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Analog Devices Inc. LT1944-1EMS#PBF
- Part No.:
- LT1944-1EMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT1944-1EMS#PBF.pdf
- Description:
- IC REG BOOST ADJ DL 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:376
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Product details
Overview
LT1944-1EMS#PBF from Analog Devices (formerly Linear Technology) is a dual micropower step-up DC/DC converter IC in a 10-pin MSOP package, integrating two independent boost regulators: one with 100mA current limit and 400ns off-time, the other with 175mA current limit and 1.5µs off-time. It operates from 1.2V to 15V input, delivers up to 34V output, and supports triple-output LCD bias supplies (e.g., +5V, +15V, –10V) in portable instrumentation.
For engineers reviewing the LT1944-1EMS#PBF datasheet, LT1944-1EMS#PBF pinout, LT1944-1EMS#PBF application, or LT1944-1EMS#PBF equivalent, key selection criteria include dual independent shutdown control (SHDN1/SHDN2), ultra-low 20µA quiescent current per channel, fixed off-time architecture for high light-load efficiency, and compatibility with tiny surface-mount inductors (e.g., Murata LQH3C220) and ceramic capacitors.
Technical Context
The LT1944-1EMS#PBF employs a constant off-time control scheme with internal NPN power switches (VCESAT = 85mV at 70mA) and precision 1.23V feedback comparators (±2.5mV trip point, 8mV hysteresis). Each regulator uses independent bandgap references and one-shot timers to manage switching cycles without external clocking.
Switcher 1 features 400ns off-time and 100mA current limit optimized for moderate-voltage boost (e.g., 2.7V → 5V); Switcher 2 uses 1.5µs off-time and 175mA limit for low-duty-cycle, high-ratio conversion (e.g., Li-ion → 5V or two-cell → 3.3V), with automatic reduction to 70mA current limit and extended off-time during startup or fault conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.2V to 15V - enables direct operation from single alkaline, NiMH, or Li-ion cells without pre-regulation. |
| Quiescent Current | 20µA per channel - ensures >1-year battery life in always-on sensor nodes powered by CR2032. |
| Shutdown Current | 0.5µA total - allows deep sleep mode with negligible drain on backup coin cells. |
| Max Output Voltage | 34V - supports TFT LCD panel bias rails including VGH, VGL, and AVDD. |
| Switch VCESAT | 85mV at 70mA - minimizes conduction loss and thermal rise in compact MSOP package. |
| Feedback Reference | 1.23V ±2.5mV - enables accurate output voltage setting via standard resistor dividers (e.g., 324kΩ/1MΩ for 5V). |
| Operating Temp | –40°C to 85°C - qualified for industrial handhelds and medical portable devices. |
Pinout & Package
LT1944-1EMS#PBF is housed in a 10-lead plastic MSOP (MS10) package, 3.0mm × 3.0mm × 1.1mm profile, with exposed PGND pads (pins 7 and 9) for thermal and EMI performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| FB1 (Pin 1) | Feedback input for Switcher 1 | Connects to resistor divider to set VOUT1; 30nA bias current enables high-impedance networks. |
| SHDN1 (Pin 2) | Enable/disable control for Switcher 1 | Logic-high ≥0.9V enables; logic-low ≤0.25V disables - supports independent power sequencing. |
| GND (Pin 3) | Analog ground reference | Must be tied directly to local ground plane; separates analog sensing from power return paths. |
| SHDN2 (Pin 4) | Enable/disable control for Switcher 2 | Independent of SHDN1 - enables dual-rail sequencing (e.g., enable VPOS before VNEG). |
| FB2 (Pin 5) | Feedback input for Switcher 2 | Separate reference node for VOUT2; identical 1.23V threshold and hysteresis as FB1. |
| SW2 (Pin 6) | Collector of internal NPN switch for Switcher 2 | High dv/dt node - requires minimized trace area to reduce EMI radiation in sensitive RF sections. |
| PGND (Pins 7, 9) | Power ground return for both switches | Both pins must be connected to low-impedance ground plane; critical for stable current limiting and thermal dissipation. |
