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Analog Devices Inc. LTC3869EUF#TRPBF
- Part No.:
- LTC3869EUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LTC3869EUF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,152
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Product details
Overview
LTC3869EUF#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 LTC3869EUF#TRPBF datasheet, LTC3869EUF#TRPBF pinout, LTC3869EUF#TRPBF application, or LTC3869EUF#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 LTC3869EUF#TRPBF implements a constant-frequency current-mode architecture with two independent control loops, each featuring an error amplifier (EA), current comparator (ICMP), and slope compensation. Its 180° phase shift between channels reduces input ripple current and enables shared input capacitance in high-current applications.
It integrates dual N-channel gate drivers (TG/BG) with 2.6 Ω pull-up and 1.5 Ω pull-down RDS(ON), a 5 V INTVCC LDO, programmable frequency via FREQ pin (10 µA sink), and MODE/PLLIN-selectable operating modes: Burst Mode®, pulse-skipping, or forced continuous conduction - with external clock synchronization capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4 V to 38 V - accommodates 12 V, 24 V, and 36 V battery/bus systems without external regulators. |
| Output Voltage Accuracy | ±0.75% at 0.6 V - ensures tight regulation for modern low-voltage ASICs and FPGAs. |
| Switching Frequency | 250 kHz to 780 kHz - adjustable via FREQ pin; enables optimization of size vs. efficiency in high-density designs. |
| Current Sensing | RSENSE or DCR - supports lossless inductor sensing or precision shunt-based current monitoring. |
| Phase Configuration | 180° out-of-phase dual controllers - cuts required input capacitance by ~50% and suppresses supply-induced noise. |
| Soft-Start Control | Independent TK/SS1/TK/SS2 pins - enable staggered startup or precise voltage tracking between rails. |
| Protection Features | Foldback current limiting, output overvoltage lockout (±10%), and undervoltage lockout (3.2 V) - prevent MOSFET thermal runaway and system fault propagation. |
Pinout & Package
The LTC3869EUF#TRPBF is housed in a 28-lead (4 mm × 4 mm) plastic QFN package with exposed pad (Pin 29 = SGND), optimized for thermal performance and compact layout. The exposed pad must be soldered to PCB ground.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| SGND (Pin 29) | Signal Ground Reference | Reference node for all small-signal circuitry and compensation networks; connects to PGND at single point for noise isolation. |
| VIN (Pin 19) | Main Input Supply | Primary power source for internal circuits and gate drivers; requires local 0.1–1 µF decoupling to PGND. |
| INTVCC (Pin 18) | Internal 5 V Regulator Output | Supplies control logic and drivers; requires ≥4.7 µF low-ESR capacitor to PGND; not intended for external loads. |
| TG1/TG2 (Pins 22,14) | Top Gate Driver Outputs | Floating high-side drivers with INTVCC-referenced swing; drive gate of upper N-MOSFETs in synchronous buck stages. |
| BG1/BG2 (Pins 20,17) | Bottom Gate Driver Outputs | Ground-referenced drivers for lower N-MOSFETs; feature anti-shoot-through logic and fast 25 ns transition times. |
| SENSE1+/SENSE2+ (Pins 27,8) | Current Sense Positive Inputs | Accept voltage from RSENSE or DCR network; bias current ±1 µA ensures minimal sensing error. |
| TK/SS1/TK/SS2 (Pins 1,6) | Soft-Start & Tracking Inputs | Internal 1.2 µA current charges external capacitor for controlled ramp-up; also accepts external reference for rail tracking. |
| MODE/PLLIN (Pin 24) | Operating Mode Selector | Selects Burst Mode®, pulse-skipping, or forced CCM; also accepts external clock for synchronization (PLL mode). |
| FREQ (Pin 25) | Frequency Programming Input | Sinks precise 10 µA current; resistor to ground sets oscillator frequency from 250 kHz to 780 kHz. |
| PGOOD (Pin 12) | Power Good Monitor Output | Open-drain indicator asserting low when either output deviates >±10% from target after 20 µs mask timer. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased control | Reduces RMS input ripple current by ~70%, enabling smaller input capacitors and lower EMI in high-current supplies. |
| OPTI-LOOP® compensation | Allows stable loop response across wide variations in output capacitance (10 µF–1000 µF) and ESR (0.5 mΩ–50 mΩ). |
| RSENSE or DCR sensing | Eliminates need for dedicated sense resistors in cost-sensitive or thermally constrained designs using DCR sensing. |
| Accurate multiphase current matching | Ensures balanced load sharing between phases - critical for thermal management and reliability in >50 A applications. |
| Independent soft-start/tracking | Enables safe sequencing of multiple rails (e.g., core vs. I/O) without external timing ICs or discrete logic. |
Applications
| Server VRMs | Telecom Power Modules |
|---|---|
Use Scenario: Dual-phase 1.8 V/15 A and 1.2 V/12 A CPU/GPU core supplies in 1U rack servers. IC Role / Device Role / Timing Role: Dual synchronous buck controller managing interleaved switching, current balancing, and precise voltage tracking during dynamic load transients. Use Value: Achieves >94% peak efficiency at full load while maintaining <±1% cross-regulation and <10 mV output ripple under 10 A/µs load steps. | Use Scenario: Redundant -48 V to +3.3 V/5 V intermediate bus converters in 5G base station power shelves. IC Role / Device Role / Timing Role: Dual-phase controller delivering tightly regulated outputs with synchronized switching to minimize conducted EMI on shared backplane buses. Use Value: Enables 180° phase offset to halve input capacitor RMS current, reducing footprint and thermal stress in space-constrained telecom modules. |
| Industrial PLC Power | Medical Imaging Power Supplies |
