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Analog Devices Inc. LTC3869EUFD#TRPBF
- Part No.:
- LTC3869EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3869EUFD#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:6,290
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Product details
Overview
LTC3869EUFD#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 operates at phase-locked frequencies up to 780 kHz, delivers ±0.75% output voltage accuracy at 0.6 V, supports 4 V–38 V input and 0.6 V–12.5 V output ranges, and minimizes input capacitor ESR noise via 180° out-of-phase operation - used in high-efficiency server and telecom power supplies.
For engineers reviewing the LTC3869EUFD#TRPBF datasheet, LTC3869EUFD#TRPBF pinout, LTC3869EUFD#TRPBF application, or LTC3869EUFD#TRPBF equivalent, key selection criteria include dual-channel current matching tolerance, RSENSE/DCR sensing flexibility, OPTI-LOOP® compensation adaptability, and precise soft-start/tracking control via independent TK/SS pins.
Technical Context
The LTC3869EUFD#TRPBF implements constant-frequency current-mode control with two independent error amplifiers (EA), each regulating its channel's ITH voltage to set peak inductor current. Its phase-locked oscillator accepts external synchronization via MODE/PLLIN and supports frequency programming from 250 kHz to 780 kHz using the FREQ pin's 10 µA current source.
It integrates dual N-channel gate drivers (TG/BG) with 25 ns transition times, internal 5 V INTVCC LDO (±2% regulation), and programmable current limit thresholds (25/45/68 mV) selected by ILIM pin state - enabling robust short-circuit foldback and accurate multiphase current sharing across channels.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4 V to 38 V - accommodates 12 V/24 V industrial rails and multi-cell Li-ion battery inputs without external pre-regulation. |
| Output Voltage Accuracy | ±0.75% at 0.6 V - ensures tight regulation for low-voltage ASIC/FPGA core supplies under load and temperature variation. |
| Switching Frequency Range | 250 kHz to 780 kHz - adjustable via FREQ pin; enables optimization of size (higher f) vs. efficiency (lower f) in compact power designs. |
| Current Sense Threshold | 25 mV / 45 mV / 68 mV - selectable via ILIM pin grounding/floating/INTVCC connection, allowing precise MOSFET RDS(on) or DCR-based current sensing. |
| Feedback Reference Voltage | 0.600 V (±0.75%) - stable over –40°C to 125°C junction range, enabling accurate remote sensing for point-of-load regulation. |
| Gate Driver Output Capability | TG/BG rise/fall time ≤25 ns (CL = 3300 pF) - supports fast-switching GaN or low-Qg Si MOSFETs with minimal dead-time loss. |
| Soft-Start Current | 1.25 µA typical - charges external TK/SS capacitor linearly, enabling controlled ramp-up of dual outputs with tracking capability. |
| Power Good Threshold | ±10% of regulated VOUT - provides reliable system sequencing and fault detection with 20 µs debounce timer. |
Pinout & Package
Package: 28-lead (4 mm × 5 mm) plastic QFN with exposed thermal pad (Pin 29 = SGND). Requires soldering of exposed pad to PCB ground for thermal performance (θJA = 34°C/W) and signal integrity.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 (Pins 26, 9) | Channel enable control inputs | Independent shutdown per channel; 1.22 V threshold with 80 mV hysteresis; internal 1 µA pull-up enables self-start. |
| VFB1, VFB2 (Pins 3, 4) | Error amplifier feedback inputs | Compare output voltage divider ratio against 0.6 V reference; support remote sensing for ±0.75% accuracy. |
| ITH1, ITH2 (Pins 2, 5) | Error amplifier output / current threshold | Set peak inductor current per channel; voltage directly controls PWM on-time in current-mode architecture. |
| TK/SS1, TK/SS2 (Pins 1, 6) | Soft-start and tracking inputs | Internal 1.25 µA current ramps external capacitor; enables independent or coincident output ramp-up with external supply tracking. |
| MODE/PLLIN (Pin 24) | Operating mode select & sync input | Selects Burst Mode® (float), pulse-skipping (INTVCC), or forced CCM (SGND); accepts external clock for phase-locking. |
| FREQ (Pin 25) | Frequency programming node | 10 µA precision current sink - connect resistor to SGND to set switching frequency from 250 kHz to 780 kHz. |
| ILIM (Pin 10) | Current limit threshold select | GND/FLOAT/INTVCC sets max sense voltage to 25/45/68 mV - critical for accurate current foldback during short-circuit events. |
| TG1, TG2 (Pins 22, 14) | Top N-MOSFET gate drivers | Floating drivers with INTVCC-referenced swing; drive bootstrap capacitors for high-side N-channel MOSFETs. |
