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Analog Devices Inc. LTC1147LIS8#TRPBF
- Part No.:
- LTC1147LIS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LTC1147LIS8#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,537
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Product details
Overview
LTC1147LIS8#TRPBF from Analog Devices (formerly Linear Technology) is a high-efficiency, constant off-time current-mode step-down switching regulator controller driving an external P-channel MOSFET. It operates from 3.5V to 16V input, delivers up to 2A output with 3.3V fixed regulation, achieves >95% efficiency at full load, maintains 160µA standby current in Burst Mode, and features micropower shutdown (<20µA). It is used in portable instrumentation and battery-powered digital systems requiring compact, high-efficiency DC/DC conversion.
For engineers reviewing the LTC1147LIS8#TRPBF datasheet, LTC1147LIS8#TRPBF pinout, LTC1147LIS8#TRPBF application, or LTC1147LIS8#TRPBF equivalent, key selection criteria include its 3.3V fixed output, 8-pin SOIC package, 160µA sleep-mode quiescent current, 25–150mV current-sense threshold range, and compatibility with external P-channel MOSFETs for low-dropout operation down to 100% duty cycle.
Technical Context
The LTC1147LIS8#TRPBF implements a constant off-time current-mode architecture with automatic Burst Mode™ operation to sustain high efficiency across three decades of load current (0mA–2A). Its timing capacitor (CT) at Pin 2 sets switching frequency, while internal gain block and voltage comparator regulate output via SENSE– (Pin 4) and SHDN/VFB (Pin 6) feedback.
It uses a built-in 1.25V reference and internal resistive divider to fix VOUT = 3.3V (±3.3% over temperature), supports logic-controlled shutdown with 0.5–2V threshold on Pin 6, and incorporates short-circuit protection by extending off-time during overload. The device requires no external compensation and enables low-noise, low-ripple operation with proper RSENSE and COUT ESR selection.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 3.3V ±3.3% (3.23V–3.43V) at 700mA load, enabling direct replacement of 3.3V LDOs with higher efficiency. |
| Input Voltage Range | 3.5V to 16V - supports single-cell Li-ion (4.2V), dual-cell NiMH (2.4–3.0V), and 5V/12V rail inputs without pre-regulation. |
| Quiescent Current | 160µA in Burst Mode - extends battery life in always-on portable devices with light-load operation. |
| Shutdown Current | <20µA - enables ultra-low-power system-level sleep states with full rail isolation. |
| Current Sense Threshold | 25mV to 150mV - sets peak inductor current via external RSENSE; allows precise IMAX tuning (e.g., 0.05Ω → ~3A peak). |
| Off-Time | 3.8–6.5µs (CT = 390pF) - determines minimum on-time and dropout behavior; scales inversely with VOUT to maintain regulation near VIN ≈ VOUT. |
| Package | 8-pin SOIC (S8) - industry-standard footprint compatible with automated assembly and thermal pad-less PCB layout. |
Pinout & Package
Package: 8-lead plastic SOIC (S8), θJA = 150°C/W, RoHS-compliant, tape-and-reel (TRPBF).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Main power input | Accepts 3.5V–16V supply; requires local 100µF + 1µF ceramic decoupling to minimize noise and transient voltage spikes. |
| CT (Pin 2) | Timing capacitor connection | Sets switching frequency via external capacitor; discharge current scales with VOUT to stabilize off-time across input range. |
| ITH (Pin 3) | Gain amplifier decoupling | Adjusts current comparator threshold dynamically; connects to 100kΩ resistor and 5pF capacitor for loop stability. |
| SENSE– (Pin 4) | Inverting current sense input | Connects to internal voltage divider; forms differential pair with SENSE+ to detect RSENSE voltage drop for current limiting. |
| SENSE+ (Pin 5) | Non-inverting current sense input | Paired with Pin 4; built-in 25mV offset enables accurate current trip detection independent of common-mode voltage. |
| SHDN/VFB (Pin 6) | Shutdown control / feedback | Logic-level input (0.5–2V threshold); grounded for normal operation; pulled high for micropower shutdown; not used as feedback in fixed-output LTC1147LIS8#TRPBF. |
| GND (Pin 7) | Power ground | Must be routed separately to COUT (–) and diode cathode to avoid ground bounce and current-loop interference. |
