Li-ion battery pack in handheld test equipment. IC Role / Device Role / Timing Role: SEPIC controller maintaining regulation during battery discharge; ITH compensation stabilizes loop under variable input. Use Value: 55µA micropower start-up extends shelf life; low quiescent current preserves runtime in standby modes. | Use Scenario: Industrial 12V/2A supply tolerant of input reversal or wide-range 9–15V inputs (e.g., factory automation sensors). IC Role / Device Role / Timing Role: SEPIC topology controller ensuring continuous conduction mode; RDS(ON) sensing avoids failure-prone sense resistors in harsh environments. Use Value: 70–84% maximum duty cycle prevents core saturation; robust 60V SW rating handles inductive kickback in noisy settings. |
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 GND pad; θJA = 76°C/W vs 230°C/W for TSOT-23 | Better thermal performance in high-power density layouts; requires PCB soldering of exposed pad | Select for >1.5A output or thermally constrained PCBs; not pin-compatible due to different footprint |
| LTC3872ETS8#TRMPBF | Different current-sense architecture (no IPRG pin); fixed 110mV current limit; lacks RDS(ON) sensing option | Simpler implementation where adjustable current limit is unnecessary; lower cost for fixed-threshold designs | Choose when design does not require programmable OCP or 60V SW rating; shares same TSOT-23 footprint but different pinout |
Compared with LTC3873EDDB#TRPBF, the LTC3873ETS8#TRMPBF offers higher thermal resistance but smaller board area; compared with LTC3872ETS8#TRMPBF, it adds RDS(ON) sensing and IPRG-based current limit flexibility at the cost of slightly higher complexity.
Availability
LTC3873ETS8#TRMPBF is available at Aetrix Electronics and suitable for telecom power supplies, 42V automotive systems, and portable electronic equipment requiring stable component supply across industrial temperature ranges (–40°C to +85°C).
Supply support for LTC3873ETS8#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 high-performance analog and power management portfolio.
The LTC3873ETS8#TRMPBF belongs to Linear's high-voltage current-mode controller product line, designed specifically for efficient, compact DC/DC conversion in telecom, automotive, and industrial applications where input voltage exceeds standard IC supply limits.
FAQ
What is the maximum input voltage the LTC3873ETS8#TRMPBF can handle?
The LTC3873ETS8#TRMPBF itself has an absolute maximum SW node voltage of 60V and VCC supply limit of 9V. However, because it supports high-side RDS(ON) current sensing and can be biased via a resistor from inputs up to 72V (using its internal 9.3V shunt regulator), the effective system input voltage is limited only by external MOSFET and transformer ratings - demonstrated in typical applications with 36V–72V telecom inputs. The LTC3873ETS8#TRMPBF does not regulate input voltage directly.
Does the LTC3873ETS8#TRMPBF require an external current sense resistor?
No, the LTC3873ETS8#TRMPBF supports No RSENSE operation by measuring voltage drop across the external N-channel MOSFET's RDS(ON), eliminating the need for a discrete sense resistor. An external resistor may be used instead if higher accuracy or isolation is required, but it is optional. This feature reduces power loss and component count in the LTC3873ETS8#TRMPBF design.
What is the purpose of the IPRG pin on the LTC3873ETS8#TRMPBF?
The IPRG pin on the LTC3873ETS8#TRMPBF selects the peak current limit threshold: 95mV when tied to GND, 185mV when left floating, and 295mV when connected to VIN. This allows designers to match the current limit to the chosen MOSFET's RDS(ON) and expected load, enabling precise overcurrent protection without recalculating sense resistor values. The LTC3873ETS8#TRMPBF uses this setting to adjust the current comparator trip point dynamically.
Can the LTC3873ETS8#TRMPBF be used in flyback configurations with primary-side regulation?
Yes, the LTC3873ETS8#TRMPBF is explicitly validated for flyback operation in its datasheet, including primary-side regulation using optocoupler feedback (e.g., LT4430-based compensation). Its current-mode architecture provides inherent stability, and the RUN/SS pin supports controlled start-up sequences critical in isolated topologies. The LTC3873ETS8#TRMPBF's 60V SW rating and programmable current limit make it suitable for discontinuous and continuous conduction mode flyback designs.
What is the function of the RUN/SS pin on the LTC3873ETS8#TRMPBF?
The RUN/SS pin on the LTC3873ETS8#TRMPBF serves dual functions: applying <0.7V forces shutdown (reducing supply current to 55µA), while leaving it open enables internal 3.3ms soft-start. An external capacitor from RUN/SS to GND extends soft-start duration linearly (3µA charging current). This pin also provides logic-level enable/disable control, making the LTC3873ETS8#TRMPBF suitable for power sequencing in multi-rail systems.
LTC3873ETS8#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):
- 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#TRMPBF FAQ
1.How can I place an order for LTC3873ETS8#TRMPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3873ETS8#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#TRMPBF reliable?
The price and inventory of LTC3873ETS8#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#TRMPBF is usually 5 days.
3.What payment methods are accepted for LTC3873ETS8#TRMPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3873ETS8#TRMPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3873ETS8#TRMPBF?
LTC3873ETS8#TRMPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3873ETS8#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#TRMPBF?
For technical support, including LTC3873ETS8#TRMPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3873ETS8#TRMPBF requirements.
6.How does Aetrix verify that LTC3873ETS8#TRMPBF is sourced from the original manufacturer or authorized distributors?
All LTC3873ETS8#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#TRMPBF meets industry standards.
7.What is the process for return or replacement of LTC3873ETS8#TRMPBF?
All LTC3873ETS8#TRMPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3873ETS8#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#TRMPBF part is unused and in its original packaging.
Return procedure for LTC3873ETS8#TRMPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3873ETS8#TRMPBF Tags
-
UCC28C45DR
Texas Instruments
-
UCC28C40DR
Texas Instruments
-
UCC28C43DR
Texas Instruments
-
ZXSC410E6TA
Diodes Incorporated
-
LM3524DMX/NOPB
Texas Instruments
-
LM3489MMX/NOPB
Texas Instruments
-
MIC2102YML-TR
Microchip Technology
-
LM5148RGYR
Texas Instruments
-
TL598CDR
Texas Instruments
-
LM5155DSSR
Texas Instruments
-
LM25085MYX/NOPB
Texas Instruments
-
UCC2813DTR-0
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
