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Analog Devices Inc. LT1949IS8#TRPBF
- Part No.:
- LT1949IS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1949IS8#TRPBF.pdf
- Description:
- IC REG BOOST SEPIC ADJ 1A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,267
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Product details
Overview
LT1949IS8#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency current-mode step-up DC/DC converter with a 1A, 0.5Ω internal NPN switch, generating 10V at 175mA from 3.3V input. It features 600kHz switching, 1.24V feedback reference, and integrated low-battery detector active in shutdown-designed for LCD bias supplies in portable instrumentation.
For engineers reviewing the LT1949IS8#TRPBF datasheet, LT1949IS8#TRPBF pinout, LT1949IS8#TRPBF application, or LT1949IS8#TRPBF equivalent, key selection criteria include its 1.5V–12V input range, 30V switch rating, VC compensation flexibility, LBO open-collector output, and –40°C to 85°C industrial temperature grade.
Technical Context
The LT1949IS8#TRPBF employs peak-current-mode control with a 600kHz oscillator and internal ramp compensation to prevent subharmonic oscillation above 50% duty cycle. Its error amplifier (gm = 70–240 µmhos, AV = 700 V/V) drives the VC pin to regulate output via external RC compensation, enabling stable operation with low-ESR ceramic capacitors.
It integrates a precision 200mV low-battery detector with ±5% threshold accuracy and 2000 V/V gain, maintaining functionality during shutdown (25µA IQ). The SHDN pin accepts logic-level enable (1.4V high, 0.4V low), while SW pin supports up to 30V swing and 1.13A typical switch current limit at 30% duty cycle.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 30V max SW voltage - enables up to 28V output using single inductor |
| Feedback Voltage | 1.24V ±20mV - sets output via R1/R2 divider: VOUT = 1.24V × (1 + R1/R2) |
| Switch Current Limit | 1.13A typ at 30% duty - ensures safe 1A continuous operation with margin |
| Quiescent Current | 4.5mA typ operating / 25µA typ shutdown - minimizes battery drain in portable use |
| Low-Battery Threshold | 200mV ±10mV - precise trip point for LBI input, active even in shutdown mode |
| VC Transconductance | 70–240 µmhos - determines compensation network sensitivity and loop stability |
| Operating Temp Range | –40°C to +85°C - qualified for industrial embedded and medical instrumentation |
Pinout & Package
LT1949IS8#TRPBF is housed in an 8-lead plastic SO (Small Outline) package, 0.150" wide, with standard SO8 footprint and 1.27mm pitch. Thermal resistance θJA = 120°C/W; maximum junction temperature = 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC (Pin 1) | Compensation node | Connects external RC network (e.g., 68kΩ + 330pF) to ground for loop stability with ceramic output caps |
| FB (Pin 2) | Feedback input | Senses resistor divider tap; 1.24V reference sets regulated output voltage |
| SHDN (Pin 3) | Enable/disable control | Pull ≤0.4V for shutdown (LBO remains active); ≥1.4V to enable; logic-compatible input |
| GND (Pin 4) | Power ground | Primary return path; must tie directly to local ground plane at single point to avoid dI/dt noise coupling |
| SW (Pin 5) | Switch collector | Connects to inductor/diode; handles high-speed 1A switching; requires minimized trace area for EMI control |
| VIN (Pin 6) | Input supply | 1.5V–12V input; must be bypassed with low-ESR capacitor placed ≤5mm from pin |
| LBI (Pin 7) | Low-battery detector input | Accepts scaled battery voltage; internal 200mV reference compares against LBI to trigger LBO |
| LBO (Pin 8) | Low-battery output | Open-collector NPN output; sinks 10µA; requires external 1MΩ pull-up for processor interface |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 600kHz switching | Enables compact LC filter design with predictable EMI profile and easy noise filtering |
| Internal 1A, 0.5Ω NPN switch | Eliminates external transistor; delivers 175mA at 10V from 3.3V with minimal conduction loss |
| VC pin for external compensation | Allows optimization for ceramic output capacitors and varying load dynamics without redesign |
| Low-battery detector active in shutdown | Permits system-level battery monitoring during sleep modes without auxiliary circuitry |
| 1.24V precision feedback reference | Ensures tight output regulation across temperature and line/load variations |
Applications
| Large-Screen LCD Bias Supply | Portable GPS Receiver Power |
|---|---|
Use Scenario: Generating +10V and –8V bias rails for TFT-LCD source/gate drivers in handheld diagnostic devices. IC Role / Device Role / Timing Role: Primary boost converter providing regulated positive output; paired with external charge pump or inverting stage for negative rail. Use Value: Delivers stable 175mA at 10V from 3.3V battery input while maintaining <50mV load regulation and low-noise 600kHz operation compatible with sensitive analog front-ends. | Use Scenario: Powering GPS RF frontend and baseband ICs in battery-operated asset trackers with cold-start requirements. IC Role / Device Role / Timing Role: Step-up regulator supplying 3.3V or 5V system rail from single Li-ion cell; LBO monitors battery health during deep-sleep intervals. Use Value: Operates down to 1.5V input, enabling extended runtime; 25µA shutdown current preserves battery life; LBO's 200mV threshold ensures accurate end-of-life detection before brownout. |
| Battery-Backed Medical Sensor Node | Industrial Handheld Test Equipment |
Use Scenario: Providing backup power and status monitoring for ECG sensor nodes during main supply interruption. IC Role / Device Role / Timing Role: Dual-role device: DC/DC converter for bias generation and autonomous low-voltage supervisor via LBI/LBO pins. Use Value: Maintains LBO alert functionality during shutdown, allowing microcontroller wake-on-low-battery without waking main regulator-reducing average system power by >90%. | Use Scenario: Supplying isolated analog signal chain rails (+15V, –15V) in portable multimeters and oscilloscopes. IC Role / Device Role / Timing Role: High-efficiency boost stage feeding external inverting or SEPIC topology for dual-rail generation. Use Value: 30V switch rating supports 28V outputs; 600kHz frequency allows small 10µH inductors; SO-8 package fits constrained board space in ruggedized enclosures. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar step-up DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1317BEMS8#TRPBF | Same pinout, 600kHz, but lower 600mA switch current and 20V switch rating | Rated for ≤100mA output; unsuitable for 175mA LCD bias loads | Select only for lower-current portable applications where size and IQ match are prioritized over output capability |
| LT3467EFE#TRPBF | Higher 2.5A switch, 40V rating, 1.2MHz switching, but requires external compensation and lacks integrated LBO | No built-in low-battery detector; needs external comparator and reference for battery monitoring | Choose when higher output current or faster transient response is required, accepting added component count for supervision |
Compared with LT1317BEMS8#TRPBF and LT3467EFE#TRPBF, the LT1949IS8#TRPBF uniquely balances 1A output capability, integrated LBO functionality, and SO-8 industrial temperature rating-making it optimal for space-constrained, battery-aware LCD and portable instrumentation designs where both power and supervision are co-integrated.
