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Analog Devices Inc. LTC1771IS8#TRPBF
- Part No.:
- LTC1771IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1771IS8#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,464
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Product details
Overview
LTC1771IS8#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency current-mode step-down DC/DC controller driving an external P-channel MOSFET, featuring 10µA no-load quiescent current, 2.8V–20V input range, and ±2% output voltage accuracy over temperature. It supports up to 5A output current with 100% duty cycle for low-dropout operation and is optimized for battery-powered systems requiring ultralow standby power.
For engineers reviewing the LTC1771IS8#TRPBF datasheet, LTC1771IS8#TRPBF pinout, LTC1771IS8#TRPBF application, or LTC1771IS8#TRPBF equivalent, key selection considerations include its constant off-time architecture, Burst Mode™ enable/disable via MODE pin, programmable soft-start via RUN/SS, current-sense threshold of 140mV max, and MSOP-8 thermal performance (θJA = 200°C/W).
Technical Context
The LTC1771IS8#TRPBF implements a constant off-time, current-mode control architecture with a fixed 3.5µs off-time at regulation and up to 70µs during fault conditions. Its error amplifier output (ITH pin) directly controls peak inductor current, while internal 1.23V reference and feedback comparator (VFB pin) enable precise output voltage regulation across line and load transients.
It integrates micropower shutdown (2µA IQ), defeatable Burst Mode™ operation for sub-mA efficiency, and robust protection including short-circuit detection via SENSE pin, 100% duty cycle capability, and thermal shutdown at TJ = 125°C. The device operates across –40°C to +85°C and requires no external compensation for basic stability due to OPTI-LOOP™ architecture on ITH.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 20V - supports single- to quad-cell Li-ion, 5V/12V rails, and wide industrial inputs without external regulators. |
| No-Load Supply Current | 10µA - enables multi-week battery life in always-on portable instruments and wireless modems. |
| Feedback Reference Voltage | 1.23V ±2% - sets output voltage via external resistor divider; stable over –40°C to +85°C. |
| Max Output Current | 5A - achievable with appropriate external P-MOSFET, sense resistor, and inductor; limited by thermal design and RSENSE. |
| Current Sense Threshold | 110–140mV - programs peak switch current; determines maximum load and short-circuit trip point. |
| Off-Time Duration | 3.5µs (typical) - defines minimum switching frequency (~285kHz at VOUT/VIN = 0.5); extends to 70µs under short-circuit for safe inductor discharge. |
| Shutdown Current | 2µA - reduces system standby power to near-zero; activated by pulling RUN/SS below 0.5V. |
| Package Thermal Resistance | θJA = 200°C/W (MSOP-8) - requires minimal PCB copper for thermal management in space-constrained designs. |
Pinout & Package
Package: 8-Lead MSOP (MS8), RoHS-compliant, exposed pad not electrically connected. Dimensions: 3.0mm × 3.0mm × 1.1mm, pitch 0.65mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (Pin 1) | Enable & Soft-Start Control | Pull below 0.5V for shutdown (IQ = 2µA); connect capacitor for linear soft-start ramp (1µA charge current). |
| ITH (Pin 2) | Error Amplifier Output | Controls peak inductor current; voltage range 0–3V; used for loop compensation and burst threshold clamping. |
| VFB (Pin 3) | Feedback Input | Compares divided output voltage to 1.23V reference; 10nA input bias enables high-resistor-divider networks. |
| GND (Pin 4) | Analog & Power Ground | Common return for feedback, error amp, and internal references; separate from PGATE return path. |
| PGATE (Pin 5) | P-Channel MOSFET Driver | High-current gate driver (1A peak); swings from GND to VIN; drives external high-side switch. |
| VIN (Pin 6) | Main Power Input | Supplies internal circuitry and PGATE driver; accepts 2.8V–20V; absolute max 20V. |
| SENSE (Pin 7) | Current Sense Input | Monitors voltage drop across external RSENSE; sets current limit and Burst Mode entry threshold. |
| MODE (Pin 8) | Burst Mode Enable | Connect to VIN (>2V) to enable Burst Mode™; tie to GND to disable for low-noise continuous operation. |
Key Features
| Feature | Design Value |
|---|---|
| Constant Off-Time Architecture | Enables stable operation across wide VIN/VOUT ratios without external frequency programming; simplifies EMI filtering. |
| Defeatable Burst Mode™ | Reduces no-load IQ to 9µA (sleep mode) and enables >90% efficiency down to 1mA load; disable via MODE pin for noise-sensitive applications. |
| 100% Duty Cycle Capability | Supports dropout operation (VIN ≈ VOUT); critical for battery end-of-life support in Li-ion systems. |
| Integrated Soft-Start | Programmed via external capacitor on RUN/SS; prevents inrush current and enables controlled power sequencing. |
| Short-Circuit Protection | Auto-recovering current limiting via SENSE pin; no latch-up; protects MOSFET and inductor during sustained faults. |
| OPTI-LOOP™ Compensation | Single-pole compensation on ITH pin eliminates need for complex Type II/III networks; ensures stability with diverse output capacitors. |
Applications
| Cellular Telephones | Portable Medical Instruments |
|---|---|
Use Scenario: Power management in compact 3G/4G handsets with dual-core processors and RF front-end requiring clean, efficient 3.3V or 2.8V rails. IC Role / Device Role / Timing Role: Step-down controller regulating battery voltage (3.4–4.2V) to stable core/peripheral voltages; manages dynamic load steps up to 2A. Use Value: 10µA quiescent current extends talk time; Burst Mode™ maintains >85% efficiency at 100µA sleep current; MSOP-8 footprint saves board area. | Use Scenario: Battery-powered glucose meters and handheld ultrasound probes needing regulated 5V and 3.3V from single Li-ion cell. IC Role / Device Role / Timing Role: Primary DC/DC controller delivering up to 5A peak to analog front-end and microcontroller; supports cold-temperature operation down to –40°C. Use Value: ±2% output accuracy ensures sensor ADC reference stability; 100% duty cycle sustains operation as battery discharges to 2.8V. |
| Wireless Modems | Industrial Handheld Scanners |
