My Inquiry
My Account
Analog Devices Inc. LTC3879IUD#PBF
- Part No.:
- LTC3879IUD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LTC3879IUD#PBF.pdf
- Description:
- IC REG CTRLR BUCK 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,970
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
LTC3879IUD#PBF from Analog Devices (formerly Linear Technology) is a synchronous step-down switching regulator controller optimized for high-frequency operation and fast transient response in wide-input-voltage DC/DC systems. It features valley current mode control without external sense resistors, ±1% 0.6V reference, 43ns minimum on-time, and dual N-channel MOSFET drive - enabling high step-down ratios in distributed power supplies for communications infrastructure.
For engineers reviewing the LTC3879IUD#PBF datasheet, LTC3879IUD#PBF pinout, LTC3879IUD#PBF application, or LTC3879IUD#PBF equivalent, key selection criteria include its 4V–38V input range, programmable current limit with foldback, forced continuous/discontinuous mode control via MODE pin, and compatibility with low-ESR ceramic output capacitors.
Technical Context
The LTC3879IUD#PBF implements constant-on-time valley current mode control, eliminating need for slope compensation or external RSENSE. Its one-shot timer sets tON proportional to ideal duty cycle, enabling pseudo-fixed frequency operation across input voltage variations while maintaining line stability.
It supports pre-biased soft-start, independent RUN/SS control, output overvoltage protection, and adjustable switching frequency via ION pin resistor. The VRNG pin scales valley current sense threshold from 22mV to 98mV, allowing optimization for different MOSFET RDS(ON) values and thermal margins.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports wide industrial/comms input rails including 5V, 12V, 24V, and 28V systems |
| Feedback Reference | ±1% at 0.6V - enables precise regulation of outputs as low as 0.6V with minimal drift over temperature |
| Min On-Time | 43ns - allows stable operation at high step-down ratios (e.g., 24V→1.2V @ 400kHz) |
| Switching Frequency | Programmable via ION pin resistor - compensates for VIN variation to maintain stable frequency |
| Current Sense Threshold | Adjustable 22mV–98mV via VRNG pin - eliminates need for discrete sense resistor while supporting diverse MOSFET RDS(ON) |
| Output Protection | Programmable current limit with foldback + output overvoltage protection - prevents damage during short-circuit or fault conditions |
| Package | 16-pin 3mm × 3mm QFN - thermally enhanced with exposed SGND pad for efficient heat dissipation |
Pinout & Package
Package: 16-lead (3mm × 3mm) plastic QFN with exposed thermal pad (Pin 17 = SGND). Requires soldering of exposed pad to PCB ground plane for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| TRACK/SS (1) | Soft-start & tracking input | Internal 1μA pull-up; capacitor sets ramp time or resistor divider enables rail tracking - ensures controlled start-up into pre-biased loads |
| PGOOD (2) | Power-good open-drain output | Asserts low when VOUT deviates >±10% from regulation - provides system-level power sequencing and fault signaling |
| VRNG (3) | VDS sense range select | Sets max valley current sense threshold (22–98mV); tied to SGND → 30mV typical, to INTVCC → 75mV typical |
| MODE (4) | Continuous/discontinuous mode control | Tied to SGND → forces CCM; tied to INTVCC → enables DCM at light load for higher efficiency |
| ITH (5) | Error amplifier output / current limit setpoint | Voltage (0–2.4V) sets valley current comparator threshold - EA adjusts ITH to regulate VOUT |
| SGND (6) | Signal ground reference | Reference for all small-signal pins; must be connected to PGND at single point to avoid noise coupling |
| ION (7) | On-time current input | Resistor from VIN sets tON and thus switching frequency - enables VIN-compensated pseudo-fixed frequency |
| VFB (8) | Feedback input | Compares output voltage (via resistor divider) to 0.6V reference - primary regulation node for closed-loop control |
| RUN (9) | Enable/disable control | <0.7V → micropower shutdown (18μA); 0.7–1.5V → bias enabled, no switching; >1.5V → full operation |
| VIN (10) | Main input supply | 4V–38V input rail; requires RC filter to PGND for noise immunity in noisy environments |
| INTVCC (11) | Internal 5.3V regulator output | Powers gate drivers and internal circuitry; requires ≥1μF X5R/X7R ceramic decoupling to PGND |
