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Analog Devices Inc. LTC1911EMS8-1.8#PBF
- Part No.:
- LTC1911EMS8-1.8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-TSSOP, 8-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LTC1911EMS8-1.8#PBF.pdf
- Description:
- IC REG CHG PUMP 1.8V 250MA 8MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:176
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Product details
Overview
LTC1911EMS8-1.8#PBF from Analog Devices (formerly Linear Technology) is a switched-capacitor step-down DC/DC converter delivering a regulated 1.8V ±4% output from 2.7V–5.5V input, supporting up to 250mA load current with no inductor required. It operates at constant 1.5MHz frequency, achieves >25% higher efficiency than LDOs, and integrates short-circuit and overtemperature protection for battery-powered portable electronics.
For engineers reviewing the LTC1911EMS8-1.8#PBF datasheet, LTC1911EMS8-1.8#PBF pinout, LTC1911EMS8-1.8#PBF application, or LTC1911EMS8-1.8#PBF equivalent, key selection considerations include its inductorless architecture, 1.8V fixed output tolerance, Burst Mode™ operation for light-load efficiency, soft-start control via SS/SHDN pin, and MSOP-8 package compatibility with space-constrained handheld designs.
Technical Context
The LTC1911EMS8-1.8#PBF uses fractional switched-capacitor conversion with automatic mode selection (2:1, 3:2, or 1:1) based on input voltage and load conditions to maintain regulation and optimize efficiency across 2.7V–5.5V input range. Its internal control loop regulates charge transfer per cycle rather than duty cycle, enabling low output ripple and stable performance without external inductors.
It implements constant-frequency 1.5MHz operation with integrated oscillator, Burst Mode™ for sub-30mA loads (reducing quiescent current to 180µA typ), and soft-start via external capacitor on SS/SHDN pin to limit inrush current. Shutdown disconnects VOUT from VIN, and internal 2µA pull-up enables open-drain control interface.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | 1.8V ±4% - tightly regulated fixed output suitable for 1.8V logic rails and low-power DSP cores. |
| Max Output Current | 250mA - sufficient for microcontrollers, sensors, and RF front-ends in portable devices. |
| Input Voltage Range | 2.7V to 5.5V - compatible with single-cell Li-ion (2.7–4.2V), 3-cell NiMH (3.6–4.5V), and USB-powered systems. |
| Operating Current | 180µA typical at no load - enables multi-week battery life in always-on monitoring applications. |
| Shutdown Current | 10µA typical - ensures minimal drain during system sleep or standby modes. |
| Oscillator Frequency | 1.5MHz (1.2–1.8MHz range) - enables compact ceramic filtering and reduces EMI compared to lower-frequency charge pumps. |
| Output Ripple | 12mVP-P at 250mA - meets noise-sensitive analog and mixed-signal supply requirements with standard 10µF ceramic output cap. |
Pinout & Package
The LTC1911EMS8-1.8#PBF is housed in an 8-pin MSOP (Mini Small Outline Package) with exposed pad for thermal enhancement, measuring 3.0mm × 3.0mm × 0.85mm and rated for –40°C to +85°C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VIN (Pin 1) | Input supply connection | Accepts 2.7V–5.5V; requires ≥10µF low-ESR ceramic bypass to ground for stable operation. |
| C2+ (Pin 2) | Flying capacitor terminal | Positive node for second flying capacitor (C2); must use non-polarized ceramic (≥1µF). |
| C2– (Pin 3) | Flying capacitor terminal | Negative node for C2; polarity reversal occurs during switching-tantalum/aluminum caps prohibited. |
| GND (Pin 4) | Power and signal reference | Must connect to solid ground plane; critical for noise reduction, thermal dissipation, and regulation stability. |
| C1– (Pin 5) | Flying capacitor terminal | Negative node for first flying capacitor (C1); shares same polarity constraints as C2–. |
| VOUT (Pin 6) | Regulated output | Delivers 1.8V ±4%; disconnected from VIN during shutdown; requires ≥10µF ceramic cap with ESR < 0.1Ω. |
| C1+ (Pin 7) | Flying capacitor terminal | Positive node for C1; forms charge-transfer path in all three operating modes (2:1, 3:2, 1:1). |
| SS/SHDN (Pin 8) | Control interface | Drives shutdown (<0.3V) or enables soft-start via external capacitor; 2µA internal pull-up supports open-drain control. |
