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Analog Devices Inc. LTC3869IUF#TRPBF
- Part No.:
- LTC3869IUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3869IUF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:2,532
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Product details
Overview
LTC3869IUF#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 with phase-locked constant-frequency current mode control up to 780 kHz, supports 4 V to 38 V input, delivers 0.6 V to 12.5 V output per channel, and achieves up to 95% efficiency in server power rails.
For engineers reviewing the LTC3869IUF#TRPBF datasheet, LTC3869IUF#TRPBF pinout, LTC3869IUF#TRPBF application, or LTC3869IUF#TRPBF equivalent, key selection criteria include dual-phase current matching accuracy (±0.75% VFB), RSENSE/DCR sensing flexibility, OPTI-LOOP® compensation for wide output capacitor/ESR ranges, and independent soft-start/tracking via TK/SS pins.
Technical Context
The LTC3869IUF#TRPBF implements two independent current-mode control loops with 180° phase offset, minimizing input ripple and EMI. Each channel features a transconductance error amplifier (gm = 2 mmho), programmable current sense threshold (25–82 mV, selectable via ILIM pin), and integrated slope compensation for stability across duty cycles.
Its oscillator supports frequency setting via external resistor on FREQ pin (250–780 kHz), synchronization via MODE/PLLIN, and three operating modes-Burst Mode® (high light-load efficiency), pulse-skipping, or forced continuous conduction-selected by MODE/PLLIN voltage level or floating state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4 V to 38 V - supports 12 V/24 V industrial bus, 12–36 V battery systems, and telecom -48 V derived supplies. |
| Output Voltage Range | 0.6 V to 12.5 V - enables direct regulation of core voltages (e.g., 1.2 V, 1.8 V) and I/O rails (3.3 V, 5 V, 12 V). |
| Feedback Accuracy | ±0.75% at 0.6 V - ensures tight regulation under load transients and temperature variation for CPU/GPU VRMs. |
| Switching Frequency | 250 kHz to 780 kHz - adjustable via FREQ pin; high end enables smaller magnetics; phase-lockable for noise-sensitive systems. |
| Current Sense Threshold | 25 mV / 50 mV / 75 mV - selectable via ILIM pin grounding/floating/INTVCC connection, enabling precise overcurrent protection tuning. |
| Efficiency | Up to 95% - achieved using dual N-channel synchronous drive, low RDS(ON) gate drivers (TG: 2.6 Ω pull-up, BG: 1.1 Ω pull-down), and optimized dead-time control. |
| Thermal Performance | θJA = 37°C/W - enabled by 4 mm × 4 mm QFN package with exposed SGND pad soldered to PCB thermal plane. |
Pinout & Package
Package: 28-lead (4 mm × 4 mm) plastic QFN with exposed SGND pad (Pin 29), rated for –40°C to 125°C junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 (Pins 26, 9) | Channel enable control inputs | Independent shutdown: <1.2 V disables respective channel; internal 1 µA pull-up enables restart; logic-compatible interface. |
| VFB1, VFB2 (Pins 3, 4) | Error amplifier feedback inputs | Connect to resistor dividers from outputs; regulate to 0.6 V reference with ±0.75% accuracy over full temp range. |
| ITH1, ITH2 (Pins 2, 5) | Error amplifier output / current limit threshold | Set peak inductor current; voltage determines PWM on-time; used for loop compensation and current foldback. |
| TK/SS1, TK/SS2 (Pins 1, 6) | Soft-start and tracking inputs | Internal 1.2 µA current charges external capacitor for controlled ramp-up; also accepts master supply voltage for sequencing. |
| MODE/PLLIN (Pin 24) | Operating mode select & sync input | Ground = forced CCM; INTVCC = pulse-skipping; float = Burst Mode®; external clock = synchronization source. |
| FREQ (Pin 25) | Frequency programming node | 10 µA precision current sink; connect resistor to SGND to set 250–780 kHz; enables accurate multi-controller phase alignment. |
| TG1, TG2 (Pins 22, 14) | Top gate driver outputs | Floating drivers with 2.6 Ω pull-up / 1.5 Ω pull-down; drive high-side N-MOSFET gates referenced to SW nodes. |
| BG1, BG2 (Pins 20, 17) | Bottom gate driver outputs | PGND-referenced drivers with 2.4 Ω pull-up / 1.1 Ω pull-down; optimized for fast turn-on/turn-off of low-side N-MOSFETs. |