| BG (12) | Bottom gate driver output | Drives bottom N-MOSFET gate between PGND and INTVCC - 0.7Ω pull-down, 2.5Ω pull-up |
| PGND (13) | Power ground return | Low-impedance return for bottom MOSFET source, CIN, and CINTVCC - must be placed adjacent to MOSFET source |
| SW (14) | Switch node | Connects to source of top MOSFET and (–) terminal of bootstrap capacitor - swings from ~–0.3V to VIN |
| TG (15) | Top gate driver output | Drives top N-MOSFET gate between SW and BOOST - 1.2Ω pull-down, 2.5Ω pull-up |
| BOOST (16) | Bootstrap supply | Connects to (+) terminal of bootstrap capacitor - floats with SW to enable high-side N-MOSFET drive |
Key Features
| Feature | Design Value |
|---|---|
| No RSENSE valley current sensing | Uses bottom MOSFET RDS(ON) for current sensing - eliminates power loss and board space of discrete sense resistor |
| Stable with ceramic output capacitors | Designed for low-ESR ceramic COUT - avoids instability issues common in controllers requiring electrolytic or tantalum caps |
| Pre-biased output start-up | Supports smooth regulation ramp even when output is already biased - critical for hot-swap and multi-rail sequencing |
| Adjustable soft-start or tracking | TRACK/SS pin accepts external voltage reference - enables synchronized start-up of multiple rails (e.g., 1.2V tracking 1.8V) |
| Forced continuous mode control | MODE pin disables discontinuous mode - eliminates audible noise and EMI variability in sensitive applications |
Applications
| Telecom Base Station Power | Industrial PLC CPU Core Supply |
|---|---|
Use Scenario: Point-of-load conversion from 24V or 48V intermediate bus to 1.2V/15A for FPGA or ASIC core logic. IC Role / Device Role / Timing Role: Primary step-down controller managing high-current, low-voltage rail with fast load transients from digital logic switching. Use Value: 43ns min on-time enables stable 24V→1.2V conversion at 400kHz; valley current mode delivers <50μs recovery from 0→10A load steps. | Use Scenario: Reliable 5V→3.3V or 12V→3.3V conversion for microcontroller and I/O power in harsh industrial environments. IC Role / Device Role / Timing Role: Synchronous buck controller providing regulated 3.3V with overvoltage and current-limit protection for long-life embedded systems. Use Value: Wide 4V–38V input range accommodates brownout and surge conditions; ±1% reference ensures consistent MCU timing across temperature. |
| Networking Switch ASIC Supply | Medical Imaging Data Acquisition |
Use Scenario: High-efficiency 12V→0.85V supply for multi-core network processor with strict ripple and transient requirements. IC Role / Device Role / Timing Role: Fast-transient controller delivering sub-1% output deviation during burst traffic-induced load jumps. Use Value: Programmable VRNG pin allows tuning of current sense threshold to match low-RDS(ON) MOSFETs, minimizing conduction loss at 30A+ loads. | Use Scenario: Low-noise, fault-tolerant 24V→5V/3.3V conversion for analog front-end and ADC reference supplies in portable imaging devices. IC Role / Device Role / Timing Role: Controller with PGOOD monitoring and programmable current limit - ensures clean power delivery and safe shutdown during sensor faults. Use Value: Discontinuous mode (via MODE pin) reduces light-load quiescent current to <35μA, extending battery life without sacrificing peak performance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar synchronous step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3892IUFD#PBF | Dual-output controller; includes second channel, higher IQ (250μA), wider temp range (–40°C to 125°C) | Required for dual-rail systems (e.g., core + I/O); not drop-in due to extra pins and control logic | Select when needing two independent synchronous buck channels or extended temperature operation |
| MP2918GL-Z | Fixed 600kHz frequency; no VRNG pin; lower max VIN (36V); lacks pre-bias start-up support | Suitable for cost-sensitive, fixed-frequency designs where MOSFET RDS(ON) is tightly controlled and input never drops below 5V | Choose for simpler BOM and layout where advanced features like tracking or wide-VIN margin are unnecessary |
Compared with LTC3892IUFD#PBF and MP2918GL-Z, the LTC3879IUD#PBF offers superior flexibility in frequency programming, valley current threshold adjustment, and pre-biased start-up - making it optimal for high-performance, single-rail telecom and computing power supplies where transient response and design margin are critical.
