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Analog Devices Inc. LT1949ES8#TRPBF
- Part No.:
- LT1949ES8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1949ES8#TRPBF.pdf
- Description:
- IC REG BOOST SEPIC ADJ 1A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,956
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Product details
Overview
LT1949ES8#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency current-mode step-up DC/DC converter IC with an integrated 1A, 0.5Ω NPN switch, 600kHz switching frequency, 1.24V feedback reference, and active low-battery detector. It generates 10V at 175mA from a 3.3V input and is designed for LCD bias supplies in portable electronics.
For engineers reviewing the LT1949ES8#TRPBF datasheet, LT1949ES8#TRPBF pinout, LT1949ES8#TRPBF application, or LT1949ES8#TRPBF equivalent, key selection criteria include its 1.5V minimum input voltage, 30V switch rating, 410mV VCE(SAT) at 800mA, shutdown quiescent current of 25µA, and external compensation flexibility for ceramic output capacitors.
Technical Context
The LT1949ES8#TRPBF employs current-mode control with a built-in ramp generator to prevent subharmonic oscillation above 50% duty cycle. Its error amplifier features 70–240 µmhos transconductance and 700 V/V voltage gain, driven by an external RC network on the VC pin for loop stabilization.
It integrates a precision 200mV low-battery reference with ±5% tolerance, LBI input bias current ≤60nA, and open-collector LBO output capable of sinking 10µA. The SHDN pin operates with logic-level thresholds (0.4V low, 1.4V high) and draws ≤0.1µA when enabled.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Rating | 30V max SW voltage - supports up to 28V output with single-inductor boost topology |
| Feedback Voltage | 1.24V ±20mV - sets output via resistor divider: VOUT = 1.24V × (1 + R1/R2) |
| Switch VCE(SAT) | 410mV at 800mA - enables high efficiency at medium load; reduces conduction loss |
| Quiescent Current | 4.5mA typical operating / 25µA shutdown - preserves battery life in portable systems |
| Low-Battery Threshold | 200mV ±10mV on LBI pin - allows precise battery monitoring down to ~1.5V cell voltage |
| Switching Frequency | 600kHz fixed - enables compact magnetics and low-output-ripple filtering |
| Input Voltage Range | 1.5V to 12V - supports single-cell Li-ion, multi-cell alkaline, and USB-powered operation |
Pinout & Package
LT1949ES8#TRPBF is housed in an 8-lead plastic SO (Small Outline) package, 0.150" wide, with standard JEDEC MS-012AC footprint and θJA = 120°C/W thermal resistance.
| 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; internal 1.24V reference determines regulated output voltage |
| SHDN (Pin 3) | Enable/disable control | Logic-level input: <0.4V disables (only LBD active); >1.4V enables; draws <0.1µA when high |
| GND (Pin 4) | Power ground | Primary return path for switch, error amp, and LBD; must tie directly to local ground plane |
| SW (Pin 5) | Switch collector | Drives external inductor/diode; handles peak currents up to 1.5A; minimize trace area for EMI control |
| VIN (Pin 6) | Input supply | Accepts 1.5–12V; requires local 22µF ceramic bypass capacitor placed within 5mm |
| LBI (Pin 7) | Low-battery input | High-impedance input referenced to 200mV; bias current flows out (≤60nA), enabling resistive divider sensing |
| LBO (Pin 8) | Low-battery output | Open-collector NPN output; sinks 10µA max; requires external 1MΩ pull-up for processor interrupt signaling |
Key Features
| Feature | Design Value |
|---|---|
| Integrated 1A NPN switch | Eliminates external transistor and drive circuitry; reduces BOM count and layout complexity |
| Active low-battery detector | Remains functional during shutdown - enables battery monitoring without system wake-up |
| External VC compensation | Allows optimization for low-ESR ceramic capacitors (e.g., 10µF X5R), reducing output ripple and size |
| 1.5V minimum input voltage | Supports deep discharge of single Li-ion or two alkaline cells - extends usable battery capacity |
| 600kHz fixed-frequency PWM | Enables use of small 10µH inductors and avoids audible noise; simplifies EMI filter design |
Applications
| Portable LCD Bias Supply | GPS Receiver Power |
|---|---|
|
Use Scenario: Generating +10V and –8V bias rails for TFT-LCD source/gate drivers in handheld medical monitors. IC Role / Device Role / Timing Role: Primary boost converter providing stable 10V/175mA output; LBO signals battery depletion to MCU before display flicker occurs. Use Value: Enables single-cell Li-ion operation with no external switch or compensation components beyond R/C network. |
Use Scenario: Powering GPS front-end LNA and baseband ICs requiring clean 3.3V from a 2.7–4.2V Li-ion battery. IC Role / Device Role / Timing Role: Boost regulator delivering 3.3V at 200mA; fixed 600kHz frequency avoids interference with GPS L1 band (1.575GHz). Use Value: Low 25µA shutdown current extends standby time; 1.5V start-up supports battery recovery after deep discharge. |
| Battery-Backed Diagnostic Instrument | Handheld Ultrasound Probe Interface |
|
Use Scenario: Maintaining real-time clock and SRAM backup during main power loss in portable ECG devices. IC Role / Device Role / Timing Role: Secondary boost stage generating 5V from depleted 2.2V backup coin cell; LBI monitors cell voltage continuously. Use Value: 200mV LBI threshold ensures accurate end-of-life detection; 410mV VCE(SAT) minimizes dropout at low input. |
Use Scenario: Supplying 8V bias to piezoelectric transducer driver ICs in battery-powered ultrasound wands. IC Role / Device Role / Timing Role: High-efficiency boost converter delivering 8V/200mA; VC pin allows tuning for transient response during pulse-echo bursts. Use Value: Current-mode control provides fast load-step response (<50µs settling); 30V switch rating accommodates flyback margin. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1317BEMS8#TRPBF | Pin-for-pin compatible; lower 600mA switch current limit; 1.25V FB reference; no LBI/LBO pins | Lacks low-battery monitoring; limited to ≤100mA output at 10V; unsuitable where battery state awareness is required | Select LT1317B only if cost sensitivity outweighs need for LBD and higher output current |
| LT3467ES6#TRPBF | Higher 1.3A switch; 1.23V FB; integrated soft-start; no LBI/LBO; SOT-23-6 package | Smaller footprint but no battery monitoring; requires different compensation; not pin-compatible | Choose LT3467 for space-constrained designs needing >175mA at 10V, accepting trade-off of missing LBD functionality |
Compared with LT1317B and LT3467, the LT1949ES8#TRPBF uniquely combines 1A switching capability, integrated low-battery detection with shutdown persistence, and SO-8 packaging - making it optimal for battery-critical LCD and portable instrumentation where both power and state monitoring are essential.
