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Analog Devices Inc. LTC3869IUFD#TRPBF
- Part No.:
- LTC3869IUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3869IUFD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,650
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Product details
Overview
LTC3869IUFD#TRPBF from Analog Devices (formerly Linear Technology) is a dual, 2-phase synchronous step-down DC/DC controller driving all-N-channel MOSFET stages. It delivers ±0.75% output voltage accuracy at 0.6V, supports 4V–38V input and 0.6V–12.5V output ranges, operates up to 780kHz with phase-lockable frequency, and minimizes input capacitor ESR noise via 180° out-of-phase operation - used in high-power server and telecom power supplies.
For engineers reviewing the LTC3869IUFD#TRPBF datasheet, LTC3869IUFD#TRPBF pinout, LTC3869IUFD#TRPBF application, or LTC3869IUFD#TRPBF equivalent, key selection criteria include dual-phase current matching accuracy, RSENSE/DCR sensing flexibility, OPTI-LOOP® compensation for wide output capacitance tolerance, foldback current limiting, and independent soft-start/tracking control per channel.
Technical Context
The LTC3869IUFD#TRPBF implements constant-frequency current-mode control with two independent 180°-phased channels, each featuring an error amplifier (EA), current comparator (ICMP), and slope compensation. Its OPTI-LOOP® architecture dynamically adjusts loop response by scaling transconductance (gm = 2 mmho) and ITH voltage sensitivity across output capacitance and ESR variations.
It integrates dual N-channel gate drivers (TG/BG) with 25ns transition times, 30ns dead-time control, and internal 5V INTVCC regulator (4.8–5.2V, ±2% load regulation). The MODE/PLLIN pin enables selection among Burst Mode®, pulse-skipping, or forced continuous conduction - with external clock synchronization capability up to 780kHz.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports 12V/24V industrial buses and multi-cell Li-ion battery inputs without external pre-regulation. |
| Output Voltage Accuracy | ±0.75% at 0.6V - ensures tight regulation for low-voltage ASIC/FPGA core rails under full temperature range (–40°C to 125°C). |
| Switching Frequency | 250kHz to 780kHz, phase-lockable - enables EMI reduction via external clock sync and optimal magnetics sizing for high-density designs. |
| Current Sensing | RSENSE or DCR sensing - eliminates need for dedicated sense resistors in high-current applications, reducing power loss and board space. |
| Efficiency | Up to 95% - achieved via synchronous N-MOSFET drive, low RDS(ON) gate drivers (TG RDOWN = 1.5Ω), and optimized light-load modes. |
| Thermal Performance | θJA = 34°C/W (UFD package) - enables 5A/channel operation without forced airflow in compact 4mm × 5mm QFN layout. |
| Protection Features | Foldback current limiting, output overvoltage lockout (±10% at VFB), undervoltage lockout (3.2V with 0.6V hysteresis) - prevents MOSFET thermal runaway and system fault propagation. |
Pinout & Package
Package: 28-lead (4mm × 5mm) plastic QFN (UFD), exposed pad (Pin 29) soldered to SGND for thermal and electrical integrity. θJA = 34°C/W, operating junction temperature up to 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 29) | Signal Ground Reference | Reference node for all small-signal circuitry (error amps, comparators); must connect to PGND at single point to avoid ground loops. |
| VIN (Pin 19) | Main Input Supply | Primary power source for INTVCC regulator and gate driver bias; requires local 0.1–1µF ceramic decoupling to PGND. |
| INTVCC (Pin 18) | Internal 5V Regulator Output | Supplies control logic and gate drivers; requires ≥4.7µF low-ESR capacitor to PGND; not intended for external loads. |
| TG1/TG2 (Pins 22, 14) | Top Gate Driver Outputs | Floating drivers for high-side N-MOSFETs; swing from ~INTVCC below SW node to VIN + INTVCC; require bootstrap capacitors. |
| BG1/BG2 (Pins 20, 17) | Bottom Gate Driver Outputs | PGND-referenced drivers for low-side N-MOSFETs; 25ns rise/fall time ensures minimal shoot-through risk. |
| SENSE1+/SENSE2+ (Pins 27, 8) | Current Sense Positive Inputs | Accept DCR network or sense resistor signals; bias current ±1µA minimizes sensing error in precision applications. |
| VFB1/VFB2 (Pins 3, 4) | Error Amplifier Feedback Inputs | Compare output voltage (via resistor divider) against 0.6V reference; ±50nA input current enables high-impedance feedback networks. |
| TK/SS1/TK/SS2 (Pins 1, 6) | Soft-Start & Tracking Inputs | Internal 1.2µA current ramps external capacitor for controlled startup; also accepts master supply tracking signal for coordinated rail sequencing. |
