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Analog Devices Inc. LTC3850IGN-2#TRPBF
- Part No.:
- LTC3850IGN-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 28-SSOP (0.154", 3.90mm Width)
- Datasheet:
-
LTC3850IGN-2#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 28SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,478
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Product details
Overview
LTC3850IGN-2#TRPBF from Analog Devices (formerly Linear Technology) is a dual, 2-phase synchronous step-down switching controller driving all-N-channel MOSFET stages. It delivers up to 95% efficiency, supports 4V–30V input, provides ±1% 0.8V reference accuracy, and operates at phase-lockable frequencies from 250kHz to 780kHz - used in high-density DC/DC conversion for notebook computers and portable instrumentation.
For engineers reviewing the LTC3850IGN-2#TRPBF datasheet, LTC3850IGN-2#TRPBF pinout, LTC3850IGN-2#TRPBF application, or LTC3850IGN-2#TRPBF equivalent, key selection criteria include dual-phase current-mode control, independent soft-start/tracking, RSENSE/DCR sensing flexibility, output overvoltage protection, and 28-pin narrow SSOP packaging with thermal performance θJA = 95°C/W.
Technical Context
The LTC3850IGN-2#TRPBF implements constant-frequency current-mode control with two independent 180° out-of-phase channels, each featuring an error amplifier (EA), transconductance gm = 2.2 mmho, and ITH-controlled peak current limiting. Its OPTI-LOOP® compensation adapts transient response across wide output capacitance and ESR ranges.
Phase synchronization is achieved via MODE/PLLIN pin (accepting external clock) and FREQ/PLLFLTR pin (configuring PLL loop filter or setting DC frequency). The IC supports three light-load modes - Burst Mode®, pulse-skipping, and forced continuous conduction - selected by MODE/PLLIN voltage level or floating state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4V to 30V - covers common battery chemistries (Li-ion, Li-Po) and intermediate bus rails (5V, 12V, 24V). |
| Output Voltage Accuracy | ±1% at 0.8V reference - ensures tight regulation for modern low-voltage digital loads (e.g., 1.8V, 2.5V, 3.3V). |
| Switching Frequency | 250kHz to 780kHz, phase-lockable - enables EMI reduction via synchronization and trade-off between efficiency and magnetics size. |
| Efficiency | Up to 95% - minimizes thermal load and extends battery runtime in portable systems. |
| Current Sensing | RSENSE or DCR - eliminates sense resistor losses in high-current designs or enables precise current limiting with discrete resistors. |
| Protection Features | Output overvoltage lockout (±7.5%), foldback current limiting, power good (PGOOD) with 17μs mask - ensures system-level fault containment without external circuitry. |
| Soft-Start & Tracking | Independent TK/SS1/TK/SS2 pins with 1.3μA internal charge current - enables controlled ramp-up and supply sequencing for multi-rail processors/FPGAs. |
Pinout & Package
Package: 28-lead narrow plastic SSOP (GN), –40°C to +85°C operating temperature range, lead-free finish, tape-and-reel packaging (LTC3850IGN-2#TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN1, RUN2 | Channel enable/disable inputs | Independent shutdown control per channel; 1.22V threshold with hysteresis enables robust sequencing and fault isolation. |
| SENSE1+/SENSE2+, SENSE1–/SENSE2– | Differential current sense inputs | High-impedance inputs (±1μA bias) support Kelvin-connected RSENSE or DCR networks with wide 0V–5V common-mode range. |
| VFB1, VFB2 | Feedback voltage inputs | Compare output divider voltage against 0.8V reference; ±1% accuracy maintained over temperature and line/load conditions. |
| TK/SS1, TK/SS2 | Soft-start and tracking inputs | Internal 1.3μA current charges external capacitor to generate linear voltage ramp - sets output rise time and enables master-slave rail tracking. |
| MODE/PLLIN | Mode selection & external sync input | Selects Burst Mode® (floating), pulse-skipping (tied to INTVCC), or forced CCM (tied to SGND); accepts external clock for deterministic phase alignment. |
| PGOOD | Open-drain power-good indicator | Pulled low if either VFB deviates >±7.5% or during soft-start - provides system-level power sequencing and fault signaling with 17μs debounce. |