| SENSE1+, SENSE1− (Pins 27, 28) | Differential current sense inputs | Accept RSENSE or DCR network signals; support bidirectional sensing; ±1 µA bias current minimizes error. |
| PGOOD (Pin 12) | Power-good open-drain output | Asserts low when either VOUT deviates >±10% from target after 20 µs debounce; enables system power sequencing. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input capacitance requirement by ~50% and suppresses input ripple-induced noise in shared power buses. |
| OPTI-LOOP® compensation | Enables stable loop response across wide output capacitor values (10 µF–1000 µF) and ESR ranges without manual tuning. |
| RSENSE or DCR current sensing | Eliminates need for dedicated sense resistors; supports lossless inductor-based sensing for higher efficiency in high-current designs. |
| Independent TK/SS soft-start | Allows staggered or tracked startup of dual outputs-critical for FPGA, ASIC, and multi-rail processor power sequencing. |
| Output overvoltage protection | Hardware-level VOVL lockout at 0.64–0.68 V on VFB pins prevents damage during feedback divider fault or transient events. |
| 5 V internal LDO (INTVCC) | Supplies gate drivers and logic; bypassable via EXTVCC ≥4.7 V to improve efficiency when using regulated auxiliary supply. |
Applications
| Server VRM | Telecom Power Shelf |
|---|---|
|
Use Scenario: Dual-output 1.2 V/10 A + 3.3 V/5 A regulation for CPU core and I/O power in 1U rack servers. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing interleaved switching, current sharing, and precise voltage tracking. Use Value: Achieves 94.5% efficiency at full load while maintaining <±5 mV output deviation across line/load/temperature; reduces thermal stress via 180° phase shift. |
Use Scenario: Redundant 48 V-to-12 V/20 A intermediate bus converter in telecom power distribution units. IC Role / Device Role / Timing Role: High-vin dual controller supporting wide input range and robust fault handling for -48 V telecom systems. Use Value: Enables single-chip dual-phase design with current foldback limiting and PGOOD sequencing-reducing BOM count vs. discrete controllers. |
| Industrial PLC Power | Medical Imaging Module |
|
Use Scenario: Isolated 24 V input powering 5 V/3 A and 3.3 V/3 A rails for microcontroller, ADC, and communication interfaces in harsh environments. IC Role / Device Role / Timing Role: Dual-channel controller with independent RUN/TK-SS pins enabling safe power-up sequencing and channel-level fault isolation. Use Value: Supports extended temperature operation (–40°C to 125°C), UVLO hysteresis (0.6 V), and input overvoltage tolerance (40 V max) for industrial reliability. |
Use Scenario: Low-noise 12 V/5 A and 1.8 V/8 A supplies for FPGA-based image processing and analog front-end in portable ultrasound devices. IC Role / Device Role / Timing Role: Dual-phase controller with Burst Mode® operation and programmable frequency to minimize conducted EMI in sensitive analog sections. Use Value: Delivers <10 mVpp output ripple in CCM mode and <20 µA quiescent current in Burst Mode®, extending battery runtime. |
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 |
|---|---|---|---|
| LTC3850EUF#TRPBF | Pin-compatible predecessor; fixed 500 kHz frequency; no ILIM-selectable current sense threshold; lacks OPTI-LOOP®. | Suitable for cost-sensitive, fixed-frequency designs where dynamic compensation and fine current limit tuning are unnecessary. | Select LTC3850 if legacy layout reuse is critical and advanced features like programmable sense threshold or wide-bandwidth loop tuning are not required. |
| MP2953GQ-Z | Monolithic dual-phase controller (integrated MOSFETs); lower Vin range (4.5–16 V); no EXTVCC option; different pinout and compensation scheme. | Targeted at compact, low-input-voltage applications (e.g., notebook, SSD); not suitable for 24–36 V industrial or telecom inputs. | Choose MP2953 only for space-constrained 12 V input systems requiring integration; LTC3869IUF#TRPBF remains preferred for high-Vin, high-efficiency, and layout-flexible designs. |
Compared with LTC3850EUF#TRPBF and MP2953GQ-Z, the LTC3869IUF#TRPBF offers superior flexibility in frequency programming, current-sense threshold selection, and loop compensation-making it optimal for high-performance, thermally demanding, and multi-rail industrial/server applications where discrete MOSFETs and layout control are essential.
