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Analog Devices Inc. LTC1771ES8#PBF
- Part No.:
- LTC1771ES8#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1771ES8#PBF.pdf
- Description:
- IC REG CTRLR BUCK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:100
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Product details
Overview
LTC1771ES8#PBF from Analog Devices (formerly Linear Technology) is a high-efficiency, current-mode step-down DC/DC controller driving an external P-channel MOSFET. It delivers up to 5A output current, operates from 2.8V to 20V input, regulates output from 1.23V to 18V, achieves >93% efficiency, and draws only 10µA quiescent current at no load - ideal for battery-powered portable instrumentation and lithium-ion-powered wireless modems.
For engineers reviewing the LTC1771ES8#PBF datasheet, LTC1771ES8#PBF pinout, LTC1771ES8#PBF application, or LTC1771ES8#PBF equivalent, key selection considerations include its constant off-time architecture, 3.5µs minimum off-time, ±2% VFB accuracy, 100% duty cycle capability for ultra-low dropout, and Burst Mode™ operation enabling sub-10µA no-load supply current in portable power systems.
Technical Context
The LTC1771ES8#PBF implements a constant off-time, current-mode control architecture with a fixed 3.5µs off-time that extends up to 70µs under low-VFB conditions (e.g., short-circuit), ensuring safe inductor current decay. Its error amplifier output (ITH pin) directly programs peak inductor current via an external sense resistor, enabling precise current limiting and stable soft-start ramping.
It features dual operating modes: Burst Mode™ (enabled by MODE pin ≥2V) reduces no-load IQ to 9µA while maintaining regulation via intermittent switching bursts, and forced continuous mode (MODE = GND) disables bursting for low-noise output at light loads. The RUN/SS pin integrates shutdown control and programmable soft-start via external capacitor CSS.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2.8V to 20V - supports single-to-4-cell Li-ion batteries and wide industrial input rails without external LDO pre-regulation. |
| Output Voltage Range | 1.23V to 18V - set via external resistive divider; 1.23V internal reference enables precise adjustable regulation. |
| No-Load Supply Current | 10µA - enables multi-week battery life in always-on portable instruments with minimal standby drain. |
| Shutdown Current | 2µA - ensures near-zero system leakage during deep sleep or transport storage. |
| Feedback Voltage Accuracy | ±2% over –40°C to 85°C - guarantees stable output voltage across temperature without calibration. |
| Current Sense Threshold | 110mV to 180mV - sets peak switch current with ±30mV tolerance; determines maximum output current via RSENSE. |
| Off-Time Duration | 3.5µs (nominal), up to 70µs - provides robust short-circuit protection and maintains stability under low-VOUT or dropout conditions. |
| Efficiency Peak | >93% - achieved at mid-load (e.g., 1A–2A) with optimized MOSFET and diode selection; critical for thermal management in sealed enclosures. |
Pinout & Package
The LTC1771ES8#PBF is housed in an 8-lead MSOP package (3mm × 3mm, 0.65mm pitch), optimized for compact battery-powered designs requiring minimal PCB area and thermal resistance (θJA = 200°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| RUN/SS (Pin 1) | Run enable / Soft-start control | Pull low to shut down (IQ < 2µA); connect external capacitor for linear soft-start ramp and inrush current limiting. |
| ITH (Pin 2) | Error amplifier output / Current limit programming | Voltage controls peak inductor current; clamped at ~1V in Burst Mode sleep; used for OPTI-LOOP™ compensation. |
| VFB (Pin 3) | Feedback input | Compares divided output voltage against 1.23V internal reference; ±2% accuracy ensures tight regulation. |
| GND (Pin 4) | Analog and power ground | Common return for feedback, sense, and gate drive circuits; requires low-impedance connection to minimize noise coupling. |
| PGATE (Pin 5) | P-channel MOSFET gate driver output | High-current (1A peak) driver swinging from GND to VIN; drives external high-side switch with fast 70ns rise/fall times. |
