My Inquiry
My Account
Analog Devices Inc. LTC3873ITS8-5#TRPBF
- Part No.:
- LTC3873ITS8-5#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- SOT-23-8 Thin, TSOT-23-8
- Datasheet:
-
LTC3873ITS8-5#TRPBF.pdf
- Description:
- IC REG CTRLR MULT TOP TSOT23-8
- Quantity:
- Payment:
- Shipping:
Inventory:1,832
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3873ITS8-5#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, 4.1V VCC undervoltage lockout threshold, and operates across –40°C to +125°C with 300μA quiescent current.
For engineers reviewing the LTC3873ITS8-5#TRPBF datasheet, LTC3873ITS8-5#TRPBF pinout, LTC3873ITS8-5#TRPBF application, or LTC3873ITS8-5#TRPBF equivalent, key selection criteria include its No RSENSE current sensing capability, internal 9.3V shunt regulator for high-VIN biasing, programmable current limit via IPRG pin, soft-start control via RUN/SS, and compatibility with wide input/output voltage ranges defined by external components.
Technical Context
The LTC3873ITS8-5#TRPBF implements peak current-mode control with built-in slope compensation to prevent subharmonic oscillation at duty cycles >50%. Its error amplifier outputs a voltage at the ITH pin that sets the current comparator threshold, enabling tight regulation under line and load transients.
It supports dual powering schemes: direct low-impedance supply ≤9V to VCC, or high-VIN resistor-fed operation using the internal 9.3V shunt regulator. The RUN/SS pin provides both shutdown control and soft-start timing-internal default is 3.3ms, extendable with external capacitor.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Oscillator Frequency | 200kHz fixed - enables predictable EMI filtering and consistent magnetics design |
| Output Voltage Accuracy | ±1.5% - ensures stable regulation across temperature and line/load variations |
| VCC UVLO Threshold | Rising: 4.1V - prevents MOSFET gate drive below safe VGS level in logic-level applications |
| Quiescent Current | 300μA normal / 50μA shutdown - minimizes standby power loss in always-on systems |
| Max Duty Cycle | 78% typical - limits transformer core saturation in flyback and constrains max boost ratio |
| Current Sense Options | IPRG-selectable thresholds (95–295mV) - allows RDS(ON) sensing or discrete resistor use without added components |
| Operating Temp Range | –40°C to +125°C - qualified for under-hood automotive and industrial telecom environments |
Pinout & Package
Package: 8-lead TSOT-23 (ThinSOT), 1mm profile, lead-free, RoHS-compliant. Exposed pad not present in TS8 package.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| IPRG (Pin 1) | Current limit select input | Configures peak sense threshold: GND = 95mV, float = 185mV, VIN = 295mV |
| ITH (Pin 2) | Error amplifier output / compensation node | Carries loop compensation signal; nominal range 0.7V–1.9V; controls current comparator trip point |
| VFB (Pin 3) | Feedback input | Compares divided output voltage to 1.2V reference; 25nA input bias enables high-impedance dividers |
| GND (Pin 4) | Analog and power ground | Common return for feedback, error amp, and internal regulators; must be low-impedance |
| NGATE (Pin 5) | N-MOSFET gate driver output | Drives external high-side N-channel switch; rail-to-rail swing from 0V to VIN |
| VCC (Pin 6) | Supply input with internal shunt regulator | Accepts 4.1V–9V directly or higher VIN via series resistor; clamped at ~9.3V/25mA max |
| RUN/SS (Pin 7) | Shutdown enable & soft-start control | Below 0.7V disables IC; open-circuit enables 3.3ms internal soft-start; external cap extends ramp |
| SW (Pin 8) | Switch node / current sense input | Connects to MOSFET drain and inductor; senses voltage drop for No RSENSE operation up to 60V |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE current sensing | Eliminates sense resistor losses and board space; uses MOSFET RDS(ON) with selectable thresholds |
| Internal 9.3V shunt regulator | Enables direct high-VIN biasing (e.g., 36–75V telecom rails) without external LDO or zener |
| Programmable current limit | Three discrete thresholds via IPRG pin simplify overcurrent protection tuning across designs |
| Constant 200kHz frequency | Ensures repeatable EMI behavior and simplifies filter design versus variable-frequency alternatives |
| Low-profile TSOT-23 package | 8-lead 3×3mm footprint with 1mm height supports dense PCB layouts in space-constrained modules |
Applications
| Telecom Housekeeping Supply | Automotive Infotainment Rail |
|---|---|
Use Scenario: Generating isolated 10V/100mA bias for FPGA or MCU in 36–75V telecom chassis. IC Role / Device Role / Timing Role: Flyback controller managing primary-side regulation without optocoupler or secondary-side feedback. Use Value: Leverages No RSENSE sensing and internal shunt regulator to eliminate external bias supply, reducing BOM count by ≥3 components. | Use Scenario: Stepping 9–16V battery input to stable 12V for display backlight or audio amplifier in vehicle head units. IC Role / Device Role / Timing Role: Boost controller operating at fixed 200kHz to avoid AM band interference while supporting cold-crank down to 4.1V VCC UVLO. Use Value: 300μA quiescent current and –40°C to +125°C rating ensure reliable start-up and low parasitic drain during vehicle off-state. |
| Industrial PoE PD Interface | Isolated Negative Buck Converter |
Use Scenario: Providing auxiliary 5V/2A rail from IEEE 802.3af/at PSE input in powered device equipment. IC Role / Device Role / Timing Role: SEPIC controller handling wide input (36–57V) and maintaining regulation during PSE negotiation transients. Use Value: Adjustable current limit and 200kHz frequency allow optimized magnetics for compact, thermally efficient PoE adapter designs. | Use Scenario: Generating –5V/3A from –10V to –15V input in legacy instrumentation requiring negative rails. IC Role / Device Role / Timing Role: Negative-buck (inverting) controller using standard boost topology with polarity-reversed inductor and diode. Use Value: Internal 1.2V reference and ±1.5% accuracy ensure precise negative output regulation without trimming resistors. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost/flyback/SEPIC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3803ITS8-5#TRPBF | 200kHz fixed frequency, same TSOT-23 package, but lacks No RSENSE and internal shunt regulator; requires external sense resistor and bias supply | Better suited for cost-sensitive, lower-input-voltage (<24V) applications where RDS(ON) sensing isn't needed | Select when minimizing component count is less critical than absolute lowest BOM cost and input voltage stays below 24V |
| LTC3872EMS8E-5#TRPBF | Same No RSENSE architecture and 200kHz frequency, but in MSOP-8 package with enhanced light-load efficiency and 2.5V startup capability | Preferred for ultra-low-IQ battery-powered systems needing <50μA shutdown current and wider VIN range | Select when operating from weak sources (e.g., energy harvesters) or requiring extended low-VIN functionality below 4.1V |
Compared with LTC3873ITS8-5#TRPBF, LTC3803ITS8-5#TRPBF trades No RSENSE and shunt regulation for lower unit cost, while LTC3872EMS8E-5#TRPBF adds ultra-low-IQ operation and lower startup voltage at the expense of larger MSOP-8 footprint.