Availability
LT1949IS8#TRPBF is available at Aetrix Electronics and suitable for large-screen LCD bias supplies, portable GPS receivers, battery-backed medical sensors, industrial handheld test equipment, and diagnostic instrumentation requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1949IS8#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 legacy Linear parts including the LT1949 family.
The LT1949 belongs to Linear's high-efficiency, current-mode DC/DC converter product line, engineered specifically for portable and battery-powered systems needing compact, low-noise, and supervision-integrated boost solutions.
FAQ
What is the minimum input voltage supported by the LT1949IS8#TRPBF?
The LT1949IS8#TRPBF operates with input voltages as low as 1.5V, enabling compatibility with partially discharged single-cell Li-ion or multi-cell alkaline batteries. This specification is guaranteed across the full –40°C to +85°C industrial temperature range and allows the LT1949IS8#TRPBF to sustain regulation in brownout conditions where other converters would drop out.
How does the low-battery detector function in shutdown mode for the LT1949IS8#TRPBF?
The LT1949IS8#TRPBF's low-battery detector remains fully active during shutdown, drawing only 25µA total quiescent current. Its internal 200mV reference compares against the voltage applied to the LBI pin; when LBI falls below threshold, the open-collector LBO pin pulls low-allowing host microcontrollers to monitor battery state without powering the main converter. This behavior is confirmed in the Electrical Characteristics table and Figure 5 of the LT1949IS8#TRPBF datasheet.
What compensation network is recommended for ceramic output capacitors with the LT1949IS8#TRPBF?
A 68kΩ resistor in series with a 330pF capacitor connected between the VC pin and ground is the standard compensation network for ceramic output capacitors with the LT1949IS8#TRPBF. This combination stabilizes the current-mode loop across load and input variations, as validated in Typical Application Circuit 1 (Figure 1) and confirmed in the "VC (Pin 1)" functional description section of the LT1949IS8#TRPBF datasheet.
Is the LT1949IS8#TRPBF pin-compatible with any other Linear/Analog Devices boost converters?
Yes-the LT1949IS8#TRPBF is pin-for-pin compatible with the LT1317B in both MSOP and SO packages, sharing identical pin assignments for VIN, SW, FB, GND, SHDN, LBI, LBO, and VC. However, the LT1949IS8#TRPBF offers higher 1A switch current and 30V rating versus the LT1317B's 600mA and 20V limits, making direct substitution viable only when electrical margins are verified per application load.
What is the maximum output voltage achievable with the LT1949IS8#TRPBF?
The LT1949IS8#TRPBF supports output voltages up to 28V, limited by its 30V-rated internal switch and the breakdown voltage of external components (diode, capacitor, inductor). This is explicitly stated in the product description and reinforced by Absolute Maximum Ratings specifying SW voltage from –0.4V to +30V. Output voltage is set by the FB divider ratio, not by internal regulation limits.
LT1949IS8#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
- Function:
- Step-Up, Step-Up/Step-Down
- Output Configuration:
- Positive
- Topology:
- Boost, SEPIC
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.7V
- Voltage - Input (Max):
- 12V
- Voltage - Output (Min/Fixed):
- 1.7V
- Voltage - Output (Max):
- 28V
- Current - Output:
- 1A (Switch)
- Frequency - Switching:
- 600kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1949IS8#TRPBF FAQ
1.How can I place an order for LT1949IS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1949IS8#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 LT1949IS8#TRPBF reliable?
The price and inventory of LT1949IS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1949IS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1949IS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1949IS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1949IS8#TRPBF?
LT1949IS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1949IS8#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 LT1949IS8#TRPBF?
For technical support, including LT1949IS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1949IS8#TRPBF requirements.
6.How does Aetrix verify that LT1949IS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1949IS8#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 LT1949IS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1949IS8#TRPBF?
All LT1949IS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1949IS8#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 LT1949IS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1949IS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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