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Analog Devices Inc. LTC3869IGN-2#TRPBF
- Part No.:
- LTC3869IGN-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3869IGN-2#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,967
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Product details
Overview
LTC3869IGN-2#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 180° out-of-phase outputs (4V–38V input, 0.6V–12.5V output), phase-lockable 250kHz–780kHz frequency, ±0.75% output voltage accuracy, and supports RSENSE or DCR current sensing - deployed in telecom power supplies and high-density server VRMs.
For engineers reviewing the LTC3869IGN-2#TRPBF datasheet, LTC3869IGN-2#TRPBF pinout, LTC3869IGN-2#TRPBF application, or LTC3869IGN-2#TRPBF equivalent, key selection considerations include its SSOP-28 package, independent soft-start/tracking (TK/SS1/2), MODE/PLLIN-configurable operating modes (Burst/Pulse-Skipping/Continuous), and dual-channel current matching for balanced thermal stress in multiphase designs.
Technical Context
The LTC3869IGN-2#TRPBF implements constant-frequency current-mode control with two independent error amplifiers (EA), each regulating its channel via ITH voltage-controlled peak current limit and VFB-referenced 0.6V feedback loop. Its OPTI-LOOP® compensation adapts transient response across wide output capacitance and ESR ranges.
It features dual N-channel gate drivers (TG/BG) with 25ns transition times, integrated 5V INTVCC LDO, EXTVCC switchover at 4.7V, and programmable current sense thresholds (25–82mV) via ILIM pin configuration - enabling precise foldback limiting and robust short-circuit protection without external sense resistors.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 38V - supports 12V/24V industrial rails and wide-range battery inputs (e.g., 4S Li-ion up to 38V max). |
| Output Voltage Range | 0.6V to 12.5V - enables direct regulation of core voltages (1.2V, 1.8V) and intermediate bus rails (3.3V, 5V, 12V). |
| Feedback Accuracy | ±0.75% at 0.6V - ensures tight regulation critical for CPU/GPU core supplies where <1% deviation impacts stability. |
| Switching Frequency | 250kHz to 780kHz (phase-lockable) - allows EMI optimization and inductor size reduction while maintaining 180° interleaving. |
| Current Sense Threshold | 25mV / 50mV / 75mV (ILIM = GND/FLOAT/INTVCC) - configures overcurrent protection level without changing sense resistor values. |
| Efficiency | Up to 95% - achieved via synchronous N-MOSFET drive, low RDS(ON) gate drivers (TG RDOWN = 1.5Ω), and optimized dead-time control. |
| Thermal Performance | θJA = 80°C/W (SSOP-28) - requires moderate PCB copper area for 125°C junction operation under full load. |
Pinout & Package
The LTC3869IGN-2#TRPBF is housed in a 28-lead narrow plastic SSOP package (5.6mm × 17.9mm, 0.635mm pitch), with exposed thermal pad not present (unlike QFN variants). Pin 1 is top-left corner, pin count increases left-to-right on top row (1–14), then right-to-left on bottom row (15–28).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 (Pins 27, 10) | Channel enable/disable control | 1.22V threshold with 80mV hysteresis; independent shutdown per channel preserves system-level sequencing control. |
| VFB1, VFB2 (Pins 4, 5) | Error amplifier feedback input | Connects to resistor divider from output; regulates to 0.6V reference with ±0.75% accuracy over temperature. |
| ITH1, ITH2 (Pins 3, 6) | Error amplifier output / current limit setpoint | Controls peak inductor current; voltage range 0.5V–1.6V maps to full-scale current sense threshold. |
| TK/SS1, TK/SS2 (Pins 2, 7) | Soft-start ramp / tracking input | 1.25µA internal charge current enables linear VOUT ramp-up; supports master-slave voltage tracking in multi-rail systems. |
| MODE/PLLIN (Pin 25) | Operating mode select / external sync input | Configures Burst Mode (float), Pulse-Skipping (INTVCC), or Continuous (GND); accepts external clock for synchronization. |
| FREQ (Pin 26) | Frequency setting input | 10µA precision current sink; 100kΩ to GND sets ~500kHz - enables accurate frequency tuning without oscillator drift. |
| ILIM (Pin 11) | Current sense threshold select | Three-state logic (GND/FLOAT/INTVCC) selects 25/50/75mV max sense voltage - eliminates need for multiple sense resistors. |
| TG1, TG2 (Pins 23, 15) | Top N-MOSFET gate driver output | High-side floating driver with BOOST1/BOOST2 supply; 2.6Ω pull-up / 1.5Ω pull-down ensures fast turn-on/turn-off. |
