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Analog Devices Inc. LT1949ES8#PBF
- Part No.:
- LT1949ES8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1949ES8#PBF.pdf
- Description:
- IC REG BOOST SEPIC ADJ 1A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:124
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Product details
Overview
LT1949ES8#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency current-mode step-up DC/DC converter with an integrated 1A, 0.5Ω NPN switch, 600kHz switching frequency, and 30V switch rating. It generates 10V at 175mA from a 3.3V input and features an external compensation pin (VC), low-battery detector (LBI/LBO), and shutdown control - ideal for LCD bias supplies in portable displays.
For engineers reviewing the LT1949ES8#PBF datasheet, LT1949ES8#PBF pinout, LT1949ES8#PBF application, or LT1949ES8#PBF equivalent, key selection criteria include its 1.24V feedback reference, 410mV VCE(SAT) at 800mA, 25µA shutdown quiescent current, and compatibility with ceramic output capacitors using 68kΩ/330pF VC network.
Technical Context
The LT1949ES8#PBF employs current-mode control with a built-in ramp generator to prevent subharmonic oscillation above 50% duty cycle. Its error amplifier (transconductance 70–240 µmhos, gain 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 dedicated low-battery detector with 200mV internal reference, active during shutdown, and uses logic-level SHDN (1.4V high, 0.4V low) to disable switching while retaining LBO functionality. The 30V-rated switch supports output voltages up to 28V with single-inductor topology.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 600 kHz fixed - enables compact LC filter design and low EMI with predictable noise spectrum. |
| Internal Switch | 1A, 0.5Ω NPN transistor rated to 30V - supports 10V/175mA boost from 3.3V with minimal conduction loss. |
| Feedback Reference | 1.24V ±2% - sets output voltage via resistor divider (VOUT = 1.24V × (1 + R1/R2)) with tight regulation. |
| VCE(SAT) | 410 mV at 800mA - ensures low dropout and high efficiency under full load, critical for battery-powered systems. |
| Quiescent Current | 4.5 mA operating / 25 µA shutdown - extends battery life in portable equipment with rapid enable/disable response. |
| Low-Battery Threshold | 200 mV ±10 mV on LBI pin - allows precise undervoltage detection independent of main regulator state. |
| Input Voltage Range | 1.5V to 12V - supports single-cell Li-ion, multi-cell alkaline, and wide-input industrial rails. |
Pinout & Package
LT1949ES8#PBF is housed in an 8-lead plastic SO (Small Outline) package (S8), 0.150" narrow body, with exposed pad not present. Pin spacing is 0.050" (1.27 mm) pitch; package outline conforms to JEDEC MS-012.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC (Pin 1) | Compensation node | Connects to series RC (e.g., 68kΩ + 330pF) to ground - sets loop stability and enables ceramic capacitor use. |
| FB (Pin 2) | Feedback input | Senses resistor divider tap; internal 1.24V reference regulates output voltage accurately. |
| SHDN (Pin 3) | Shutdown control | Logic-level input: <0.4V disables switching (25µA IQ); >1.4V enables operation. |
| GND (Pin 4) | Power ground | Main return path for switch, error amp, and LBO - must tie directly to local ground plane at single point. |
| SW (Pin 5) | Switch collector | Drives external inductor/diode; handles peak currents up to 1.5A with 30V max voltage swing. |
| VIN (Pin 6) | Input supply | Accepts 1.5–12V; requires local 22µF ceramic bypass (<5mm trace) for stable regulation. |
| LBI (Pin 7) | Low-battery input | High-impedance input referenced to 200mV - monitors battery voltage via resistive divider. |
| LBO (Pin 8) | Low-battery open-collector output | Sinks 10µA; requires external 1MΩ pull-up - signals battery fault even in shutdown mode. |
Key Features
| Feature | Design Value |
|---|---|
| Current-mode PWM control | Enables fast transient response and inherent cycle-by-cycle current limiting without external sensing. |
| External VC compensation | Allows optimization for ceramic output caps and varied load conditions - eliminates need for electrolytic bulk capacitance. |
| Active low-battery detector in shutdown | Maintains battery monitoring during system sleep - enables wake-on-low-voltage without auxiliary circuitry. |
| 1.5V minimum start-up voltage | Supports operation from nearly depleted single-cell batteries - extends usable runtime in portable devices. |
| 600kHz fixed oscillator | Reduces size of magnetics and filtering components while avoiding AM radio band interference. |
Applications
| Portable LCD Bias Supply | GPS Receiver Power |
|---|---|
|
Use Scenario: Generating +10V and –8V bias rails for TFT-LCD panels in handheld medical monitors and industrial HMIs. IC Role / Device Role / Timing Role: Primary boost converter providing regulated positive high-voltage rail; LBO triggers display dimming or alert before battery depletion. Use Value: Enables compact, low-noise bias generation using only one inductor and ceramic capacitors - reduces board area by >30% vs. legacy designs. |
Use Scenario: Powering GPS front-end LNA and RF ICs requiring stable 3.3V or 5V from a single 3.3V Li-ion cell. IC Role / Device Role / Timing Role: Step-up regulator maintaining constant output despite battery sag; SHDN synchronizes with GPS sleep cycles. Use Value: Delivers 175mA at 10V with 85% peak efficiency - extends tracking time between charges without thermal derating. |
| Battery Backup System | Diagnostic Medical Instrumentation |
|
Use Scenario: Maintaining real-time clock and SRAM retention during main power failure in smart meters and IoT gateways. IC Role / Device Role / Timing Role: Low-quiescent boost converter sourcing backup rail; LBI continuously monitors primary battery health. Use Value: 25µA shutdown current preserves backup battery for >5 years - meets IEC 62053-21 long-term retention requirements. |
Use Scenario: Providing isolated analog supply rails for precision ADC drivers and sensor signal chains in portable ultrasound probes. IC Role / Device Role / Timing Role: Low-noise, fixed-frequency boost stage feeding linear post-regulators - minimizes switching coupling into sensitive analog paths. Use Value: 600kHz operation allows simple LC filtering to achieve <10mVPP ripple - satisfies EN 60601-1 conducted emission limits. |
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#PBF | Same 8-pin MSOP footprint, 600kHz, but lower 600mA switch current and no LBI/LBO pins. | Lacks integrated low-battery monitoring - requires external comparator for battery-aware shutdown. | Choose when space-constrained layout prioritizes MSOP over SO and battery detection is handled externally. |
| LT3467EDD#TRPBF | Higher 2A switch, 1.3MHz switching, but no LBI/LBO and requires different compensation scheme. | Optimized for smaller inductors and faster transients - less suitable for low-noise LCD bias where 600kHz filtering is advantageous. | Prefer when higher output current (>200mA) or faster load steps dominate over battery monitoring and EMI constraints. |
Compared with LT1317BEMS8#PBF and LT3467EDD#TRPBF, the LT1949ES8#PBF uniquely combines 1A switching capability, integrated low-battery detection active in shutdown, and 600kHz fixed-frequency operation - making it the optimal choice for space- and battery-life-sensitive LCD bias and portable instrumentation where reliability under brownout is critical.
