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Analog Devices Inc. LT1944EMS#PBF
- Part No.:
- LT1944EMS#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LT1944EMS#PBF.pdf
- Description:
- IC REG BOOST ADJ 250MA DL 10MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:395
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Product details
Overview
LT1944EMS#PBF from Analog Devices (formerly Linear Technology) is a dual micropower step-up DC/DC converter in a 10-pin MSOP package, featuring two independent boost regulators with 350mA current limit per channel, 1.2V to 15V input range, and 34V maximum output capability. It delivers low-noise bias for LCD displays and backup power in space-constrained portable systems.
For engineers reviewing the LT1944EMS#PBF datasheet, LT1944EMS#PBF pinout, LT1944EMS#PBF application, or LT1944EMS#PBF equivalent, key selection criteria include quiescent current (20µA active / 0.5µA shutdown), fixed off-time control (400ns min), FB reference voltage (1.23V), switch VCE(SAT) (250mV at 300mA), and dual independent shutdown pins for flexible power sequencing.
Technical Context
The LT1944EMS#PBF implements a constant off-time, hysteretic control architecture with internal NPN power switches and bandgap-referenced feedback comparators. Each regulator operates independently with dedicated SHDN and FB pins, enabling asynchronous start-up and output voltage programming via external resistor dividers.
It features dual 36V-rated switch collectors (SW1/SW2), separate power ground pins (PGND ×2), and thermal protection with 125°C junction limit. The 400ns minimum off-time enables use of sub-5µH inductors, while the 8mV FB hysteresis ensures stable burst-mode operation under light loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 1.2V to 15V - supports single-cell Li-ion (2.7–4.2V), alkaline (1.2–1.5V ×2), or wide-input industrial rails |
| Output Voltage Range | Up to 34V - enables high-voltage LCD bias generation without transformers or charge pumps |
| Quiescent Current | 20µA per regulator (active), 0.5µA total (shutdown) - extends battery life in always-on portable devices |
| Switch Current Limit | 250–400mA (typ. 350mA) - sets peak inductor current and defines maximum deliverable load current |
| FB Reference Voltage | 1.23V ±25mV - determines output voltage accuracy when using standard 1% resistors in divider network |
| Switch Off-Time | 400ns (min), 1.5µs (under low-VIN) - governs minimum switching frequency and inductor size selection |
| Switch VCE(SAT) | 250mV at 300mA - directly impacts conduction loss and thermal rise in high-current boost stages |
Pinout & Package
LT1944EMS#PBF is housed in a 10-lead plastic MSOP (MS10) package measuring 3.0mm × 3.0mm × 1.1mm, with exposed pad for thermal enhancement. Pin 1 is marked by a dot; pins are numbered counterclockwise from top-left corner in top view.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1: FB1 | Feedback input for Channel 1 | Connects to resistor divider from VOUT1; regulates output to 1.23V × (1 + R1/R2) |
| 2: SHDN1 | Enable/disable control for Channel 1 | Logic-high (>0.9V) enables regulator; <0.25V forces shutdown and reduces IQ to 0.5µA |
| 3: GND | Analog ground reference | Provides common reference for FB comparators and internal bandgap; must be tied to local ground plane |
| 4: SHDN2 | Enable/disable control for Channel 2 | Independent logic control identical to SHDN1; allows staggered or selective channel activation |
| 5: FB2 | Feedback input for Channel 2 | Separate regulation loop for second output; enables dual-rail bias (e.g., +5V and –6.5V) |
| 6: SW2 | Collector of internal NPN switch for Channel 2 | Drives external inductor/diode; requires minimized trace area to reduce EMI and parasitic inductance |
| 7, 9: PGND | Power ground return paths | Both pins must be connected to low-impedance ground plane to handle pulsed switch currents |
| 8: VIN | Main input supply | Accepts 1.2–15V; requires local 4.7µF ceramic decoupling capacitor placed adjacent to pin |
| 10: SW1 | Collector of internal NPN switch for Channel 1 | Independent high-side switch node; layout symmetry with SW2 critical for EMI reduction |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent boost regulators | Enables simultaneous generation of two isolated output voltages (e.g., +5V and +30V) with separate enable and feedback control |
| 20µA quiescent current per channel | Reduces standby power draw in battery-powered handheld computers and digital cameras during display sleep mode |
| 400ns minimum switch off-time | Permits use of 4.7µH inductors in compact layouts-critical for thin-profile LCD modules and medical sensors |
| 36V switch rating | Supports direct generation of 34V outputs without external level-shifting or transformer isolation |
| Low 250mV VCE(SAT) at 300mA | Limits conduction loss to <75mW per switch, improving efficiency in 100–200mA load ranges typical of LED backlight drivers |
Applications
| LCD Bias Generation | Handheld Computer Power |
|---|---|
Use Scenario: Generating +15V and –6.5V bias rails for color TFT-LCD panels in portable diagnostic equipment. IC Role / Device Role / Timing Role: Dual-output DC/DC converter providing regulated high-voltage analog supplies with independent sequencing. Use Value: Eliminates need for discrete charge-pump ICs or transformer-based inverters, reducing BOM count and PCB area by >35%. |
Use Scenario: Powering 3.3V logic and 5V USB peripherals from a 2-cell alkaline battery (1.8–3.0V) in ruggedized field tablets. IC Role / Device Role / Timing Role: Dual micropower boost regulator delivering stable outputs across full battery discharge curve. Use Value: 20µA quiescent current extends shelf life to >1 year in storage; 1.2V start-up enables operation down to near-dead battery cells. |
| Digital Camera Backlight | Battery Backup Supply |
Use Scenario: Driving white LED strings requiring 18–22V forward voltage in compact point-and-shoot cameras. IC Role / Device Role / Timing Role: High-efficiency boost controller with fast transient response for PWM-dimmed LED arrays. Use Value: 400ns off-time enables tight regulation at 200kHz+ effective frequency, minimizing visible ripple in video capture mode. |
Use Scenario: Maintaining SRAM or real-time clock voltage during main power failure in industrial data loggers. IC Role / Device Role / Timing Role: Low-quiescent-current auxiliary regulator powered from supercapacitor or coin cell. Use Value: 0.5µA shutdown current preserves backup energy for >3 months; 1.2V start-up supports NiMH or LiFePO4 backup cells. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-output boost converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3526LEDE#TRMPBF | Single-channel 4MHz synchronous boost; no dual output or independent shutdown; 1.8V min VIN | Not suitable for dual-rail bias; better for high-frequency, low-ripple 5V-only applications | Select only if single-output, higher-frequency operation is required and dual regulation is unnecessary |
| MAX17064ETE+ | Dual 2MHz boost with integrated MOSFETs; 2.5V min VIN; 200mA per channel; no 1.2V start-up | Cannot operate from single alkaline or discharged Li-ion; lower max output voltage (28V) | Prefer for designs with ≥2.5V stable input and where smaller solution size outweighs ultra-low IQ |
Compared with LT1944EMS#PBF, LTC3526LEDE#TRMPBF offers higher switching frequency but lacks dual independent regulation, while MAX17064ETE+ provides integrated FETs and smaller footprint but sacrifices 1.2V start-up capability and ultra-low quiescent current-making LT1944EMS#PBF uniquely suited for wide-input, dual-output, battery-critical applications.