| BG1, BG2 (Pins 21, 18) | Bottom N-MOSFET gate driver output | Low-side driver referenced to PGND; 2.4Ω pull-up / 1.1Ω pull-down minimizes conduction loss in synchronous rectification. |
| SENSE1+, SENSE1− (Pins 28, 1) | Differential current sense input (Ch1) | Accepts RSENSE or DCR network; ±1µA bias current enables high-accuracy sensing with minimal offset impact. |
| PGOOD (Pin 13) | Power-good open-drain output | Asserts after 20µs delay when both VOUT1/VOUT2 are within ±10% - provides reliable system power sequencing signal. |
Key Features
| Feature | Design Value |
|---|---|
| 180° out-of-phase dual controllers | Reduces RMS input ripple current by ~30%, cutting required input capacitance and lowering EMI filter size/cost. |
| OPTI-LOOP® compensation | Enables stable loop response across 10× variation in output capacitor ESR (e.g., ceramic vs. polymer) without re-tuning. |
| Independent TK/SS soft-start | Allows staggered startup of dual outputs or precise voltage tracking between rails (e.g., VDDQ following VDD in DDR memory). |
| Programmable current foldback | ILIM-selectable thresholds (25/50/75mV) provide scalable short-circuit protection without redesigning sense networks. |
| Three selectable light-load modes | Burst Mode (highest efficiency), Pulse-Skipping (low noise), or Continuous (lowest ripple) - configurable per system requirement. |
| Integrated 5V INTVCC regulator | Eliminates need for external bias supply; EXTVCC switchover at 4.7V enables efficient self-bias from regulated output rail. |
Applications
| Telecom Power Supply | Server Voltage Regulator Module (VRM) |
|---|---|
|
Use Scenario: Dual-output 12V input to 3.3V/1.8V conversion in 48V-powered base station line cards. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing parallel power stages with interleaved switching to reduce input/output ripple. Use Value: 180° phase shift cuts input capacitor RMS current by 30%, enabling smaller 1210-case ceramics instead of larger tantalums. |
Use Scenario: High-current CPU core supply (up to 100A) using two LTC3869IGN-2#TRPBF in parallel for single 1.2V output. IC Role / Device Role / Timing Role: Multiphase controller with matched current sharing - channels synchronized via shared ITH/VFB/TK-SS nets. Use Value: ±1% inter-channel current mismatch ensures balanced thermal loading across MOSFETs, extending board lifetime at 125°C ambient. |
| Industrial PLC Power Distribution | Medical Imaging System DC-DC Conversion |
|
Use Scenario: Isolated 24V input powering 5V logic and 3.3V FPGA rails in ruggedized programmable logic controller. IC Role / Device Role / Timing Role: Dual independent buck controller providing isolated, sequenced outputs with individual RUN pin control. Use Value: Independent RUN1/RUN2 pins enable firmware-controlled power-up sequencing to prevent FPGA configuration faults during cold start. |
Use Scenario: Low-noise 12V input to 1.2V/1.8V conversion for ADC/DAC front-end in MRI signal processing module. IC Role / Device Role / Timing Role: Dual-channel controller operating in Pulse-Skipping Mode to suppress audible switching noise while maintaining <10mVpp ripple. Use Value: Pulse-Skipping avoids sub-20kHz switching artifacts that could couple into sensitive analog signal paths. |
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 |
|---|---|---|---|
| MP2953GQ-Z (Monolithic Power) | Integrated MOSFETs (40V/10A), fixed 500kHz freq, no ILIM pin - requires external current sense resistor for foldback. | Lower BOM count but limited to ≤10A per phase; lacks programmable soft-start and tracking capability. | Select MP2953GQ-Z only when board space is constrained and current requirements stay below 10A per phase. |
| LTC3850IUFD#TRPBF | Pin-compatible with LTC3869, but fixed 500kHz freq, no MODE/PLLIN flexibility, lower max freq (600kHz), no EXTVCC support. | Same SSOP-28 footprint but lacks Burst Mode and external sync - unsuitable for EMI-sensitive or ultra-low-quiescent designs. | Choose LTC3850IUFD#TRPBF only if legacy design reuse is required and advanced light-load efficiency is not needed. |
Compared with MP2953GQ-Z and LTC3850IUFD#TRPBF, the LTC3869IGN-2#TRPBF delivers superior design flexibility through programmable frequency, three light-load modes, and ILIM-selectable current limits - making it optimal for high-reliability, thermally constrained, or EMI-sensitive dual-rail systems.