Availability
LTC3869IUF#TRPBF is available at Aetrix Electronics and suitable for server systems, telecom power shelves, and industrial PLCs requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.
Supply support for LTC3869IUF#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 power management portfolio with rigorous qualification and long-term product support.
The LTC3869IUF#TRPBF belongs to Linear's PolyPhase® dual/multiphase controller family, designed specifically for high-current, low-voltage DC/DC conversion in datacenter, telecom, and industrial infrastructure where efficiency, thermal performance, and reliability are critical.
FAQ
What is the maximum switching frequency supported by the LTC3869IUF#TRPBF?
The LTC3869IUF#TRPBF supports a phase-lockable fixed-frequency range from 250 kHz to 780 kHz. The upper limit is achieved when the FREQ pin voltage exceeds 2.4 V, and the oscillator remains stable and jitter-free across temperature and input voltage variations. This high-frequency capability allows use of smaller inductors and capacitors in space-constrained designs.
Does the LTC3869IUF#TRPBF support both RSENSE and DCR current sensing?
Yes, the LTC3869IUF#TRPBF supports both RSENSE and DCR current sensing on each channel via its differential SENSE+ and SENSE− inputs. The device includes built-in filtering and bias current compensation (±1 µA) to ensure accuracy with either method, enabling flexible, lossless current monitoring in high-efficiency power stages.
How does the ILIM pin affect current limit behavior in the LTC3869IUF#TRPBF?
The ILIM pin on the LTC3869IUF#TRPBF selects one of three maximum current sense thresholds: 25 mV (ILIM = GND), 50 mV (ILIM = float), or 75 mV (ILIM = INTVCC). This directly sets the peak inductor current trip point per channel, allowing precise overcurrent protection tuning without external components or resistor changes.
Can the LTC3869IUF#TRPBF be used in single-output, 2-phase configurations?
Yes, the LTC3869IUF#TRPBF supports single-output multiphase operation. To configure it, tie together ITH1/ITH2, VFB1/VFB2, TK/SS1/TK/SS2, and RUN1/RUN2 pins. The device provides accurate current matching between phases (<2 mV mismatch), ensuring balanced thermal loading and optimal power delivery in high-current VRMs.
What thermal performance can be expected from the LTC3869IUF#TRPBF in its 4 mm × 4 mm QFN package?
The LTC3869IUF#TRPBF in the 4 mm × 4 mm QFN (UFD) package has a junction-to-ambient thermal resistance (θJA) of 37°C/W when the exposed SGND pad (Pin 29) is properly soldered to a minimum 1-in² copper thermal plane. This enables reliable operation at full load up to 125°C junction temperature in well-ventilated industrial environments.
LTC3869IUF#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 (4x4)
LTC3869IUF#TRPBF FAQ
1.How can I place an order for LTC3869IUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3869IUF#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 LTC3869IUF#TRPBF reliable?
The price and inventory of LTC3869IUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3869IUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3869IUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3869IUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3869IUF#TRPBF?
LTC3869IUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3869IUF#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 LTC3869IUF#TRPBF?
For technical support, including LTC3869IUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3869IUF#TRPBF requirements.
6.How does Aetrix verify that LTC3869IUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3869IUF#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 LTC3869IUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3869IUF#TRPBF?
All LTC3869IUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3869IUF#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 LTC3869IUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3869IUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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