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Analog Devices Inc. LT1109CN8#PBF
- Part No.:
- LT1109CN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1109CN8#PBF.pdf
- Description:
- IC REG BOOST ADJ 1.2A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,438
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Product details
Overview
LT1109CN8#PBF from Analog Devices (formerly Linear Technology) is a micropower step-up DC/DC converter in an 8-pin plastic DIP package, delivering fixed 5V or 12V output with 120kHz oscillator frequency, 320µA quiescent current, and logic-controlled shutdown. It serves as a flash memory VPP generator and 3V-to-5V/5V-to-12V converter in battery-powered peripherals and PC plug-in cards.
For engineers reviewing the LT1109CN8#PBF datasheet, LT1109CN8#PBF pinout, LT1109CN8#PBF application, or LT1109CN8#PBF equivalent, key selection criteria include minimum 1.6V start-up voltage, 3-external-component design simplicity, adjustable/fixed output variants, and SHUTDOWN pin compatibility with TTL logic levels.
Technical Context
The LT1109CN8#PBF implements a gated-oscillator architecture with internal 1.25V reference and comparator-based feedback control. Its 120kHz fixed-frequency operation enables use of small surface-mount inductors (e.g., 33µH), while the separate SENSE pin allows input-side power sourcing to reduce quiescent power dissipation.
It features a built-in 1.2A switch with 0.7V typical saturation voltage at 500mA, hysteresis-compensated regulation (8–12.5mV), and logic-level SHUTDOWN pin (VIH = 2.0V, VIL = 0.8V) that disables the oscillator without increasing quiescent current beyond 320µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Voltage | Fixed 5V (±2.5%) or 12V (±4.6%) - stable for flash VPP programming and peripheral rail generation |
| Oscillator Frequency | 120kHz (±16.7%) - enables compact 33µH inductor and low-ESR capacitor selection |
| Quiescent Current | 320µA at shutdown - minimizes battery drain in always-on standby modes |
| Start-Up Voltage | 1.6V minimum - supports single-cell Li-ion or dual-cell alkaline operation |
| Switch Saturation Voltage | 0.7V at 500mA - limits conduction loss and thermal rise in high-current pulses |
| Duty Cycle | 50% typical at full load - balances efficiency and ripple across input range |
| SHUTDOWN Input Threshold | VIL ≤ 0.8V, VIH ≥ 2.0V - compatible with standard CMOS/TTL logic interfaces |
Pinout & Package
LT1109CN8#PBF uses an 8-lead plastic DIP (N8) package with 0.300-inch width, 0.100-inch lead pitch, and through-hole mounting. Thermal resistance θJA is 130°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 | VIN | Input supply connection - powers internal circuitry directly from source (not VOUT) |
| 2 | NC | No connect - unused terminal; must remain unconnected |
| 3 | SW | Switch node - connects to inductor and catch diode anode; carries pulsed 1.2A peak current |
| 4 | GND | Power and signal ground - common return for VIN, SW, SENSE, and SHUTDOWN |
| 5 | SENSE | Feedback input - monitors regulated output via resistor divider; sets output voltage in fixed versions |
| 6 | SHUTDOWN | Active-low enable - pulls oscillator low when ≤0.8V; draws <20µA when asserted |
| 7 | NC | No connect - unused terminal; must remain unconnected |
| 8 | NC | No connect - unused terminal; must remain unconnected |
Key Features
| Feature | Design Value |
|---|---|
| Logic-Controlled Shutdown | Reduces system-level power consumption without requiring external MOSFETs or level shifters |
| Separate VIN and SENSE Pins | Enables lower-quiescent-power operation by powering IC from input rail instead of boosted output |
| Gated-Oscillator Architecture | Eliminates need for external frequency compensation components and simplifies layout |
| 1.2A Internal Power Switch | Supports up to 100mA at 5V or 60mA at 12V output without external transistor |
| 320µA Quiescent Current | Extends battery life in portable equipment where standby current dominates total energy budget |
Applications
| Flash Memory Programming | Disk Drive Power Supply |
|---|---|
Use Scenario: Generating +12V VPP programming voltage for EPROM/EEPROM devices in embedded test fixtures. IC Role / Device Role / Timing Role: Step-up DC/DC converter providing regulated high-voltage rail during write cycles. Use Value: Enables reliable flash programming from 3V–5V battery sources using only three external components. | Use Scenario: Supplying auxiliary 12V rail for voice coil motor drivers in 2.5-inch HDD actuator circuits. IC Role / Device Role / Timing Role: Compact boost converter delivering stable 12V at 60mA with fast transient response. Use Value: Replaces discrete charge-pump solutions with higher efficiency and lower EMI in space-constrained drives. |
