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Analog Devices Inc. LT1949-1EMS8#PBF
- Part No.:
- LT1949-1EMS8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT1949-1EMS8#PBF.pdf
- Description:
- IC REG BST SEPIC ADJ 1A 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,979
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Product details
Overview
LT1949-1EMS8#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency, current-mode step-up DC/DC converter with a 1A, 0.5Ω NPN internal switch and 1.1MHz switching frequency. It generates 10V at 175mA from a 3.3V input, features an external compensation pin (VC), low-battery detector with active shutdown operation, and operates down to 1.5V input. It is designed for LCD bias supplies in portable electronics.
For engineers reviewing the LT1949-1EMS8#PBF datasheet, LT1949-1EMS8#PBF pinout, LT1949-1EMS8#PBF application, or LT1949-1EMS8#PBF equivalent, key selection criteria include its 1.1MHz constant-frequency operation, 30V switch rating enabling up to 28V output, ceramic capacitor compatibility, 8-lead MSOP package, and integrated low-battery detection with 200mV threshold.
Technical Context
The LT1949-1EMS8#PBF uses peak-current-mode control with a 1.1MHz oscillator and internal ramp compensation to prevent subharmonic oscillation above 50% duty cycle. Its error amplifier drives the VC pin via an external RC network to regulate output voltage through the FB pin (1.24V reference).
It integrates a dedicated low-battery detector with 200mV ±5% internal reference, LBI input, and open-collector LBO output that remains functional during shutdown. The 0.5Ω switch exhibits 410mV VCE(SAT) at 800mA, supporting high-efficiency boost conversion with minimal conduction loss.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switching Frequency | 1.1MHz fixed - enables compact LC filter design and ceramic output capacitors |
| Internal Switch | 1A, 0.5Ω NPN transistor - supports 175mA @ 10V from 3.3V input with low conduction loss |
| Feedback Voltage | 1.24V ±20mV - sets output via resistor divider; determines accuracy of regulated VOUT |
| Low-Battery Threshold | 200mV ±10mV on LBI pin - enables precise battery monitoring independent of main regulator state |
| Quiescent Current | 8mA operating / 50µA shutdown - minimizes battery drain in portable standby modes |
| Input Voltage Range | 1.5V to 12V - supports single-cell Li-ion, multi-cell alkaline, and backup supply rails |
| Switch Voltage Rating | 30V - allows output voltages up to 28V using single-inductor topology |
Pinout & Package
LT1949-1EMS8#PBF is housed in an 8-lead plastic MSOP (MS8) package with 0.65mm lead pitch, 3.0mm × 3.0mm body, and exposed pad for thermal enhancement. Pin 4 (GND) must connect directly to local ground plane; wide traces and multiple vias are recommended for SW and GND paths.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VC (Pin 1) | Error amplifier compensation node | Connect external RC network (e.g., 30kΩ + 330pF) to ground for loop stability with ceramic output caps |
| FB (Pin 2) | Feedback input | 1.24V reference point; connects to resistor divider tap to set VOUT = 1.24V × (1 + R1/R2) |
| SHDN (Pin 3) | Shutdown enable | Logic-level input: ≥1.4V enables, ≤0.4V disables; only low-battery detector remains active in shutdown |
| GND (Pin 4) | Power and signal ground | Primary return path; must tie to local ground plane at single point to avoid switching noise coupling |
| SW (Pin 5) | Switch collector node | Connects to inductor and catch diode; high dI/dt node requiring minimized trace area and short routing |
| VIN (Pin 6) | Main power input | Input supply rail (1.5–12V); requires local 3.3µF ceramic bypass capacitor placed within 5mm |
| LBI (Pin 7) | Low-battery detector input | Accepts scaled battery voltage; internal 200mV reference compares against this pin to trigger LBO |
| LBO (Pin 8) | Low-battery open-collector output | Sinks 10µA max; requires external 1MΩ pull-up to monitor battery status during shutdown |
Key Features
| Feature | Design Value |
|---|---|
| Fixed 1.1MHz switching frequency | Enables use of small, low-ESR ceramic output capacitors (e.g., 3.3µF) without electrolytic bulk capacitance |
| External VC compensation | Allows full control over loop dynamics to optimize transient response and stability with varying load/capacitance |
| Active low-battery detector in shutdown | Provides continuous battery monitoring even when main converter is disabled-critical for system wake-on-low-voltage |
| 1A, 0.5Ω internal NPN switch | Delivers high current density in MSOP package while maintaining <410mV saturation voltage at 800mA load |
| 1.5V minimum input voltage | Supports regulation from deeply discharged single-cell Li-ion or two-cell alkaline sources without brownout |
Applications
| LCD Bias Supply | GPS Receiver Power |
|---|---|
Use Scenario: Generating +10V and –8V bias rails for large-screen TFT-LCD panels in handheld medical monitors. IC Role / Device Role / Timing Role: Primary boost converter providing stable 10V output; used in conjunction with charge-pump or inverting stages for dual-rail generation. Use Value: 1.1MHz operation reduces EMI and enables compact 4.7µH inductor + 3.3µF ceramic capacitor solution, minimizing board area in space-constrained devices. | Use Scenario: Powering GPS baseband ICs and RF front-end modules from a 3.3V Li-ion battery in asset trackers. IC Role / Device Role / Timing Role: Step-up regulator delivering clean 5V rail; low quiescent current preserves battery life during periodic location acquisition. Use Value: 50µA shutdown current and active low-battery detection allow reliable end-of-life signaling without additional supervisory ICs. |
| Battery Backup System | Portable Diagnostic Instrument |
Use Scenario: Maintaining real-time clock (RTC) and SRAM retention during main power failure in industrial data loggers. IC Role / Device Role / Timing Role: Standby boost converter activated when primary supply drops below threshold; LBO triggers microcontroller save routine. Use Value: Low-battery detector remains fully operational in shutdown mode, enabling deterministic system-level power management decisions. | Use Scenario: Providing isolated, low-noise analog supply rails for precision ADCs and op-amps in handheld ultrasound probes. IC Role / Device Role / Timing Role: High-efficiency boost stage feeding LDOs; fixed-frequency operation simplifies EMI filtering for sensitive analog sections. Use Value: 1.1MHz constant-frequency PWM avoids beat frequencies with sampling clocks, reducing spurious tones in acquired signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1317BEMS8#PBF | 600kHz switching, lower 0.8A switch current limit, no LBO/LBI pins | Lacks integrated low-battery monitoring; requires external circuitry for battery sensing | Choose when lower EMI and higher efficiency at light loads outweigh need for battery monitoring |
| LT1930ES5#TRPBF | SOT-23-5 package, 1.2MHz, 36V switch rating, no VC or LBI/LBO pins | Smaller footprint but no compensation flexibility or battery detection; limited to simpler boost topologies | Prefer for ultra-compact designs where external feedback compensation and battery alerting are not required |
Compared with LT1317BEMS8#PBF and LT1930ES5#TRPBF, the LT1949-1EMS8#PBF uniquely combines 1.1MHz operation, full compensation control via VC, and integrated low-battery detection-making it optimal for portable systems requiring both compact power conversion and intelligent battery management.