Availability
LTC3879IUD#PBF is available at Aetrix Electronics and suitable for distributed power systems, embedded computing platforms, and communications infrastructure requiring stable component supply, long-term lifecycle support, and guaranteed −40°C to +85°C operation.
Supply support for LTC3879IUD#PBF 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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC3879 belongs to ADI's high-efficiency synchronous buck controller product line, designed specifically for demanding DC/DC conversion in telecom, datacom, and industrial applications where wide input range, fast transient response, and MOSFET RDS(ON)-based current sensing are essential.
FAQ
What is the operating temperature range for the LTC3879IUD#PBF?
The LTC3879IUD#PBF is specified and guaranteed over the industrial temperature range of −40°C to +85°C. This rating applies across all electrical specifications in the datasheet, including feedback reference accuracy, current limit thresholds, and gate driver performance - ensuring reliable operation in base station, networking, and factory automation environments.
Does the LTC3879IUD#PBF require an external current sense resistor?
No, the LTC3879IUD#PBF does not require an external current sense resistor. It implements No RSENSE valley current mode control by measuring the voltage drop across the bottom N-channel MOSFET's RDS(ON) between SW and PGND pins. The VRNG pin allows scaling of the current sense threshold from 22mV to 98mV to accommodate MOSFET on-resistance variation with temperature and process.
How is switching frequency set on the LTC3879IUD#PBF?
Switching frequency on the LTC3879IUD#PBF is set by connecting a resistor (RON) from VIN to the ION pin. The on-time tON is inversely proportional to ION current, yielding pseudo-fixed frequency operation that compensates for input voltage variation. For example, a 432kΩ resistor sets ~400kHz at VIN = 12V, as shown in Figure 3 of the datasheet.
Can the LTC3879IUD#PBF start up into a pre-biased output?
Yes, the LTC3879IUD#PBF supports smooth start-up into a pre-biased output. When the TRACK/SS pin is held above the internal 0.6V reference at power-on, the controller regulates VFB to match the TRACK/SS voltage rather than forcing a hard zero-to-rail ramp - preventing reverse current flow and ensuring safe sequencing in multi-rail systems.
What package type is used for the LTC3879IUD#PBF?
The LTC3879IUD#PBF uses a 16-lead (3mm × 3mm) plastic QFN package with an exposed thermal pad (Pin 17 = SGND). This thermally enhanced package provides θJA = 68°C/W and θJC = 4.2°C/W, enabling high-power density designs when the exposed pad is properly soldered to a PCB ground plane.
LTC3879IUD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LTC3879IUD#PBF FAQ
1.How can I place an order for LTC3879IUD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3879IUD#PBF 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 LTC3879IUD#PBF reliable?
The price and inventory of LTC3879IUD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3879IUD#PBF is usually 5 days.
3.What payment methods are accepted for LTC3879IUD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3879IUD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3879IUD#PBF?
LTC3879IUD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3879IUD#PBF 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 LTC3879IUD#PBF?
For technical support, including LTC3879IUD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3879IUD#PBF requirements.
6.How does Aetrix verify that LTC3879IUD#PBF is sourced from the original manufacturer or authorized distributors?
All LTC3879IUD#PBF 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 LTC3879IUD#PBF meets industry standards.
7.What is the process for return or replacement of LTC3879IUD#PBF?
All LTC3879IUD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3879IUD#PBF, 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 LTC3879IUD#PBF part is unused and in its original packaging.
Return procedure for LTC3879IUD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LTC3879IUD#PBF 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…