| PDRIVE (Pin 8) | P-channel MOSFET gate driver | High-current source/sink (VIN to GND swing); drives Si4431DY-class P-MOSFETs with <200ns transition times under 3nF load. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic Burst Mode™ operation | Maintains >85% efficiency down to 1mA load by disabling switching and reducing IQ to 160µA - eliminates light-load inefficiency cliffs. |
| Constant off-time current-mode control | Provides inherent line/load transient immunity and stable operation without external compensation components. |
| 100% duty-cycle low-dropout capability | Enables VOUT ≈ VIN regulation when input approaches output - critical for battery end-of-life operation. |
| Integrated short-circuit protection | Extends off-time during overload to limit average short-circuit current to ~IMAX - prevents thermal runaway without external circuitry. |
| Logic-compatible shutdown | Accepts standard CMOS signals (tr/tf < 1µs) on Pin 6 - simplifies integration with microcontroller GPIOs and PMIC sequencers. |
Applications
| Portable Medical Sensors | Industrial Handheld Terminals |
|---|---|
Use Scenario: Battery-powered glucose meter with real-time display, Bluetooth LE, and precision ADC requiring clean 3.3V rail. IC Role / Device Role / Timing Role: Step-down controller managing power delivery from 3.7V Li-ion cell to 3.3V system bus while minimizing self-heating during intermittent measurement bursts. Use Value: 160µA Burst Mode current extends 200mAh battery life to >12 months in standby; fixed 3.3V output eliminates need for external feedback resistors. | Use Scenario: Ruggedized warehouse scanner operating from 7.4V dual-cell Li-ion with barcode engine, imager, and Wi-Fi module. IC Role / Device Role / Timing Role: Primary DC/DC controller converting 7.4V–8.4V battery range to stable 3.3V for logic and RF sections, supporting rapid load transients during scan initiation. Use Value: Constant off-time architecture ensures <50µs recovery from 500mA load step; 100% duty cycle sustains operation until battery drops to 3.5V. |
| GPS Tracking Modules | Low-Power IoT Edge Nodes |
Use Scenario: Asset tracker using u-blox NEO-M8N GPS receiver and NB-IoT modem, powered by 3.6V primary lithium thionyl chloride cell. IC Role / Device Role / Timing Role: High-efficiency buck controller supplying regulated 3.3V only during periodic GPS fix acquisition and data transmission windows. Use Value: <20µA shutdown current preserves 19Ah cell capacity for >10-year deployment; Burst Mode eliminates switching noise during RF-sensitive GPS signal acquisition. | Use Scenario: Wireless sensor node with STM32L4 MCU, BME280 environmental sensor, and LoRa transceiver, harvesting energy from solar cell + supercapacitor. IC Role / Device Role / Timing Role: Input-wide (3.5V–16V) regulator managing variable solar input to deliver consistent 3.3V to mixed-signal SoC under partial-cloud conditions. Use Value: Wide VIN range accepts unregulated solar panel output (up to 16V open-circuit); low 160µA sleep IQ maximizes energy capture during low-light periods. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3631EMSE#TRPBF | Monolithic 3.3V buck converter (integrated MOSFET), 40V max VIN, 150mA output, no external RSENSE required. | Lower output current; suited for ultra-compact, low-IQ microcontroller rails - not for 2A loads. | Select LTC3631 if board space is constrained and load ≤150mA; LTC1147LIS8#TRPBF remains preferred for >1A applications with external MOSFET flexibility. |
| TPS54202DDCR | 2A integrated synchronous buck (no external diode), 3.5–28V VIN, adjustable output, 2.5µA shutdown IQ. | Requires external feedback resistors; lacks Burst Mode - efficiency drops sharply below 10mA. | Choose TPS54202 for higher VIN (>16V) or synchronous rectification needs; LTC1147LIS8#TRPBF offers superior light-load efficiency and P-MOSFET dropout advantage. |
Compared with LTC3631EMSE#TRPBF and TPS54202DDCR, the LTC1147LIS8#TRPBF provides higher output current headroom, true 100% duty cycle for ultra-low dropout, and proven Burst Mode efficiency below 1mA - making it optimal for battery-critical portable systems where external MOSFET control and minimal light-load IQ are essential.