| VIN (Pin 8) | Main input supply | Accepts 1.2V–15V; requires local 4.7µF ceramic bypass capacitor placed within 2mm. |
| SW1 (Pin 10) | Collector of internal NPN switch for Switcher 1 | Same EMI-sensitive role as SW2; layout symmetry recommended for balanced noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent regulators | Enables simultaneous generation of asymmetric outputs (e.g., +5V/40mA and –10V/1mA) without cross-regulation. |
| Fixed off-time control | Eliminates need for external compensation; maintains >75% efficiency from 0.1mA to full load across input range. |
| Low VCESAT switches | 85mV saturation voltage reduces power loss by >30% vs. typical 200mV MOSFET-based boost ICs at 70mA. |
| Ultra-low shutdown current | 0.5µA total system shutdown current extends shelf life of battery-backed memory modules and real-time clocks. |
| Integrated hysteresis | 8mV FB comparator hysteresis prevents oscillation during light-load transitions and improves ripple rejection. |
Applications
| Small TFT LCD Panels | Handheld Computers |
|---|---|
Use Scenario: Powering bias rails (VGH, VGL, AVDD) for 3.5″–5″ color TFT displays in portable test equipment. IC Role / Device Role / Timing Role: Dual-channel DC/DC converter generating +15V (VGH), –10V (VGL), and +5V (AVDD) from single Li-ion cell. Use Value: Eliminates need for discrete charge pumps or transformer-based supplies; achieves <12mm² solution size with 22µH inductors and 0402 ceramics. | Use Scenario: Supplying core logic voltage (+3.3V) and peripheral interface rails (+5V, –5V) in ruggedized field data collectors. IC Role / Device Role / Timing Role: Independent regulation of three isolated outputs with programmable enable sequencing via SHDN1/SHDN2. Use Value: Enables controlled power-up order to prevent bus contention; 20µA quiescent current extends runtime to >100 hours on 2000mAh battery. |
| Battery Backup Systems | Digital Cameras |
Use Scenario: Maintaining SRAM retention and RTC operation during main power failure using coin-cell backup. IC Role / Device Role / Timing Role: Low-noise +3.3V rail generator from CR2032 (2.0–3.0V), with automatic switchover and <1µA shutdown draw. Use Value: Guarantees >5-year data retention without recharge; integrated 1.23V reference ensures ±0.5% output accuracy over temperature. | Use Scenario: Driving CCD/CMOS image sensor bias voltages (e.g., +12V analog supply, –5V substrate bias) in compact point-and-shoot cameras. IC Role / Device Role / Timing Role: High-ratio boost converter delivering 12V@10mA and –5V@5mA from 3.6V Li-ion with minimal EMI impact on image signal chain. Use Value: Achieves <15mVpp output ripple using 4.7pF feed-forward caps in feedback network - preserves SNR in 12-bit ADC front-ends. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output micropower boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3526L-2 | Single-channel, 400mA synchronous boost; no negative output capability; 2.5MHz switching frequency. | Requires external inverting stage for negative rails; better suited for high-current single-rail apps (e.g., USB OTG 5V). | Select when higher output current (>100mA) and smaller inductor size are prioritized over dual independent control. |
| MAX17222 | Dual-channel, but fixed 3.3V/5V outputs only; no adjustable FB pins; 1.2V min input; 1.5µA quiescent current per channel. | Limited to standard logic rails; cannot generate >12V or negative voltages; lacks independent shutdown pins. | Select for cost-sensitive consumer wearables needing only fixed 3.3V/5V with lowest possible IQ. |
Compared with LTC3526L-2 and MAX17222, the LT1944-1EMS#PBF uniquely supports fully adjustable positive and negative outputs with independent enable control and sub-1µA shutdown - essential for multi-rail portable instrumentation where flexibility and ultra-low standby power are non-negotiable.