| TG1/TG2, BG1/BG2 | Top/bottom gate drivers | Drive N-MOSFET gates with 2.6Ω/1.5Ω (TG) and 2.4Ω/1.1Ω (BG) on-resistance; 25ns transition times support high-frequency operation. |
| BOOST1/BOOST2 | Floating bootstrap supplies | Enable high-side N-MOSFET drive; swing from ~INTVCC–0.7V to VIN+INTVCC - requires external bootstrap capacitors tied to SW nodes. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 180° phased controllers | Reduces input ripple current by ~70% versus single-phase, cutting required input capacitance and lowering EMI emissions. |
| OPTI-LOOP® compensation | Enables stable loop response across diverse ceramic/polymer output caps (10μF–1000μF) and ESR (0.5mΩ–50mΩ) without redesign. |
| Independent TK/SS pins | Supports asymmetric soft-start timing and precise voltage tracking between rails (e.g., core vs. I/O) using resistor dividers or external ramps. |
| Three selectable light-load modes | Burst Mode® (highest light-load efficiency), pulse-skipping (low ripple/audio noise), or forced CCM (lowest output ripple, best transient response). |
| Pre-biased output startup | Allows safe start-up into pre-charged outputs - critical for hot-swap and multi-rail systems where downstream loads retain residual voltage. |
Applications
| Notebook Power Management | Portable Instrumentation |
|---|---|
Use Scenario: Dual-rail CPU/GPU core and I/O supply generation in space-constrained ultrabooks. IC Role / Device Role / Timing Role: Dual-phase synchronous buck controller managing 3.3V/2.5V or 1.8V/1.2V rails with interleaved switching and coordinated soft-start. Use Value: Reduces input capacitor count by 50%, lowers thermal stress on PCB, and meets strict EN55022 Class B conducted EMI limits via phase cancellation. | Use Scenario: Battery-powered handheld test equipment requiring clean, sequenced analog and digital supplies. IC Role / Device Role / Timing Role: Primary DC/DC controller delivering regulated 5V, 3.3V, and 1.8V rails from single Li-ion cell (3.0–4.2V) or 12V adapter input. Use Value: Pre-biased startup prevents latch-up during hot insertion; ±1% output accuracy ensures ADC/DAC reference stability and measurement repeatability. |
| DC Power Distribution Systems | Battery-Operated Digital Devices |
Use Scenario: Intermediate bus converter in industrial IoT gateway aggregating multiple sensor nodes. IC Role / Device Role / Timing Role: High-efficiency 12V-to-5V/3.3V dual-output stage feeding downstream POL converters and microcontrollers. Use Value: 95% peak efficiency extends backup runtime; PGOOD output enables centralized power health monitoring and graceful shutdown. | Use Scenario: Power management for portable medical devices (e.g., ultrasound handhelds) with strict battery life and EMI requirements. IC Role / Device Role / Timing Role: Main system regulator supplying FPGA, memory, and RF transceiver from 2-cell Li-ion (6–8.4V) input. Use Value: Burst Mode® operation achieves <25μA quiescent current at light load, extending standby time beyond 72 hours on typical battery capacity. |
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 |
|---|---|---|---|
| ISL95836IRZ-T7A | Single-chip dual-phase controller with integrated MOSFET drivers only; no external bootstrap diode requirement; fixed 500kHz frequency. | Targeted at Intel VR12/VR12.5 CPU power delivery; lacks independent TK/SS pins and RSENSE/DCR flexibility. | Choose ISL95836IRZ-T7A for Intel-compliant notebook platforms needing plug-and-play compatibility and reduced BOM count. |
| MP8765GL-Z | Monolithic dual-phase buck with integrated high-/low-side FETs; max 16V input; no external gate drivers or bootstrap components. | Optimized for compact consumer electronics; lacks phase-lock capability, PGOOD flag, and programmable light-load modes. | Choose MP8765GL-Z when board space is critical and input voltage stays below 16V; not suitable for 24V industrial or wide-input battery systems. |
Compared with ISL95836IRZ-T7A and MP8765GL-Z, the LTC3850IGN-2#TRPBF offers wider input range (4V–30V), full external component control for thermal/power optimization, and flexible sequencing - making it preferred for ruggedized, multi-chemistry, or custom-designed power systems.