Use Scenario: Isolated 24 V input to 5 V/3.3 V/1.8 V triple-output power for programmable logic controllers with strict EMC requirements. IC Role / Device Role / Timing Role: Dual-channel controller implementing independent soft-start and tracking to meet IEC 61000-4-11 immunity and hold-up time specs. Use Value: Delivers accurate rail sequencing and foldback current limiting to protect downstream FPGA and ADCs during brownout conditions. | Use Scenario: High-stability 12 V and 5 V auxiliary supplies for CT/MRI detector front-ends requiring ultra-low noise and zero output voltage droop. IC Role / Device Role / Timing Role: Dual-phase controller operating in forced continuous conduction mode to eliminate low-frequency switching artifacts in analog signal chains. Use Value: Maintains <10 µVpp output noise and ±0.01% line/load regulation - critical for sub-millivolt ADC reference stability. |
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 |
|---|---|---|---|
| LTC3850IUFD#TRPBF | Pin-compatible with LTC3869; fixed 500 kHz frequency; no MODE/PLLIN pin; lacks OPTI-LOOP® and ILIM programming. | Best suited for cost-optimized, fixed-frequency designs where burst mode and flexible current limit are unnecessary. | Select when design prioritizes simplicity and BOM reduction over adaptive light-load efficiency and programmable protection. |
| ISL95812IRZ-T7A | Supports 3-phase operation; integrated MOSFET drivers only (no external FET control); no DCR sensing; 0.6 V ±1% accuracy. | Targeted at notebook CPU VRMs; lacks independent tracking/soft-start pins and wide VIN range. | Choose only for compact, integrated 3-phase solutions where external FET control and 4–38 V input are not required. |
Compared with LTC3850IUFD#TRPBF and ISL95812IRZ-T7A, the LTC3869EUF#TRPBF offers superior flexibility in frequency tuning, light-load efficiency modes, and sensing options - making it optimal for high-performance, multi-rail industrial and telecom power systems demanding precise sequencing and thermal resilience.
Availability
LTC3869EUF#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 traceable sourcing.
Supply support for LTC3869EUF#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 renowned for precision DC/DC controllers and robust power solutions.
The LTC3869EUF#TRPBF belongs to Linear's PolyPhase® controller family, designed specifically for high-current, low-voltage digital power delivery in computing, communications, and industrial infrastructure where efficiency, thermal balance, and rail sequencing are critical.
FAQ
What is the maximum operating frequency of the LTC3869EUF#TRPBF?
The LTC3869EUF#TRPBF supports a phase-lockable switching frequency range from 250 kHz to 780 kHz. This is set via the FREQ pin, which sinks a precise 10 µA current - connecting a resistor from FREQ to ground determines the nominal frequency. At VFREQ = 2.4 V or higher, the device achieves its maximum rated frequency of 780 kHz, enabling compact magnetics and high transient response in space-constrained applications.
Does the LTC3869EUF#TRPBF support DCR current sensing?
Yes, the LTC3869EUF#TRPBF fully supports both RSENSE and DCR current sensing methods. Its SENSE1+/SENSE1− and SENSE2+/SENSE2− inputs accept differential signals from either discrete sense resistors or the voltage drop across inductor DCR, with ±1 µA input bias current ensuring minimal measurement error. This flexibility allows designers to eliminate power-wasting sense resistors in thermally sensitive or high-efficiency applications.
How does the OPTI-LOOP® compensation in the LTC3869EUF#TRPBF improve design flexibility?
The OPTI-LOOP® compensation in the LTC3869EUF#TRPBF dynamically adjusts loop response to accommodate wide variations in output capacitance (10 µF to 1000 µF) and ESR (0.5 mΩ to 50 mΩ). Unlike traditional Type II/III compensators requiring manual RC tuning, OPTI-LOOP® maintains stability and transient performance across diverse ceramic, polymer, and electrolytic capacitor selections - reducing design iterations and qualification time for multi-platform power systems.
Can the LTC3869EUF#TRPBF be synchronized to an external clock?
Yes, the LTC3869EUF#TRPBF can be synchronized to an external clock via the MODE/PLLIN pin. When an external clock signal is applied to this pin, the internal oscillator locks to it in PLL mode, forcing both channels into continuous conduction and aligning their switching edges. This capability eliminates beat frequencies in multi-controller systems and simplifies EMI filtering in densely packed power architectures.
What is the purpose of the ILIM pin on the LTC3869EUF#TRPBF?
The ILIM pin on the LTC3869EUF#TRPBF selects one of three maximum current sense threshold levels: 25 mV (ILIM = GND), 50 mV (ILIM = float), or 75 mV (ILIM = INTVCC). This programmability allows designers to optimize current-limit accuracy and MOSFET SOA margin across varying input/output conditions - for example, selecting 50 mV for standard operation or 25 mV for high-current, low-RDS(on) FETs to avoid premature foldback.
LTC3869EUF#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)
LTC3869EUF#TRPBF FAQ
1.How can I place an order for LTC3869EUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3869EUF#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 LTC3869EUF#TRPBF reliable?
The price and inventory of LTC3869EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3869EUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3869EUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3869EUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3869EUF#TRPBF?
LTC3869EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3869EUF#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 LTC3869EUF#TRPBF?
For technical support, including LTC3869EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3869EUF#TRPBF requirements.
6.How does Aetrix verify that LTC3869EUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3869EUF#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 LTC3869EUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3869EUF#TRPBF?
All LTC3869EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3869EUF#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 LTC3869EUF#TRPBF part is unused and in its original packaging.
Return procedure for LTC3869EUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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