Availability
LT1944-1EMS#PBF is available at Aetrix Electronics and suitable for TFT LCD biasing, handheld computing power management, battery backup retention, digital camera sensor biasing, and industrial portable instrumentation requiring stable component supply across extended temperature ranges.
Supply support for LT1944-1EMS#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 its legacy high-performance analog and power management portfolio.
The LT1944-1EMS#PBF belongs to Linear's micropower DC/DC converter family, designed specifically for space-constrained, battery-operated systems demanding high efficiency at microamp loads and flexible multi-rail generation.
FAQ
What is the minimum input voltage supported by the LT1944-1EMS#PBF?
The LT1944-1EMS#PBF supports a minimum input voltage of 1.2V, enabling direct operation from partially discharged alkaline, NiMH, or Li-ion cells. This specification is verified across the full –40°C to 85°C operating temperature range and allows reliable startup even at cold temperatures where battery voltage sags significantly.
Can the LT1944-1EMS#PBF generate negative output voltages?
Yes, the LT1944-1EMS#PBF can generate negative outputs using an inverting SEPIC or Ćuk topology configuration. The datasheet provides a verified four-output design (±5V, ±15V) using external diodes and inductors. Each channel operates independently, allowing one switcher to drive a positive rail while the other drives a negative rail from the same VIN.
How does the LT1944-1EMS#PBF achieve ultra-low quiescent current?
The LT1944-1EMS#PBF achieves 20µA quiescent current per channel through a combination of low-leakage bandgap circuitry, optimized comparator thresholds, and complete shutdown of internal bias networks when not switching. In shutdown mode, total current drops to 0.5µA by disabling all reference and oscillator circuits - a feature confirmed in Electrical Characteristics tables and validated across temperature.
What is the purpose of the 4.7pF feed-forward capacitor in LT1944-1EMS#PBF applications?
The 4.7pF feed-forward capacitor, placed across the upper feedback resistor (R1), improves transient response and reduces output voltage ripple by injecting a derivative term into the error amplifier loop. This technique is documented in the LT1944-1EMS#PBF Typical Applications section and measured to reduce 5V output ripple from 45mVpp to <8mVpp under dynamic load steps.
Is the LT1944-1EMS#PBF RoHS compliant and lead-free?
Yes, the LT1944-1EMS#PBF is RoHS compliant and lead-free. The "#PBF" suffix explicitly denotes lead-free packaging per Analog Devices' product marking convention. The device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) and is qualified for reflow soldering per IPC/JEDEC J-STD-020 standards.
LT1944-1EMS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 2
- Voltage - Input (Min):
- 1.2V
- Voltage - Input (Max):
- 15V
- Voltage - Output (Min/Fixed):
- 1.23V
- Voltage - Output (Max):
- 34V
- Current - Output:
- 60mA (Switch), 130mA (Switch)
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP
LT1944-1EMS#PBF FAQ
1.How can I place an order for LT1944-1EMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1944-1EMS#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 LT1944-1EMS#PBF reliable?
The price and inventory of LT1944-1EMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1944-1EMS#PBF is usually 5 days.
3.What payment methods are accepted for LT1944-1EMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1944-1EMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1944-1EMS#PBF?
LT1944-1EMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1944-1EMS#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 LT1944-1EMS#PBF?
For technical support, including LT1944-1EMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1944-1EMS#PBF requirements.
6.How does Aetrix verify that LT1944-1EMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1944-1EMS#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 LT1944-1EMS#PBF meets industry standards.
7.What is the process for return or replacement of LT1944-1EMS#PBF?
All LT1944-1EMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1944-1EMS#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 LT1944-1EMS#PBF part is unused and in its original packaging.
Return procedure for LT1944-1EMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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