Availability
LTC3850IGN-2#TRPBF is available at Aetrix Electronics and suitable for notebook computing, portable instrumentation, DC power distribution systems, and battery-operated digital devices requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LTC3850IGN-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, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LTC3850IGN-2#TRPBF belongs to the LTC38xx family of high-efficiency, dual-phase synchronous buck controllers designed for demanding portable, industrial, and telecom power applications requiring precision regulation, low quiescent current, and robust fault protection.
FAQ
What is the maximum input voltage rating for the LTC3850IGN-2#TRPBF?
The LTC3850IGN-2#TRPBF has an absolute maximum input supply voltage (VIN) of 30V, with a transient rating of 34V for durations under 500ms when INTVCC ≥ 5V. Operation above 30V risks permanent damage; design margin should maintain VIN ≤ 28V for reliability across temperature and lifetime.
Does the LTC3850IGN-2#TRPBF support pre-biased output startup?
Yes, the LTC3850IGN-2#TRPBF supports pre-biased output startup - a critical feature for hot-swap and multi-rail systems. During startup, the controller avoids reverse current flow into a pre-charged output by disabling bottom-FET discharge until the top-FET begins switching, preventing output voltage collapse or latch-up.
How does the MODE/PLLIN pin configure light-load operation on the LTC3850IGN-2#TRPBF?
The MODE/PLLIN pin selects light-load behavior: floating enables Burst Mode® (highest efficiency, discontinuous conduction), tied to INTVCC enables pulse-skipping mode (low ripple, moderate efficiency), and tied to SGND forces continuous conduction mode (lowest ripple, lowest light-load efficiency). This pin also serves as the external clock input for phase synchronization.
What is the purpose of the TK/SS pins on the LTC3850IGN-2#TRPBF?
The TK/SS1 and TK/SS2 pins on the LTC3850IGN-2#TRPBF provide independent soft-start ramp control and output voltage tracking. Each pin sources a precise 1.3μA current to charge an external capacitor, generating a linear voltage ramp that directly controls the output voltage rise time - enabling coordinated sequencing or master-slave rail tracking without external circuitry.
Can the LTC3850IGN-2#TRPBF be synchronized to an external clock source?
Yes, the LTC3850IGN-2#TRPBF can be synchronized to an external clock via the MODE/PLLIN pin. When driven by a clean square wave (250kHz–780kHz), the internal phase-locked loop locks the oscillator to the external signal, forcing continuous conduction mode and aligning switching edges - essential for EMI reduction and multi-controller coherence in dense power systems.
LTC3850IGN-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 ~ 30V
- Frequency - Switching:
- 250kHz ~ 780kHz
- Duty Cycle (Max):
- 97.2%
- Synchronous Rectifier:
- Yes
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable, Frequency Control, Power Good, Soft Start, Tracking
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SSOP
LTC3850IGN-2#TRPBF FAQ
1.How can I place an order for LTC3850IGN-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC3850IGN-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 LTC3850IGN-2#TRPBF reliable?
The price and inventory of LTC3850IGN-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 LTC3850IGN-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC3850IGN-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC3850IGN-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC3850IGN-2#TRPBF?
LTC3850IGN-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC3850IGN-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 LTC3850IGN-2#TRPBF?
For technical support, including LTC3850IGN-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC3850IGN-2#TRPBF requirements.
6.How does Aetrix verify that LTC3850IGN-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC3850IGN-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 LTC3850IGN-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC3850IGN-2#TRPBF?
All LTC3850IGN-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC3850IGN-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 LTC3850IGN-2#TRPBF part is unused and in its original packaging.
Return procedure for LTC3850IGN-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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