Availability
LTC1147LIS8#TRPBF is available at Aetrix Electronics and suitable for portable instrumentation, battery-powered digital devices, and industrial handheld terminals requiring stable component supply with long-term lifecycle support.
Supply support for LTC1147LIS8#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. (ADI) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, formed through the acquisition of Linear Technology in 2017.
The LTC1147 series belongs to ADI's legacy high-efficiency DC/DC controller product line, designed specifically for battery-operated systems demanding micropower operation, wide input range, and robust transient response without complex compensation.
FAQ
What is the output voltage tolerance of the LTC1147LIS8#TRPBF over temperature and load?
The LTC1147LIS8#TRPBF delivers a fixed 3.3V output with ±3.3% tolerance (3.23V–3.43V) across –40°C to 85°C ambient temperature and 5mA–2A load range. This specification is guaranteed per the Electrical Characteristics table in the official datasheet, with typical regulation error of ±1% at 700mA load and VIN = 9V.
Can the LTC1147LIS8#TRPBF operate with input voltage below 3.5V?
No - the LTC1147LIS8#TRPBF has a minimum specified input voltage of 3.5V, as confirmed in the Absolute Maximum Ratings and Electrical Characteristics sections. Operation below this level is not characterized and may result in failure to start, unstable regulation, or undefined shutdown behavior. For sub-3.5V applications, consider the LTC1147LCS8-3.3 variant with extended low-VIN capability or alternative controllers like the LTC3631.
Does the LTC1147LIS8#TRPBF require external compensation components?
No - the LTC1147LIS8#TRPBF uses a constant off-time current-mode architecture that is inherently stable and does not require external compensation networks. The datasheet confirms that the Figure 1 reference design operates reliably with only the listed passive components (RSENSE, CT, L, CIN, COUT), eliminating loop compensation design effort and risk of instability.
What is the maximum continuous output current supported by the LTC1147LIS8#TRPBF?
The LTC1147LIS8#TRPBF itself does not deliver current directly; it controls an external P-channel MOSFET. With appropriate component selection (e.g., RSENSE = 0.05Ω, Si4431DY MOSFET, 50µH inductor), the reference design achieves 2A continuous output. Peak current capability depends on RSENSE value and MOSFET thermal limits - e.g., RSENSE = 0.02Ω enables ~3A peak before current-limit activation.
How does Burst Mode™ operation affect output ripple in the LTC1147LIS8#TRPBF?
In Burst Mode™, the LTC1147LIS8#TRPBF reduces switching frequency and enters sleep cycles, resulting in higher peak-to-peak output ripple - specified as 50mVP-P at ILOAD = 0A. This is intentional and acceptable for most low-power logic rails; however, sensitive analog circuits may require additional post-regulation filtering or forced continuous mode via external bias on ITH (Pin 3).
LTC1147LIS8#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):
- 3.5V ~ 14V
- Frequency - Switching:
- -
- Duty Cycle (Max):
- 100%
- Synchronous Rectifier:
- No
- Clock Sync:
- No
- Serial Interfaces:
- -
- Control Features:
- Current Limit, Enable
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LTC1147LIS8#TRPBF FAQ
1.How can I place an order for LTC1147LIS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1147LIS8#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 LTC1147LIS8#TRPBF reliable?
The price and inventory of LTC1147LIS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1147LIS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LTC1147LIS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1147LIS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1147LIS8#TRPBF?
LTC1147LIS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1147LIS8#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 LTC1147LIS8#TRPBF?
For technical support, including LTC1147LIS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1147LIS8#TRPBF requirements.
6.How does Aetrix verify that LTC1147LIS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LTC1147LIS8#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 LTC1147LIS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LTC1147LIS8#TRPBF?
All LTC1147LIS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1147LIS8#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 LTC1147LIS8#TRPBF part is unused and in its original packaging.
Return procedure for LTC1147LIS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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