Key Features
| Feature | Design Value |
|---|---|
| No-inductor architecture | Eliminates magnetic components, reducing BOM cost, board area, and EMI concerns in ultra-thin portable designs. |
| Constant-frequency 1.5MHz operation | Enables predictable noise spectrum and simplified EMI filtering using small ceramic capacitors instead of bulky LC networks. |
| Burst Mode™ efficiency optimization | Maintains >80% efficiency down to ~1mA load, extending battery runtime without compromising regulation accuracy. |
| Integrated protection | Auto-limits output to ~600mA during short circuit and disables operation above ~160°C junction temperature. |
| Soft-start programmability | External capacitor on SS/SHDN pin controls VOUT ramp rate, limiting inrush current to safe levels for downstream capacitors and FETs. |
Applications
| Handheld Medical Instruments | Smart Card Readers |
|---|---|
Use Scenario: Portable blood glucose meters and pulse oximeters powered by coin-cell or single Li-ion batteries requiring clean, stable 1.8V supply for ADCs and low-power MCUs. IC Role / Device Role / Timing Role: Primary voltage regulator converting variable battery voltage to precise 1.8V rail while minimizing noise coupling into analog front-end circuits. Use Value: Delivers 250mA with <12mVP-P ripple and 180µA quiescent current, enabling >100-hour operation on a 500mAh cell without inductor-induced EMI. | Use Scenario: Contactless smart card readers in point-of-sale terminals where rapid power cycling and low standby drain are mandatory. IC Role / Device Role / Timing Role: System power manager providing controlled 1.8V startup/shutdown sequence and load-disconnect capability during card insertion/removal. Use Value: SS/SHDN pin enables microcontroller-driven soft-start and full VOUT isolation in shutdown, reducing leakage to <10µA and preventing false card detection. |
| Cellular Phones | Low Power DSP Supplies |
Use Scenario: Auxiliary power rail for baseband processors or audio codecs in legacy GSM/EDGE handsets with tight PCB real estate. IC Role / Device Role / Timing Role: Compact, inductorless buck converter supplying 1.8V core voltage with burst-mode efficiency during voice-idle periods. Use Value: Achieves >85% efficiency at 10mA load and fits within 3mm × 3mm footprint-critical for stacked-module phone architectures. | Use Scenario: Dedicated supply for TI C55x or ADI SHARC DSPs operating in low-power active modes with dynamic voltage scaling. IC Role / Device Role / Timing Role: Precision voltage source maintaining 1.8V ±4% under fast load transients (0–250mA) with <33mV droop due to 0.13Ω closed-loop output resistance. Use Value: Load regulation of 0.13mV/mA and 1.5MHz switching ensure stable clocking margins and minimal jitter in high-speed serial interfaces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor step-down converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3250-1.5 | Fixed 1.5V output; 3.1V–5.5V input; 35µA operating current; ThinSOT-6 package | Targeted at lower-voltage logic rails; lacks soft-start pin and Burst Mode™ threshold adjustment | Select when 1.5V output and smaller footprint are prioritized over 1.8V compatibility and programmable startup behavior. |
| LTC3251 | Adjustable 0.9V–1.6V output; 3.1V–5.5V input; 9µA operating current; MS-10 package | Supports dynamic voltage scaling but requires external feedback resistors; no fixed 1.8V option | Choose for systems needing multiple output voltages or tighter light-load efficiency (<10µA), accepting added design complexity. |
Compared with LTC3250-1.5 and LTC3251, the LTC1911EMS8-1.8#PBF offers native 1.8V regulation, integrated soft-start control, and higher output current (250mA vs. 200mA/500mA), making it optimal for fixed-rail, space-constrained applications where simplicity and guaranteed 1.8V compliance are essential.
Availability
LTC1911EMS8-1.8#PBF is available at Aetrix Electronics and suitable for handheld medical instruments, smart card readers, cellular phones, and low-power DSP supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LTC1911EMS8-1.8#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 pioneered high-performance switched-capacitor regulators with proprietary architectures for noise-sensitive applications.