Availability
LT1949-1EMS8#PBF is available at Aetrix Electronics and suitable for LCD bias supplies, GPS receiver power, battery backup systems, portable diagnostic instruments, and portable electronic equipment requiring stable component supply and long-term manufacturability.
Supply support for LT1949-1EMS8#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, Inc. (including former Linear Technology products) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors for precision instrumentation, power management, and signal chain applications.
The LT1949-1EMS8#PBF belongs to Linear's legacy micropower DC/DC converter family, engineered specifically for space-constrained, battery-powered systems needing high-efficiency step-up conversion with intelligent power monitoring capabilities.
FAQ
What is the minimum input voltage supported by the LT1949-1EMS8#PBF?
The LT1949-1EMS8#PBF supports a minimum input voltage of 1.5V, enabling operation from partially discharged single-cell lithium-ion batteries or two-cell alkaline sources. This specification is guaranteed across the full –40°C to 85°C operating temperature range and allows reliable startup and regulation even under deep discharge conditions, making the LT1949-1EMS8#PBF well-suited for portable medical and handheld instrumentation where battery headroom is limited.
How does the low-battery detector function in shutdown mode for the LT1949-1EMS8#PBF?
The LT1949-1EMS8#PBF's low-battery detector remains fully active during shutdown: the internal 200mV reference continues comparing the LBI pin voltage, and LBO outputs an open-collector signal when the threshold is crossed. With only 50µA shutdown current, this feature enables long-term battery monitoring without compromising runtime-critical for applications like data loggers or emergency beacons where the LT1949-1EMS8#PBF must signal end-of-life while main circuitry is powered down.
Can the LT1949-1EMS8#PBF use ceramic output capacitors exclusively?
Yes, the LT1949-1EMS8#PBF is explicitly designed for ceramic output capacitors, enabled by its 1.1MHz fixed-frequency operation and external VC compensation. Typical designs use 3.3µF X5R/X7R ceramics (e.g., Taiyo Yuden LMK325BJ335MD), eliminating electrolytic bulk capacitance. The VC pin allows tuning of phase margin to ensure stability with low-ESR ceramics across temperature and load variations-confirmed in Linear's Figure 1 and layout guidelines for the LT1949-1EMS8#PBF.
What is the purpose of the VC pin on the LT1949-1EMS8#PBF?
VC (Pin 1) is the error amplifier output and compensation node for the LT1949-1EMS8#PBF. It accepts an external series RC network (e.g., 30kΩ + 330pF) tied to ground to set loop gain and phase margin. This flexibility allows designers to optimize transient response and stability for specific output capacitance, ESR, and load profiles-particularly valuable when using ceramic capacitors with near-zero ESR, which can destabilize standard compensation schemes in the LT1949-1EMS8#PBF.
Is the LT1949-1EMS8#PBF pin-compatible with other members of the LT1949 family?
The LT1949-1EMS8#PBF shares the same 8-lead MSOP package and pinout as the LT1949EMS8#PBF (600kHz version), but differs in switching frequency and internal oscillator design. While electrical connections are identical, the LT1949-1EMS8#PBF is not a drop-in replacement due to different compensation requirements and frequency-dependent filter component values. Designers must re-optimize the VC network and output LC components when migrating to the LT1949-1EMS8#PBF from the 600kHz variant.
LT1949-1EMS8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- 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:
- 1.1MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LT1949-1EMS8#PBF FAQ
1.How can I place an order for LT1949-1EMS8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1949-1EMS8#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 LT1949-1EMS8#PBF reliable?
The price and inventory of LT1949-1EMS8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1949-1EMS8#PBF is usually 5 days.
3.What payment methods are accepted for LT1949-1EMS8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1949-1EMS8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1949-1EMS8#PBF?
LT1949-1EMS8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1949-1EMS8#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 LT1949-1EMS8#PBF?
For technical support, including LT1949-1EMS8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1949-1EMS8#PBF requirements.
6.How does Aetrix verify that LT1949-1EMS8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1949-1EMS8#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 LT1949-1EMS8#PBF meets industry standards.
7.What is the process for return or replacement of LT1949-1EMS8#PBF?
All LT1949-1EMS8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1949-1EMS8#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 LT1949-1EMS8#PBF part is unused and in its original packaging.
Return procedure for LT1949-1EMS8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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