| BG1, BG2 (Pins 20, 17) | Bottom N-MOSFET gate drivers | PGND-referenced drivers; turn on/off synchronous rectifiers with 25 ns transitions and anti-shoot-through logic. |
| SENSE1+/2+, SENSE1–/2– (Pins 27/8, 28/7) | Differential current sense inputs | Accept RSENSE or DCR networks; ±1 µA bias current enables Kelvin sensing for accurate current measurement. |
| PGOOD (Pin 12) | Open-drain power-good indicator | Asserts low when either VOUT deviates >±10%; includes 20 µs blanking to suppress startup transients. |
| SGND (Pin 29) | Signal ground reference | Exposed thermal pad; must be soldered to PCB ground plane - serves as analog reference for all small-signal circuitry. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase dual control | Reduces RMS input ripple current by ~30%, cutting required input capacitance and lowering conducted EMI in shared-input systems. |
| OPTI-LOOP® compensation | Enables stable loop response across wide output capacitor ESR (0.5 mΩ–100 mΩ) and capacitance (10 µF–1000 µF) variations without redesign. |
| Accurate multiphase current matching | Guarantees <2 mV channel-to-channel VSENSE(MAX) mismatch - ensures balanced thermal loading and derating in parallel-phase configurations. |
| Three current-limit threshold options | Configurable 25/45/68 mV thresholds via ILIM pin eliminate need for external resistors when adapting to different MOSFET RDS(on) or DCR values. |
| Independent soft-start and tracking | Separate TK/SS pins allow staggered startup, voltage sequencing, or precise tracking of master supply - essential for FPGA/CPU core-I/O rail coordination. |
| Integrated 5 V INTVCC regulator | Delivers up to 100 mA at 5.0 V ±2% from VIN; supports external EXTVCC switchover to improve efficiency when powering from auxiliary rail. |
Applications
| Server VRMs | Telecom Power Modules |
|---|---|
Use Scenario: Dual-output 1.8 V/1.2 V VRM for multi-core CPU and memory subsystems in 1U rack servers. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing independent current loops with precise tracking and phase interleaving. Use Value: Reduces input capacitor count by 40% versus single-phase design while maintaining <±10 mV output regulation under 10 A/µs load transients. | Use Scenario: Compact 48 V-to-12 V/5 V dual-rail converter in optical line cards requiring low-noise, high-density power. IC Role / Device Role / Timing Role: Phase-locked dual controller operating at 500 kHz with synchronized switching to minimize magnetic coupling and EMI in dense PCB layouts. Use Value: Achieves >92% full-load efficiency at 48 V input while meeting EN55022 Class B conducted emissions without added shielding. |
| Industrial PLC Power Supplies | Medical Imaging Subsystems |
Use Scenario: 24 V input to isolated 5 V/3.3 V power for I/O modules and microcontroller domains in harsh factory environments. IC Role / Device Role / Timing Role: Dual-channel controller with independent RUN pins enabling selective rail shutdown during sleep modes and fault isolation. Use Value: Enables <50 µA shutdown current per channel and supports wide-temp operation (–40°C to 125°C) without derating. | Use Scenario: High-reliability 28 V battery-powered 1.2 V/1.8 V supply for FPGA-based image processing engines in portable ultrasound units. IC Role / Device Role / Timing Role: Dual-phase controller with Burst Mode® operation extending battery runtime while maintaining <10 mV output ripple during imaging bursts. Use Value: Delivers >89% efficiency at 100 mA load in Burst Mode®, doubling operational time versus forced CCM in standby imaging states. |
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; lacks ILIM-selectable current sense threshold and has narrower 200 kHz–600 kHz frequency range. | Suitable for cost-sensitive legacy designs where 68 mV current limit and 780 kHz operation are not required. | Choose LTC3850 if existing layout reuse is critical and advanced current foldback or higher frequency is unnecessary. |
| MP2918GL-Z | Monolithic dual-phase controller (integrated MOSFETs); fixed 600 kHz frequency; no external FREQ pin or ILIM configuration. | Targets space-constrained applications where board area > efficiency optimization; requires no external high-side drivers. | Choose MP2918 for simplified BOM and layout in mid-power (<30 A total) applications where discrete MOSFET flexibility is not needed. |
Compared with LTC3850EUFD#TRPBF and MP2918GL-Z, the LTC3869EUFD#TRPBF offers superior design flexibility through programmable current limits, wider frequency range, and independent channel control - making it optimal for high-performance, thermally constrained, or multi-rail sequencing applications.