The LTC1911EMS8-1.8#PBF belongs to Linear's switched-capacitor DC/DC converter family, designed specifically for inductorless, low-noise, high-efficiency power conversion in battery-powered portable electronics where board space and EMI are critical constraints.
FAQ
What is the output voltage tolerance of the LTC1911EMS8-1.8#PBF?
The LTC1911EMS8-1.8#PBF delivers a fixed 1.8V output with ±4% tolerance over full temperature range (–40°C to +85°C) and input voltage (2.7V–5.5V). This is confirmed in the Electrical Characteristics table: min 1.73V, typ 1.8V, max 1.87V at 0–250mA load. The tolerance remains stable across line and load variations due to internal bandgap reference and closed-loop charge-pump control.
Does the LTC1911EMS8-1.8#PBF require external inductors?
No, the LTC1911EMS8-1.8#PBF is an inductorless switched-capacitor DC/DC converter. It uses two external 1µF ceramic flying capacitors (C1+, C1–, C2+, C2–) and two 10µF ceramic bypass capacitors (VIN and VOUT) - no inductors are needed. This eliminates magnetic EMI, reduces solution size, and simplifies layout, as explicitly stated in the Features and Typical Application sections of the datasheet.
How does Burst Mode™ operation improve efficiency in the LTC1911EMS8-1.8#PBF?
Burst Mode™ in the LTC1911EMS8-1.8#PBF activates automatically below ~30mA load, shutting down the oscillator and entering a low-current state until VOUT drops sufficiently to trigger another charge burst. This reduces operating current to 180µA (typ) at no load, yielding >25% higher efficiency than LDOs at light loads - verified in Figure G06 showing >80% efficiency at 1mA output current.
What protection features are integrated into the LTC1911EMS8-1.8#PBF?
The LTC1911EMS8-1.8#PBF includes short-circuit current limiting (~600mA) and overtemperature shutdown (~160°C). During short circuit, output current is clamped without latch-up; thermal shutdown disables operation until junction temperature falls to ~150°C, then resumes automatically. These protections are fully integrated and require no external components, as documented in the Applications Information section and Absolute Maximum Ratings table.
Can the LTC1911EMS8-1.8#PBF be used with tantalum or aluminum capacitors?
No - polarized capacitors like tantalum or aluminum are strictly prohibited for flying capacitors (C1, C2) due to voltage reversal during startup, which risks catastrophic failure. For VOUT and VIN bypass, only low-ESR (≤0.1Ω) ceramic capacitors ≥10µF are recommended; tantalum and aluminum caps are discouraged due to high ESR causing instability and degraded transient response, per Layout Considerations and Capacitor Selection Guidelines.
LTC1911EMS8-1.8#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:
- Active
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2.7V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- 1.8V
- Voltage - Output (Max):
- -
- Current - Output:
- 250mA
- Frequency - Switching:
- 1.5MHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-MSOP
LTC1911EMS8-1.8#PBF FAQ
1.How can I place an order for LTC1911EMS8-1.8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LTC1911EMS8-1.8#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 LTC1911EMS8-1.8#PBF reliable?
The price and inventory of LTC1911EMS8-1.8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LTC1911EMS8-1.8#PBF is usually 5 days.
3.What payment methods are accepted for LTC1911EMS8-1.8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LTC1911EMS8-1.8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LTC1911EMS8-1.8#PBF?
LTC1911EMS8-1.8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LTC1911EMS8-1.8#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 LTC1911EMS8-1.8#PBF?
For technical support, including LTC1911EMS8-1.8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LTC1911EMS8-1.8#PBF requirements.
6.How does Aetrix verify that LTC1911EMS8-1.8#PBF is sourced from the original manufacturer or authorized distributors?
All LTC1911EMS8-1.8#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 LTC1911EMS8-1.8#PBF meets industry standards.
7.What is the process for return or replacement of LTC1911EMS8-1.8#PBF?
All LTC1911EMS8-1.8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LTC1911EMS8-1.8#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 LTC1911EMS8-1.8#PBF part is unused and in its original packaging.
Return procedure for LTC1911EMS8-1.8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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