Availability
LT1949ES8#PBF is available at Aetrix Electronics and suitable for portable LCD bias supplies, GPS receiver power, and battery backup systems requiring stable component supply, long-lifecycle support, and traceable sourcing.
Supply support for LT1949ES8#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 technical and manufacturing continuity for all Linear ICs, including robust process control and military-grade screening options.
The LT1949ES8#PBF belongs to Linear's high-efficiency, low-quiescent-current DC/DC converter product line, designed specifically for portable and battery-critical applications demanding reliable voltage boosting with integrated system monitoring.
FAQ
What is the minimum input voltage required for LT1949ES8#PBF to start switching?
The LT1949ES8#PBF can start switching with an input voltage as low as 1.5V, enabling operation from nearly depleted single-cell batteries. This specification is guaranteed across temperature and load conditions, and the device maintains regulation down to this threshold while delivering full 1A peak switch current - a key advantage for ultra-low-voltage portable systems where every millivolt of battery capacity matters. The LT1949ES8#PBF achieves this via optimized bandgap and reference circuitry that remains stable below typical 1.8V startup limits.
Does LT1949ES8#PBF support ceramic output capacitors, and what compensation is recommended?
Yes, the LT1949ES8#PBF is explicitly designed for ceramic output capacitors, enabled by its external VC pin for loop compensation. Linear Technology recommends a 68kΩ resistor in series with a 330pF capacitor from VC to ground when using ceramic outputs - this network provides optimal phase margin and transient response. Using this configuration, the LT1949ES8#PBF achieves stable regulation with 10µF ceramic capacitors (e.g., TAIYO YUDEN LMK325BJ106MN), eliminating bulk electrolytics and reducing solution size by over 40% compared to traditional designs.
How does the low-battery detector in LT1949ES8#PBF function during shutdown mode?
The low-battery detector in the LT1949ES8#PBF remains fully operational during shutdown: the internal 200mV reference and LBI comparator continue drawing only 5–60nA, and LBO retains open-collector sink capability (10µA). This allows continuous battery monitoring without waking the main converter - for example, a microcontroller can read LBO status while the LT1949ES8#PBF is disabled, triggering alerts or graceful shutdown before critical voltage collapse. This behavior is confirmed in the Electrical Characteristics table and Figure 5 of the official datasheet.
What is the maximum achievable output voltage using LT1949ES8#PBF, and what limits it?
The LT1949ES8#PBF supports output voltages up to 28V, limited by its 30V-rated internal switch and absolute maximum SW pin voltage rating of –0.4V to 30V. This is achieved using a single inductor in boost topology - no transformer or charge-pump staging required. Output voltage is set by the FB resistor divider, but practical limits arise from diode reverse voltage rating, inductor saturation current, and PCB layout parasitics. For 28V output, a 40V Schottky diode (e.g., MBRM120LT3) and 15µH inductor are recommended per Linear's application notes.
Is LT1949ES8#PBF pin-compatible with other members of the LT1949 family, such as LT1949IS8?
Yes, the LT1949ES8#PBF is pin-compatible with LT1949IS8 and LT1949EMS8 - all share identical 8-pin SO (S8) or MSOP (MS8) footprints, pin functions, and electrical interface. The suffix denotes temperature grade: 'E' = –40°C to 85°C, 'I' = same range with enhanced screening, 'EMS8' = MSOP package. No PCB redesign is needed when substituting within the same package type; only operating temperature range and long-term reliability specifications differ - confirmed in the Package/Order Information section of the datasheet.
LT1949ES8#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
- 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#PBF FAQ
1.How can I place an order for LT1949ES8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1949ES8#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 LT1949ES8#PBF reliable?
The price and inventory of LT1949ES8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1949ES8#PBF is usually 5 days.
3.What payment methods are accepted for LT1949ES8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1949ES8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1949ES8#PBF?
LT1949ES8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1949ES8#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 LT1949ES8#PBF?
For technical support, including LT1949ES8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1949ES8#PBF requirements.
6.How does Aetrix verify that LT1949ES8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1949ES8#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 LT1949ES8#PBF meets industry standards.
7.What is the process for return or replacement of LT1949ES8#PBF?
All LT1949ES8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1949ES8#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 LT1949ES8#PBF part is unused and in its original packaging.
Return procedure for LT1949ES8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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