| VIN (Pin 6) | Main power input | Supplies internal circuitry and PGATE driver; accepts 2.8V–20V; must be decoupled with low-ESR ceramic capacitor. |
| SENSE (Pin 7) | Current sense input | Monitors voltage drop across external RSENSE to detect peak switch current; sets current limit and Burst Mode threshold. |
| MODE (Pin 8) | Burst Mode enable/disable | Connect to VIN (≥2V) to enable ultralow-IQ Burst Mode; tie to GND to force continuous conduction for low-noise operation. |
Key Features
| Feature | Design Value |
|---|---|
| Constant off-time current mode control | Enables excellent line/load transient response and inherent short-circuit protection without slope compensation. |
| 100% duty cycle operation | Supports ultra-low dropout regulation (e.g., 5V→4.8V), extending usable battery voltage range in Li-ion systems. |
| Defeatable Burst Mode™ | Reduces no-load IQ to 9µA while maintaining regulation; disable via MODE pin for EMI-sensitive applications. |
| Programmable soft-start | Prevents input surge current and output overshoot using external capacitor on RUN/SS pin with linear ITH ramp. |
| Short-circuit protected | Automatic foldback via SENSE pin monitoring; limits peak current during fault and prevents thermal runaway. |
| Micropower shutdown | Reduces total system IQ to 2µA - critical for long-term storage or emergency backup power states. |
Applications
| Cellular Telephones | Portable Instruments |
|---|---|
Use Scenario: Power management in GSM/UMTS handsets with dual Li-ion cells (7.2V–8.4V nominal) supplying 3.3V logic and RF sections. IC Role / Device Role / Timing Role: Step-down controller regulating core voltage from battery; manages dynamic load steps during transmit bursts. Use Value: 10µA quiescent current extends talk time; Burst Mode maintains regulation during idle without compromising sleep current budget. |
Use Scenario: Battery-powered handheld multimeter or oscilloscope with 3.3V microcontroller, analog front-end, and LCD display. IC Role / Device Role / Timing Role: Primary DC/DC controller converting 9V alkaline or 7.4V Li-ion to stable 3.3V rail with low noise and high PSRR. Use Value: 93% peak efficiency minimizes heat in sealed plastic enclosure; 100% duty cycle sustains operation down to 2.8V battery cutoff. |
| Wireless Modems | Battery Chargers |
Use Scenario: LTE or NB-IoT modem module powered by single Li-ion cell (3.0V–4.2V), requiring regulated 3.3V for baseband IC and 5V for USB interface. IC Role / Device Role / Timing Role: High-efficiency buck controller for main 3.3V rail; paired with charge pump or second stage for 5V generation. Use Value: Wide 2.8V–20V input accommodates charger adapter input and battery-only operation; ±2% VFB ensures ADC reference stability. |
Use Scenario: Smart battery charger for 2S/3S Li-ion packs, where LTC1771ES8#PBF supplies auxiliary 3.3V rail for fuel gauge MCU and communication interface. IC Role / Device Role / Timing Role: Secondary regulator deriving clean 3.3V from main charging rail (e.g., 12V or 19V adapter), independent of battery state. Use Value: 20V absolute max input withstands transient spikes on unregulated adapters; short-circuit protection isolates fault from charging circuitry. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3502AEDD#PBF | Fixed 3.3V output, integrated 1.5A switch, no external MOSFET required; higher no-load IQ (25µA) but simpler BOM. | Suitable for space-constrained designs where 3.3V fixed output suffices and 5A current is unnecessary. | Select LT3502AEDD#PBF when board area and component count outweigh need for adjustable VOUT and 5A scalability. |
| TPS54202DDCR | Integrated 2A synchronous buck; 2.5µA shutdown IQ; requires external compensation; lower max input (17V vs 20V). | Better for cost-sensitive, medium-current (≤2A) applications needing lowest possible footprint and no external FET layout. | Choose TPS54202DDCR if 2A output and 17V input ceiling are acceptable, and synchronous rectification is preferred over discrete P-FET + Schottky. |
Compared with LT3502AEDD#PBF and TPS54202DDCR, the LTC1771ES8#PBF uniquely supports 5A output via external P-MOSFET, 20V input, and 10µA no-load IQ - making it optimal for high-flexibility, high-efficiency, battery-life-critical designs where external component control is acceptable.