Availability
LTC3873ITS8-5#TRPBF is available at Aetrix Electronics and suitable for telecom power supplies, automotive infotainment systems, and PoE-powered devices requiring stable component supply across extended temperature and high-reliability production cycles.
Supply support for LTC3873ITS8-5#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 full product support, documentation, and manufacturing continuity for all Linear DC/DC controllers.
The LTC3873 family was designed specifically for high-efficiency, high-voltage boost/flyback/SEPIC converters in space- and thermal-constrained telecom and automotive applications, emphasizing simplicity, reliability, and No RSENSE integration.
FAQ
What is the maximum input voltage the LTC3873ITS8-5#TRPBF can handle?
The LTC3873ITS8-5#TRPBF itself has an absolute maximum SW pin rating of 60V and VCC rating of 9V. However, because it drives external components, the effective input voltage is limited only by the ratings of the external MOSFET, diode, and transformer. Its internal 9.3V shunt regulator enables direct biasing from inputs up to ~100V using a series resistor, making it suitable for 36–75V telecom and 12–48V industrial applications.
Does the LTC3873ITS8-5#TRPBF require an external current sense resistor?
No - the LTC3873ITS8-5#TRPBF implements No RSENSE current sensing, allowing direct use of the MOSFET's RDS(ON) for current limiting. An external sense resistor is optional and only needed if higher precision or isolation is required. When used, the SW pin serves as the sense input node, eliminating the need for additional current-sense amplifiers.
How does the RUN/SS pin function on the LTC3873ITS8-5#TRPBF?
The RUN/SS pin on the LTC3873ITS8-5#TRPBF serves dual roles: applying <0.7V forces shutdown (reducing IQ to 50μA), while leaving it open enables internal 3.3ms soft-start. An external capacitor from RUN/SS to GND extends soft-start time linearly (3μA charge current), and driving it with ≥2.75V logic ensures full ITH range. This pin replaces separate enable and soft-start circuits in discrete implementations.
What package type and thermal performance does the LTC3873ITS8-5#TRPBF use?
The LTC3873ITS8-5#TRPBF uses an 8-lead TSOT-23 (ThinSOT) package with 1mm profile and no exposed pad. Its thermal resistance is θJA = 230°C/W. For high-power designs, layout best practices include maximizing copper area under the IC and routing NGATE/SW traces away from sensitive analog nodes to manage self-heating within the –40°C to +125°C junction limit.
Can the LTC3873ITS8-5#TRPBF be used in flyback configurations without an optocoupler?
Yes - the LTC3873ITS8-5#TRPBF supports primary-side regulation in flyback topologies using reflected voltage sensing on the auxiliary winding. Combined with its accurate 1.2V reference and ±1.5% output voltage tolerance, this eliminates the need for optocouplers and TL431 references in many isolated housekeeping supplies, as demonstrated in the 1W Telecom Housekeeping reference design.
LTC3873ITS8-5#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):
- 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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- TSOT-23-8
LTC3873ITS8-5#TRPBF FAQ
1.How can I place an order for LTC3873ITS8-5#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3873ITS8-5#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 LTC3873ITS8-5#TRPBF reliable?
The price and inventory of LTC3873ITS8-5#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3873ITS8-5#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3873ITS8-5#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3873ITS8-5#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3873ITS8-5#TRPBF?
LTC3873ITS8-5#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3873ITS8-5#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 LTC3873ITS8-5#TRPBF?
For technical support, including LTC3873ITS8-5#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3873ITS8-5#TRPBF requirements.
6.How does Aetrix verify that LTC3873ITS8-5#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3873ITS8-5#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 LTC3873ITS8-5#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3873ITS8-5#TRPBF?
All LTC3873ITS8-5#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3873ITS8-5#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 LTC3873ITS8-5#TRPBF part is unused and in its original packaging.
Return procedure for LTC3873ITS8-5#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3873ITS8-5#TRPBF 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…