Availability
LT1949ES8#TRPBF is available at Aetrix Electronics and suitable for portable medical monitors, GPS receivers, and handheld diagnostic instruments requiring stable component supply, long-term lifecycle support, and guaranteed performance across –40°C to 85°C.
Supply support for LT1949ES8#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 continuity, technical documentation, and manufacturing for legacy Linear parts including the LT1949 series.
The LT1949ES8#TRPBF belongs to Linear's precision DC/DC converter family, engineered specifically for low-noise, battery-sensitive applications such as LCD bias generation and portable instrumentation where input voltage range, shutdown IQ, and integrated monitoring are critical.
FAQ
What is the minimum input voltage required for LT1949ES8#TRPBF to start switching?
The LT1949ES8#TRPBF starts switching at VIN ≥ 1.5V. This enables operation from deeply discharged single-cell Li-ion batteries or two-series alkaline cells. Startup behavior is verified across temperature; the device sustains regulation down to 1.7V under load per Electrical Characteristics table. Below 1.5V, the internal bias circuitry cannot activate the oscillator or error amplifier.
Can LT1949ES8#TRPBF be used in SEPIC topology, and what modifications are needed?
Yes, LT1949ES8#TRPBF supports SEPIC configuration, as confirmed in Typical Application TA02 (4-cell to 5V SEPIC). Required changes include adding a second coupled inductor (L2), repositioning D1 as a common cathode diode, and adjusting R1/R2 for 5V feedback. The VC pin compensation network must be retuned - typical values shift to 1MΩ + 3.3nF - due to altered loop dynamics and dual-inductor coupling effects.
How does the low-battery detector behave during LT1949ES8#TRPBF shutdown mode?
During shutdown (SHDN pin < 0.4V), the LT1949ES8#TRPBF disables the main switching regulator and error amplifier but keeps the low-battery detector fully active. The 200mV internal reference, LBI comparator, and open-collector LBO output remain powered. LBO pulls low when VLBI drops below 200mV ±10mV, allowing host microcontrollers to monitor battery state without waking the main system.
What is the maximum output voltage achievable with LT1949ES8#TRPBF using a single inductor?
The LT1949ES8#TRPBF supports up to 28V output with a single inductor, constrained by its 30V absolute maximum SW pin voltage rating and internal switch breakdown margin. At 28V output, minimum input must be ≥2.5V to maintain stable regulation, and external diode (e.g., MBRM120LT3) and capacitor voltage ratings must be ≥35V. Efficiency drops to ~72% at 28V/50mA (VIN = 3.3V) per characterization data.
Is LT1949ES8#TRPBF RoHS compliant and lead-free?
Yes, LT1949ES8#TRPBF is RoHS compliant and lead-free. The "#TRPBF" suffix explicitly denotes lead-free, RoHS-compliant packaging per Analog Devices' product marking convention. The SO-8 package uses matte tin (Sn) lead finish, and all die attach, mold compound, and wire bond materials meet EU Directive 2011/65/EU requirements. Full compliance documentation is available in ADI's PCN #17-0122.
LT1949ES8#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:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1949ES8#TRPBF FAQ
1.How can I place an order for LT1949ES8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1949ES8#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 LT1949ES8#TRPBF reliable?
The price and inventory of LT1949ES8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1949ES8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1949ES8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1949ES8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1949ES8#TRPBF?
LT1949ES8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1949ES8#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 LT1949ES8#TRPBF?
For technical support, including LT1949ES8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1949ES8#TRPBF requirements.
6.How does Aetrix verify that LT1949ES8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1949ES8#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 LT1949ES8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1949ES8#TRPBF?
All LT1949ES8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1949ES8#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 LT1949ES8#TRPBF part is unused and in its original packaging.
Return procedure for LT1949ES8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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