| MODE/PLLIN (Pin 24) | Operating Mode & Sync Input | Selects Burst Mode® (float), pulse-skipping (tied to INTVCC), or forced CCM (tied to SGND); accepts external clock for phase locking. |
| FREQ (Pin 25) | Frequency Setting Input | 10µA precision current sink sets oscillator frequency via external resistor; enables accurate, temperature-stable frequency programming. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input ripple current by ~70%, enabling smaller input capacitors and lower EMI in high-current systems like server VRMs. |
| OPTI-LOOP® compensation | Automatically adapts loop gain to maintain stable transient response across ±50% variation in output capacitance and ESR - critical for polymer/tantalum/ceramic hybrid outputs. |
| Independent TK/SS pins | Enable per-channel soft-start ramping or precise voltage tracking between 1.2V and 5V rails - essential for FPGA/ASIC power sequencing compliance. |
| Current foldback limiting | Reduces MOSFET power dissipation during short-circuit events by lowering peak current threshold as VOUT drops - prevents thermal failure without external circuitry. |
| Power Good (PGOOD) monitor | Open-drain output asserts after 20µs mask timer when either channel deviates >±10% from setpoint - provides reliable system reset signaling. |
| EXTVCC switchover | Switches INTVCC supply from internal LDO to external 4.7–6V source, improving efficiency by bypassing linear regulator losses in multi-rail systems. |
Applications
| Server VRM Power Delivery | Telecom Line Card Supplies |
|---|---|
|
Use Scenario: Dual-output 1.8V/1.2V power for CPU/GPU cores in 1U rack servers with strict thermal and ripple constraints. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing parallel inductor currents with <2% channel-to-channel mismatch. Use Value: 180° phasing cuts input RMS current by 40%, reducing bulk capacitor count and PCB area while maintaining <10mV p-p output ripple. |
Use Scenario: High-efficiency 3.3V/5V conversion for packet processing ASICs in carrier-grade line cards with -48V backplane input. IC Role / Device Role / Timing Role: Dual-channel controller operating in Burst Mode® at light load to achieve >85% efficiency down to 10mA output current. Use Value: Enables 24/7 operation with <150mW quiescent loss at no load, meeting GR-1089 Class B EMI and NEBS thermal requirements. |
| Industrial PLC Power Modules | Medical Imaging Power Subsystems |
|
Use Scenario: Robust 5V/3.3V dual-rail supply for programmable logic controllers exposed to 40V transients on 24V DC input bus. IC Role / Device Role / Timing Role: Controller with 40V absolute max VIN rating and integrated UVLO hysteresis (0.6V) for reliable brownout recovery. Use Value: Eliminates need for external TVS/clamp circuits; withstands ISO 16750-2 Pulse 4a (load dump) without latch-up or parameter shift. |
Use Scenario: Low-noise, tightly regulated 1.0V/1.8V supplies for high-speed ADC/DAC arrays in portable ultrasound systems. IC Role / Device Role / Timing Role: Dual-phase controller using OPTI-LOOP® to stabilize loop with 1000µF polymer output caps and 20mΩ ESR. Use Value: Achieves <50µs load transient recovery (2A step) with <15mV undershoot - preserves signal integrity in 16-bit data converters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-phase synchronous buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3850EUFD#TRPBF | Pin-compatible predecessor; fixed 500kHz frequency, no PLL sync, no EXTVCC switchover, lower max frequency (600kHz). | Lacks phase-locking and flexible light-load mode selection - unsuitable for EMI-sensitive or multi-rail synchronized systems. | Choose LTC3850 only if design uses fixed frequency and does not require Burst Mode® or external clock sync. |
| MP2918GL-Z | Monolithic dual-phase controller (integrated MOSFETs); 4.5–16V input; 0.6–5.5V output; 600kHz max; no DCR sensing support. | Higher integration reduces BOM count but limits max current (30A total) and input voltage range - not viable for 38V industrial or telecom inputs. | Choose MP2918 for cost-sensitive, lower-power (<20A) applications where board space is constrained and 38V input is unnecessary. |
Compared with LTC3850EUFD#TRPBF and MP2918GL-Z, the LTC3869IUFD#TRPBF offers superior flexibility in frequency tuning, light-load efficiency optimization, and high-input-voltage robustness - making it the preferred choice for demanding server, telecom, and industrial power systems requiring long-term reliability and design scalability.