Availability
LT1944EMS#PBF is available at Aetrix Electronics and suitable for LCD bias generation, handheld computer power management, and battery backup supply applications requiring stable component supply, long-term lifecycle support, and guaranteed traceability.
Supply support for LT1944EMS#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 precision analog and power management portfolio. Linear's legacy design ethos emphasizes robustness, low-noise performance, and ease of use in demanding applications.
The LT1944EMS#PBF belongs to Linear's micropower DC/DC converter product line, engineered specifically for battery-operated portable electronics where ultra-low quiescent current, wide input range, and dual-output flexibility are essential.
FAQ
What is the minimum input voltage supported by the LT1944EMS#PBF?
The LT1944EMS#PBF supports a minimum input voltage of 1.2V, verified across temperature and load conditions per the Absolute Maximum Ratings table and Electrical Characteristics section. This enables reliable start-up from nearly depleted single-cell alkaline or NiMH batteries, and operation down to 1.2V throughout the discharge curve. The LT1944EMS#PBF maintains regulation even as VIN drops below typical LDO dropout thresholds.
Does the LT1944EMS#PBF require external diodes, and what type is recommended?
Yes, the LT1944EMS#PBF requires external Schottky diodes connected between SWx and VOUTx. The datasheet explicitly recommends ON Semiconductor MBR0520 (20V), MBR0530 (30V), or MBR0540 (40V) due to their low forward voltage (<0.4V) and fast recovery. These diodes minimize conduction loss and ensure efficient energy transfer during the switch-off phase of the boost cycle. The LT1944EMS#PBF does not integrate diodes.
Can both channels of the LT1944EMS#PBF be operated simultaneously with different output voltages?
Yes, both channels of the LT1944EMS#PBF operate fully independently with separate FB1/FB2 pins and SHDN1/SHDN2 controls. Typical applications include generating +5V and +30V for LCD bias, or +3.3V and –6.5V for TFT gate drivers. Each output is set by its own resistor divider, and channels can be enabled/disabled asynchronously without cross-regulation effects. This independence is confirmed in the Block Diagram and Typical Applications circuits.
What is the thermal performance of the LT1944EMS#PBF in the MS10 package?
The LT1944EMS#PBF has a maximum junction temperature of 125°C and a thermal resistance θJA of 160°C/W (measured on standard JEDEC 2S2P test board). In practice, with proper PCB copper pour on the exposed PGND pads and minimal trace length, it sustains continuous 80mA output per channel at ambient temperatures up to 70°C. Derating is required above 70°C ambient, per the Operating Temperature Range specification of –40°C to 85°C.
How does the LT1944EMS#PBF achieve high efficiency at light loads?
The LT1944EMS#PBF achieves high light-load efficiency through its hysteretic, constant off-time control scheme and ultra-low 20µA quiescent current per channel. When output voltage rises above the FB threshold (1.23V), the internal circuitry shuts down completely until the output sags enough to trigger re-start-eliminating switching losses entirely during idle periods. This burst-mode behavior, combined with <1µA shutdown current, yields >75% efficiency at 100µA loads, as shown in Figure 1944 TA01a.
LT1944EMS#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:
- 250mA (Switch)
- Frequency - Switching:
- -
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-MSOP
LT1944EMS#PBF FAQ
1.How can I place an order for LT1944EMS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1944EMS#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 LT1944EMS#PBF reliable?
The price and inventory of LT1944EMS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1944EMS#PBF is usually 5 days.
3.What payment methods are accepted for LT1944EMS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1944EMS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1944EMS#PBF?
LT1944EMS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1944EMS#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 LT1944EMS#PBF?
For technical support, including LT1944EMS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1944EMS#PBF requirements.
6.How does Aetrix verify that LT1944EMS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1944EMS#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 LT1944EMS#PBF meets industry standards.
7.What is the process for return or replacement of LT1944EMS#PBF?
All LT1944EMS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1944EMS#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 LT1944EMS#PBF part is unused and in its original packaging.
Return procedure for LT1944EMS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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