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Analog Devices Inc. LT1109CS8#TRPBF
- Part No.:
- LT1109CS8#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1109CS8#TRPBF.pdf
- Description:
- IC REG BOOST ADJ 1.2A 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:3,801
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Product details
Overview
LT1109CS8#TRPBF from Analog Devices (formerly Linear Technology) is a micropower step-up DC/DC converter in 8-lead SOIC package, delivering fixed 5V or 12V output with 320µA quiescent current, 1.6V minimum start-up voltage, and 120kHz oscillator frequency. It serves as a flash memory VPP generator and low-cost 3V-to-5V/5V-to-12V converter in battery-powered peripherals and PC plug-in cards.
For engineers reviewing the LT1109CS8#TRPBF datasheet, LT1109CS8#TRPBF pinout, LT1109CS8#TRPBF application, or LT1109CS8#TRPBF equivalent, key selection criteria include logic-controlled shutdown capability, fixed-output configuration, surface-mount inductor compatibility (e.g., 33µH), output ripple ≤50mV (5V version), and operation across 0°C to 70°C ambient temperature.
Technical Context
The LT1109CS8#TRPBF integrates a gated-oscillator architecture with internal 1.25V reference and comparator hysteresis (8–12.5mV), enabling stable regulation without external frequency compensation. Its N-channel power switch features 0.4V typical saturation voltage at 500mA and supports up to 1.2A peak switch current.
Input voltage range is 3V to 5V for the -5 variant and 3V to 12V for the -12 variant; output voltage tolerance is ±5% (4.75–5.25V or 11.52–12.55V). The SHUTDOWN pin accepts TTL-compatible logic levels (VIH ≥2.0V, VIL ≤0.8V) and reduces operating current to 320µA when asserted low.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5V or 12V; tightly regulated ±5% over line/load/temperature |
| Oscillator Frequency | 120kHz typical; enables use of small surface-mount inductors (e.g., 33µH) |
| Quiescent Current | 320µA at no load; minimizes battery drain in standby mode |
| Minimum Start-Up Voltage | 1.6V at VOUT pin; allows operation from single-cell or low-voltage sources |
| Switch Saturation Voltage | 0.4V typical at 500mA; reduces conduction loss and improves efficiency |
| Duty Cycle | 45–60% at full load; optimized for step-up conversion efficiency |
| SHUTDOWN Input Logic | TTL-compatible; VIH ≥2.0V, VIL ≤0.8V; disables oscillator when low |
Pinout & Package
LT1109CS8#TRPBF is housed in an 8-lead plastic SOIC (S8) package with 1.27mm lead pitch, JEDEC MS-012AC compliant, θJA = 150°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (VIN) | Input Power Supply | Accepts 3V–5V input; powers internal circuitry independently of VOUT |
| 2 (NC) | No Connect | Not internally bonded; must be left unconnected |
| 3 (SW) | Switch Node | Drives external inductor; connects to cathode of catch diode |
| 4 (GND) | Ground Reference | Power and signal ground return for all internal blocks |
| 5 (SENSE) | Feedback Sense Input | Monitors output via resistor divider; sets regulation threshold at 1.25V |
| 6 (SHUTDOWN) | Enable Control Input | Active-low logic input; disables oscillator and halts switching when low |
| 7 (NC) | No Connect | Not internally bonded; must be left unconnected |
| 8 (NC) | No Connect | Not internally bonded; must be left unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Logic-Controlled Shutdown | Reduces system-level standby power by disabling switching while maintaining 320µA supply current |
| Gated-Oscillator Architecture | Eliminates need for external frequency compensation components, simplifying BOM and layout |
| Low-Component Count Design | Requires only three external parts: inductor, diode, and output capacitor - ideal for cost-sensitive designs |
| Bootstrapped Feedback Sensing | Uses internal 1.25V reference and comparator hysteresis to stabilize regulation without trimming |
| Surface-Mount Optimized | Validated with off-the-shelf 33µH SMT inductors (e.g., Sumida CD54-330LC), enabling compact PCB footprint |
Applications
| Flash Memory Programming | 3V-to-5V Portable Conversion |
|---|---|
Use Scenario: Generating +12V VPP programming voltage for NOR/NAND flash memory in embedded data loggers and firmware-upgradable modules. IC Role / Device Role / Timing Role: Step-up DC/DC converter providing regulated high-voltage rail during write/erase cycles. Use Value: Enables reliable flash programming from single 3.3V or dual-cell battery inputs without discrete charge pumps or transformers. | Use Scenario: Powering 5V logic interfaces (e.g., UART, SPI peripherals) from 3V coin-cell or Li-ion sources in handheld test equipment. IC Role / Device Role / Timing Role: Fixed-output boost regulator supplying clean, low-noise 5V rail with minimal quiescent draw. Use Value: Delivers 100mA at 5V from 3V input with ≤50mV output ripple, extending battery life beyond 1000 hours in sleep mode. |
| Disk Drive Interface Power | PC Plug-In Card Auxiliary Rail |
Use Scenario: Providing isolated 5V or 12V auxiliary power for IDE/CF card interface circuitry in portable storage devices. IC Role / Device Role / Timing Role: Compact, thermally efficient boost converter supporting intermittent high-current bursts during disk spin-up. Use Value: Handles 60mA continuous 12V output from 5V input with 0.4V switch saturation, minimizing thermal rise in confined enclosures. | Use Scenario: Generating local 5V or 12V rails on PCIe add-in cards where main board supplies are unavailable or noisy. IC Role / Device Role / Timing Role: Standalone DC/DC solution with shutdown control synchronized to host power management signals. Use Value: Allows hot-plug compatible power sequencing via SHUTDOWN pin, eliminating need for external enable logic or LDO post-regulation. |