Availability
LTC1771ES8#PBF is available at Aetrix Electronics and suitable for cellular telephones, portable instruments, wireless modems, battery chargers, and scanners requiring stable component supply with guaranteed long-term manufacturability and consistent parametric performance.
Supply support for LTC1771ES8#PBF 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, datasheets, and application engineering for legacy Linear parts including the LTC1771ES8#PBF.
The LTC1771ES8#PBF belongs to Linear's high-efficiency DC/DC controller family, designed specifically for battery-powered portable equipment where ultralow quiescent current, wide input range, and flexible external FET control are essential.
FAQ
What is the maximum output current supported by the LTC1771ES8#PBF?
The LTC1771ES8#PBF is a controller-not a converter-and supports up to 5A output current when paired with an appropriately rated external P-channel MOSFET, sense resistor, inductor, and catch diode. Actual achievable current depends on thermal design, input/output voltage differential, and component selection per the datasheet's RSENSE and inductor sizing guidelines. The LTC1771ES8#PBF itself does not limit current; it programs peak switch current via the SENSE pin voltage.
Does the LTC1771ES8#PBF require an external catch diode?
Yes, the LTC1771ES8#PBF requires an external catch diode because it drives only a high-side P-channel MOSFET and lacks synchronous rectification. A Schottky diode (e.g., UPS5817) is recommended for low forward voltage and minimal reverse leakage to preserve no-load efficiency. The diode conducts during the MOSFET's off-time and must handle peak inductor current at near-100% duty cycle under short-circuit conditions. The LTC1771ES8#PBF does not integrate or drive a second switch.
How does Burst Mode™ operation affect noise and efficiency in the LTC1771ES8#PBF?
Burst Mode™ operation in the LTC1771ES8#PBF improves light-load efficiency by disabling switching until output voltage droop triggers a short burst of cycles, reducing average supply current to ~9µA. However, this causes variable-frequency operation and increased output voltage ripple. Disabling Burst Mode via the MODE pin forces continuous switching for low-noise, fixed-frequency output - at the cost of higher light-load IQ (~150µA). The LTC1771ES8#PBF allows engineers to trade off EMI compliance versus battery runtime based on actual load profile.
Can the LTC1771ES8#PBF operate with a 2.5V input supply?
No, the LTC1771ES8#PBF has a minimum input voltage of 2.8V per its Absolute Maximum Ratings and Electrical Characteristics tables. Operation below 2.8V is not specified or guaranteed; attempting to power the LTC1771ES8#PBF at 2.5V may result in failure to start, unstable regulation, or undefined behavior. For sub-2.8V inputs, consider alternative controllers such as the LTC3642 or boost-buck architectures.
What is the purpose of the RC network on the ITH pin in LTC1771ES8#PBF designs?
The RC network (typically 10kΩ + 22pF) on the ITH pin of the LTC1771ES8#PBF implements OPTI-LOOP™ compensation, stabilizing the current-mode control loop across varying output capacitance and ESR. It sets dominant pole and zero locations to ensure phase margin >45° under all load and component conditions. This network directly affects transient response and is critical for maintaining regulation during rapid load steps - especially with low-ESR ceramic output capacitors. The LTC1771ES8#PBF's ITH pin is the sole point for loop compensation.
LTC1771ES8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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
LTC1771ES8#PBF FAQ
1.How can I place an order for LTC1771ES8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1771ES8#PBF 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 LTC1771ES8#PBF reliable?
The price and inventory of LTC1771ES8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1771ES8#PBF is usually 5 days.
3.What payment methods are accepted for LTC1771ES8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1771ES8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1771ES8#PBF?
LTC1771ES8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1771ES8#PBF 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 LTC1771ES8#PBF?
For technical support, including LTC1771ES8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1771ES8#PBF requirements.
6.How does Aetrix verify that LTC1771ES8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1771ES8#PBF 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 LTC1771ES8#PBF meets industry standards.
7.What is the process for return or replacement of LTC1771ES8#PBF?
All LTC1771ES8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1771ES8#PBF, 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 LTC1771ES8#PBF part is unused and in its original packaging.
Return procedure for LTC1771ES8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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