Availability
LTC3869EUFD#TRPBF is available at Aetrix Electronics and suitable for server VRMs, telecom power modules, and industrial PLC power supplies requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across –40°C to 125°C.
Supply support for LTC3869EUFD#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 technical and manufacturing continuity for the LTC portfolio. Linear pioneered high-performance power management ICs with emphasis on precision, efficiency, and reliability.
The LTC3869EUFD#TRPBF belongs to Linear's high-efficiency dual-phase controller product line, designed specifically for demanding intermediate bus and point-of-load applications in datacenter, telecom, and industrial systems where thermal density and transient response are critical.
FAQ
What is the maximum supported switching frequency for the LTC3869EUFD#TRPBF?
The LTC3869EUFD#TRPBF supports a phase-lockable switching frequency up to 780 kHz, set via the FREQ pin's 10 µA current sink and an external resistor to SGND. At VFREQ ≥ 2.4 V, the nominal frequency reaches 780 kHz (typical), with guaranteed operation from 250 kHz to 780 kHz across temperature and supply conditions.
How does the ILIM pin affect current limiting on the LTC3869EUFD#TRPBF?
The ILIM pin on the LTC3869EUFD#TRPBF selects one of three maximum current sense thresholds: 25 mV (ILIM = GND), 45 mV (ILIM = float), or 68 mV (ILIM = INTVCC). This directly configures the peak current comparator trip point per channel, enabling precise foldback protection matched to specific MOSFET RDS(on) or DCR sense network gains.
Can the LTC3869EUFD#TRPBF operate with only one channel enabled?
Yes - the LTC3869EUFD#TRPBF supports independent channel control. Pulling RUN1 low disables Channel 1 while leaving Channel 2 fully operational, and vice versa. Both channels retain full functionality including soft-start, current sensing, and PGOOD monitoring when used singly.
What thermal considerations apply to the LTC3869EUFD#TRPBF in the 4 mm × 5 mm QFN package?
The LTC3869EUFD#TRPBF in the UFD package has θJA = 34°C/W when the exposed SGND pad (Pin 29) is properly soldered to a minimum 1-in² copper pour. Junction temperature must remain ≤125°C; for 12 V input, 5 V/10 A output at 500 kHz, typical power dissipation is ~1.2 W, requiring ≤35°C ambient rise above board temperature.
Does the LTC3869EUFD#TRPBF support output voltage tracking between channels?
Yes - the LTC3869EUFD#TRPBF supports precise output voltage tracking via independent TK/SS1 and TK/SS2 pins. Connecting a resistor divider from the master output to TK/SS2 configures Channel 2 to ramp identically to Channel 1, enabling controlled sequencing for core/I/O rail coordination in FPGAs and processors.
LTC3869EUFD#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)
LTC3869EUFD#TRPBF FAQ
1.How can I place an order for LTC3869EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3869EUFD#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 LTC3869EUFD#TRPBF reliable?
The price and inventory of LTC3869EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3869EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3869EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3869EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3869EUFD#TRPBF?
LTC3869EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3869EUFD#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 LTC3869EUFD#TRPBF?
For technical support, including LTC3869EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3869EUFD#TRPBF requirements.
6.How does Aetrix verify that LTC3869EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3869EUFD#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 LTC3869EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3869EUFD#TRPBF?
All LTC3869EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3869EUFD#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 LTC3869EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LTC3869EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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