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 |
|---|---|---|---|
| LT1109CN8#PBF | DIP-8 package instead of SOIC-8; identical electrical specs and pinout; higher θJA (130°C/W) | Suitable for through-hole prototyping or legacy board rework; less space-efficient than SOIC | Select when manual soldering or socket-based testing is required; avoid for high-density SMT production. |
| LT1301CS8#TRPBF | 20µA shutdown current (vs. 320µA), 200mA 12V output capability, same SOIC-8 footprint | Better suited for ultra-low-power systems requiring deeper sleep states or higher load currents | Choose when >60mA 12V output or sub-100µA shutdown current is mandatory; note higher cost and different feedback network. |
Compared with LT1109CS8#TRPBF, LT1109CN8#PBF offers identical functionality in through-hole format but sacrifices thermal performance and board area efficiency, while LT1301CS8#TRPBF delivers superior shutdown efficiency and output current at the expense of increased complexity and cost.
Availability
LT1109CS8#TRPBF is available at Aetrix Electronics and suitable for flash memory VPP generation, 3V-to-5V portable conversion, and PC plug-in card auxiliary rail applications requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT1109CS8#TRPBF 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 ICs emphasize simplicity, reliability, and minimal external component count.
The LT1109 product line was designed for cost-sensitive, battery-powered applications requiring simple, robust step-up conversion - especially flash programming, peripheral interface rails, and low-power embedded subsystems.
FAQ
What is the maximum output current capability of the LT1109CS8#TRPBF?
The LT1109CS8#TRPBF delivers up to 100mA at 5V when supplied from a 3V input, and up to 60mA at 12V from a 5V input. These values reflect guaranteed performance under typical conditions (TA = 25°C, proper external component selection). Peak switch current is rated at 1.2A, but sustained output depends on thermal limits, inductor DCR, and diode forward drop. Derating is required above 70°C ambient.
Does the LT1109CS8#TRPBF require external frequency compensation components?
No, the LT1109CS8#TRPBF does not require external frequency compensation components. Its gated-oscillator design incorporates built-in hysteresis (8–12.5mV) and a fixed 120kHz oscillator, eliminating the need for compensation networks. This simplifies design, reduces BOM count, and improves reliability compared to adjustable-compensation boost controllers.
Can the LT1109CS8#TRPBF operate from a 2V input source?
No, the LT1109CS8#TRPBF cannot reliably start or regulate from a 2V input. Its minimum start-up voltage is 1.6V at the VOUT pin, but the input voltage (VIN) must be ≥3V for the -5 and -12 variants per datasheet specifications. Operation below 3V violates absolute maximum ratings and results in undefined behavior or failure to initiate switching.
What is the purpose of the NC pins on the LT1109CS8#TRPBF SOIC package?
The LT1109CS8#TRPBF has NC (No Connect) pins at positions 2, 7, and 8. These pins are not internally bonded and serve no electrical function. They must remain unconnected in PCB layout and schematic design. Leaving them floating or tying them to GND/VIN has no effect on operation but may risk mechanical stress or unintended coupling if misrouted.
How does the SHUTDOWN pin function on the LT1109CS8#TRPBF?
The SHUTDOWN pin on the LT1109CS8#TRPBF is an active-low TTL-compatible control input. When pulled below 0.8V (VIL), it disables the internal oscillator and halts switching, reducing total supply current to 320µA. When held ≥2.0V (VIH) or left open, the device operates normally. No pull-up resistor is required, as internal bias ensures default enable state.
LT1109CS8#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Step-Up
- Output Configuration:
- Positive
- Topology:
- Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 3V
- Voltage - Input (Max):
- 20V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 50V (Switch)
- Current - Output:
- 1.2A (Switch)
- Frequency - Switching:
- 120kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
LT1109CS8#TRPBF FAQ
1.How can I place an order for LT1109CS8#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1109CS8#TRPBF 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 LT1109CS8#TRPBF reliable?
The price and inventory of LT1109CS8#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1109CS8#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1109CS8#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1109CS8#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1109CS8#TRPBF?
LT1109CS8#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1109CS8#TRPBF 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 LT1109CS8#TRPBF?
For technical support, including LT1109CS8#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1109CS8#TRPBF requirements.
6.How does Aetrix verify that LT1109CS8#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1109CS8#TRPBF 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 LT1109CS8#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1109CS8#TRPBF?
All LT1109CS8#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1109CS8#TRPBF, 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 LT1109CS8#TRPBF part is unused and in its original packaging.
Return procedure for LT1109CS8#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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