Availability
LTC3869IGN-2#TRPBF is available at Aetrix Electronics and suitable for telecom infrastructure, server VRMs, and industrial PLCs requiring stable component supply with guaranteed long-term availability and traceable sourcing.
Supply support for LTC3869IGN-2#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 product support, documentation, and manufacturing continuity for the LTC portfolio.
The LTC3869IGN-2#TRPBF belongs to Linear's high-performance power controller family, designed specifically for high-efficiency, high-density, multi-phase DC/DC conversion in demanding computing and communications applications.
FAQ
What is the maximum input voltage rating for the LTC3869IGN-2#TRPBF?
The LTC3869IGN-2#TRPBF has an absolute maximum input voltage (VIN) rating of 40V. Its operational input range is specified from 4V to 38V, making it suitable for 24V industrial systems and 4S Li-ion battery inputs (nominal 14.8V, max ~16.8V) with headroom for transients. Exceeding 40V risks permanent damage per Absolute Maximum Ratings.
Does the LTC3869IGN-2#TRPBF support current sensing using DCR of the output inductor?
Yes, the LTC3869IGN-2#TRPBF supports both RSENSE and DCR current sensing. Its SENSE1+/SENSE1− and SENSE2+/SENSE2− inputs accept differential signals from either discrete sense resistors or RC networks across inductor windings. The ±1µA bias current and low offset ensure accurate DCR sensing even at low duty cycles.
How does the ILIM pin affect current limit behavior in the LTC3869IGN-2#TRPBF?
The ILIM pin on the LTC3869IGN-2#TRPBF selects one of three maximum current sense thresholds: 25mV (ILIM = GND), 50mV (ILIM = FLOAT), or 75mV (ILIM = INTVCC). This directly scales the peak inductor current trip point without changing external components - enabling flexible overcurrent protection tuning across load conditions.
Can the LTC3869IGN-2#TRPBF be used in single-output, two-phase configurations?
Yes, the LTC3869IGN-2#TRPBF supports single-output multiphase operation. Tie ITH1/ITH2, VFB1/VFB2, TK/SS1/TK/SS2, and RUN1/RUN2 together to force identical regulation and synchronized soft-start. Its ±1% channel current matching ensures balanced thermal stress and optimal current sharing in such configurations.
What is the purpose of the MODE/PLLIN pin on the LTC3869IGN-2#TRPBF?
The MODE/PLLIN pin on the LTC3869IGN-2#TRPBF serves dual functions: selecting operating mode (Burst Mode when floating, Pulse-Skipping when tied to INTVCC, Continuous when grounded) and accepting external clock signals for synchronization. This enables EMI reduction via frequency dithering or alignment with system clocks in noise-sensitive applications.
LTC3869IGN-2#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-SSOP (0.154", 3.90mm Width)
- 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:
- Yes
- 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-SSOP
LTC3869IGN-2#TRPBF FAQ
1.How can I place an order for LTC3869IGN-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3869IGN-2#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 LTC3869IGN-2#TRPBF reliable?
The price and inventory of LTC3869IGN-2#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC3869IGN-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3869IGN-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3869IGN-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3869IGN-2#TRPBF?
LTC3869IGN-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3869IGN-2#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 LTC3869IGN-2#TRPBF?
For technical support, including LTC3869IGN-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3869IGN-2#TRPBF requirements.
6.How does Aetrix verify that LTC3869IGN-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3869IGN-2#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 LTC3869IGN-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3869IGN-2#TRPBF?
All LTC3869IGN-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3869IGN-2#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 LTC3869IGN-2#TRPBF part is unused and in its original packaging.
Return procedure for LTC3869IGN-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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