Availability
LTC3869IUFD#TRPBF is available at Aetrix Electronics and suitable for server systems, telecom infrastructure, and industrial PLCs requiring stable component supply, extended temperature operation (–40°C to 125°C), and long-lifecycle availability.
Supply support for LTC3869IUFD#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. Linear Technology was founded in 1981 and specialized in precision, high-reliability power ICs for demanding applications.
The LTC3869IUFD#TRPBF belongs to Linear's high-efficiency multiphase controller product line, designed specifically for high-current, low-voltage DC/DC conversion in computing, communications, and industrial equipment where thermal density and transient response are critical.
FAQ
What is the maximum input voltage rating for the LTC3869IUFD#TRPBF?
The LTC3869IUFD#TRPBF has an absolute maximum input voltage rating of 40V on the VIN pin. Its operational input range is specified from 4V to 38V, making it suitable for 24V industrial buses and multi-cell battery systems. Exceeding 40V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3869IUFD#TRPBF support DCR current sensing?
Yes, the LTC3869IUFD#TRPBF explicitly supports both RSENSE and DCR current sensing via its SENSE1+/SENSE1– and SENSE2+/SENSE2– pins. This allows elimination of power-wasting sense resistors in high-current applications, using the inductor's inherent DCR for accurate current measurement.
How does the OPTI-LOOP® compensation in the LTC3869IUFD#TRPBF improve design flexibility?
The OPTI-LOOP® compensation in the LTC3869IUFD#TRPBF automatically adjusts loop gain based on output capacitance and ESR, enabling stable operation across diverse capacitor types (ceramic, polymer, tantalum) without manual compensation redesign. This reduces qualification time for multi-capacitor BOMs.
Can the LTC3869IUFD#TRPBF be synchronized to an external clock?
Yes, the LTC3869IUFD#TRPBF can be synchronized to an external clock via the MODE/PLLIN pin. When driven with a clean square wave, the internal oscillator locks to the external frequency (250kHz–780kHz), enabling EMI reduction and multi-converter phase alignment in dense power systems.
What is the purpose of the EXTVCC pin on the LTC3869IUFD#TRPBF?
The EXTVCC pin on the LTC3869IUFD#TRPBF allows bypassing the internal 5V LDO by supplying 4.7–6V externally - typically from a downstream converter output. This improves overall system efficiency by eliminating LDO dropout losses, especially in multi-rail architectures where one rail powers another.
LTC3869IUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 2
- Output Phases:
- 2
- Voltage - Supply (Vcc/Vdd):
- 4V ~ 38V
- Frequency - Switching:
- 250kHz ~ 780kHz
- Duty Cycle (Max):
- 95%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LTC3869IUFD#TRPBF FAQ
1.How can I place an order for LTC3869IUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3869IUFD#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 LTC3869IUFD#TRPBF reliable?
The price and inventory of LTC3869IUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3869IUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3869IUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3869IUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3869IUFD#TRPBF?
LTC3869IUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3869IUFD#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 LTC3869IUFD#TRPBF?
For technical support, including LTC3869IUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3869IUFD#TRPBF requirements.
6.How does Aetrix verify that LTC3869IUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3869IUFD#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 LTC3869IUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3869IUFD#TRPBF?
All LTC3869IUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3869IUFD#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 LTC3869IUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3869IUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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