Use Scenario: LTE Cat-M1/NB-IoT modules in asset trackers operating for years on primary lithium batteries. IC Role / Device Role / Timing Role: High-efficiency buck controller powering baseband SoC and RF transceiver; cycles between active bursts and deep sleep. Use Value: 2µA shutdown current minimizes self-discharge; programmable soft-start prevents brownout during wake-up; robust against voltage transients on shared battery rail. | Use Scenario: Rugged barcode scanners powered by removable Li-ion packs, requiring reliable 5V for laser diode and imager. IC Role / Device Role / Timing Role: Main power controller handling 0–3A pulsed loads during scan events; withstands repeated hot-plug and reverse-polarity exposure. Use Value: Short-circuit protection prevents field failures from ESD-induced diode failure; wide VIN range accommodates charger input surges up to 20V. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM5116MH/NOPB | Current-mode synchronous buck controller; supports N-channel high-side MOSFET; higher IQ (2.5mA active); requires external bootstrap capacitor. | Targets higher-power (>10A), higher-VIN (6–100V) industrial supplies; lacks Burst Mode™ for ultra-low-IQ operation. | Choose LM5116MH/NOPB when designing for >12V input or synchronous rectification; avoid for battery life-critical sub-100µA standby. |
| TPS40210DGQR | Voltage-mode controller; 2.5–5.5V UVLO; no integrated 1.23V reference; requires external error amp and reference; IQ = 1.5mA. | Designed for isolated flyback and forward converters; not optimized for simple buck topologies or low-IQ portable use. | Choose TPS40210DGQR only for non-battery, isolated power architectures; unsuitable as direct functional replacement for LTC1771IS8#TRPBF. |
Compared with LM5116MH/NOPB and TPS40210DGQR, the LTC1771IS8#TRPBF delivers uniquely low 10µA no-load current, integrated 1.23V reference, and seamless Burst Mode™ transition-making it irreplaceable in multi-year battery applications where every microamp counts.
Availability
LTC1771IS8#TRPBF is available at Aetrix Electronics and suitable for cellular telephones, portable medical instruments, and industrial handheld scanners requiring stable component supply with guaranteed long-term availability and full traceability.
Supply support for LTC1771IS8#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 all Linear-branded parts including the LTC1771IS8#TRPBF.
The LTC1771IS8#TRPBF belongs to Linear's legacy high-efficiency DC/DC controller family, designed specifically for battery-powered portable electronics demanding ultralow quiescent current, wide input range, and robust transient response without sacrificing small size.
FAQ
What is the maximum output current supported by the LTC1771IS8#TRPBF?
The LTC1771IS8#TRPBF is a controller-not a converter-and supports up to 5A output current depending on external component selection: P-MOSFET RDS(ON), inductor saturation current, RSENSE value (100mV/IMAX rule), and thermal layout. At 5A, proper heatsinking of the MSOP-8 package and low-ESR output capacitors are essential to maintain regulation and reliability.
Does the LTC1771IS8#TRPBF require an external compensation network?
Yes, the LTC1771IS8#TRPBF uses OPTI-LOOP™ architecture on the ITH pin, requiring an external RC network (typically 1–10nF capacitor + 10–100kΩ resistor) between ITH and GND for loop stability. Unlike voltage-mode controllers, this single-pole compensation simplifies design and maintains stability across varied output capacitor ESR and capacitance values.
How does Burst Mode™ operation affect output voltage ripple on the LTC1771IS8#TRPBF?
Burst Mode™ on the LTC1771IS8#TRPBF increases low-frequency ripple (tens to hundreds of Hz) due to intermittent switching bursts, but minimizes high-frequency noise. Adding a 5pF feedforward capacitor across the upper feedback resistor (R2) suppresses this ripple. Disabling Burst Mode™ via the MODE pin restores continuous switching and eliminates burst-related ripple at the cost of reduced light-load efficiency.
Can the LTC1771IS8#TRPBF operate with a 2.5V input supply?
No-the LTC1771IS8#TRPBF has a minimum input voltage of 2.8V per Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 2.8V risks improper gate drive, unstable regulation, or failure to start. For sub-2.8V battery applications, consider the LTC3642 or LTC3639, which support down to 2.2V.
What is the purpose of the SENSE pin on the LTC1771IS8#TRPBF?
The SENSE pin on the LTC1771IS8#TRPBF monitors the voltage drop across an external current-sense resistor (RSENSE) connected between VIN and the source of the external P-MOSFET. It sets both the peak switch current limit (110–140mV threshold) and the Burst Mode™ entry point, enabling accurate current limiting and adaptive light-load efficiency optimization.
LTC1771IS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (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:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 2.8V ~ 18V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Enable, Soft Start
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1771IS8#TRPBF FAQ
1.How can I place an order for LTC1771IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1771IS8#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 LTC1771IS8#TRPBF reliable?
The price and inventory of LTC1771IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1771IS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1771IS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1771IS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1771IS8#TRPBF?
LTC1771IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1771IS8#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 LTC1771IS8#TRPBF?
For technical support, including LTC1771IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1771IS8#TRPBF requirements.
6.How does Aetrix verify that LTC1771IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1771IS8#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 LTC1771IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1771IS8#TRPBF?
All LTC1771IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1771IS8#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 LTC1771IS8#TRPBF part is unused and in its original packaging.
Return procedure for LTC1771IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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