| PC Plug-In Card Power | Battery-Powered Peripherals |
Use Scenario: Providing isolated 5V or 12V rails on ISA/PCI add-in cards powered from motherboard 5V bus. IC Role / Device Role / Timing Role: Fixed-output boost regulator with SHUTDOWN control for dynamic power gating. Use Value: Reduces card-level heat generation and improves compatibility with legacy backplane power budgets. | Use Scenario: Powering USB hubs or Bluetooth modules from two AA cells in portable diagnostic tools. IC Role / Device Role / Timing Role: Micropower DC/DC converter maintaining regulated output down to 1.6V input. Use Value: Maximizes runtime by sustaining operation until battery reaches end-of-discharge voltage. |
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 |
|---|---|---|---|
| LT1301CS8#PBF | 20µA shutdown current vs. 320µA; 200mA 12V output capability; higher cost | Preferred for ultra-low-power sleep modes and higher-current 12V loads | Select LT1301CS8#PBF when >100mA 12V output or sub-50µA shutdown is required |
| MAX680ESA+ | Charge-pump topology (no inductor); fixed ±10V dual output; 100kHz switching | Suitable for low-noise analog biasing but not high-current VPP generation | Choose MAX680ESA+ only for low-EMI, inductor-free dual-rail applications under 30mA |
Compared with LT1109CN8#PBF, LT1301CS8#PBF offers deeper shutdown and higher output current but requires more board area and cost; MAX680ESA+ eliminates magnetics but lacks programmable output and cannot support flash VPP-level currents.
Availability
LT1109CN8#PBF is available at Aetrix Electronics and suitable for flash memory programming, disk drive auxiliary power, and battery-powered peripheral designs requiring stable component supply with long-term industrial availability.
Supply support for LT1109CN8#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. (acquired Linear Technology in 2017) is a global semiconductor leader specializing in high-performance analog, mixed-signal, and power management ICs.
The LT1109 product line was designed specifically for cost-sensitive, low-power DC/DC conversion in portable and peripheral systems where minimal external components and guaranteed start-up below 2V are critical.
FAQ
What is the minimum input voltage required for LT1109CN8#PBF to start regulating?
The LT1109CN8#PBF has a guaranteed minimum start-up voltage of 1.6V at the VIN pin. This allows reliable operation from partially discharged batteries, including single-cell lithium-ion (2.7V–4.2V) and dual-cell alkaline (2.0V–3.2V) sources. Below 1.6V, the internal oscillator will not initiate, and no regulated output is generated. The LT1109CN8#PBF maintains regulation across its full specified input range of 3V to 12V once started.
Can LT1109CN8#PBF be used to generate 12V from a 3V input?
Yes, the LT1109CN8#PBF can generate 12V from a 3V input when configured as the LT1109CN8-12 variant. However, output current is limited to approximately 30mA at 3V input due to duty cycle and switch limitations. For higher current (e.g., 60mA), a 5V input is recommended per the datasheet specifications. The LT1109CN8#PBF's 1.2A internal switch and 120kHz oscillator support this conversion, but inductor and diode selection must accommodate the higher voltage ratio and peak currents.
Does LT1109CN8#PBF require external frequency compensation components?
No, the LT1109CN8#PBF does not require external frequency compensation components. Its gated-oscillator design incorporates built-in hysteresis (8–12.5mV) in the error amplifier, which stabilizes regulation without loop compensation networks. This simplifies design, reduces bill-of-materials count, and improves reliability-consistent with the "only three external components" claim in the official documentation for the LT1109CN8#PBF.
What is the function of the SENSE pin on LT1109CN8#PBF?
The SENSE pin on LT1109CN8#PBF is the feedback input that monitors the regulated output voltage via an external resistor divider. In fixed-output versions (e.g., LT1109CN8-5 or LT1109CN8-12), the divider is internal, and SENSE connects directly to the output. Its role is to compare the scaled output against the internal 1.25V reference and control the oscillator to maintain regulation. Unlike adjustable versions, the LT1109CN8#PBF uses SENSE as the sole feedback path with no FB pin.
Is LT1109CN8#PBF RoHS compliant and lead-free?
Yes, LT1109CN8#PBF is RoHS compliant and lead-free. The "#PBF" suffix explicitly denotes lead-free packaging per Analog Devices' part numbering convention. It meets EU Directive 2011/65/EU and is manufactured with matte tin lead finish. The device operates over 0°C to 70°C and supports reflow soldering profiles compliant with J-STD-020, with maximum lead temperature rated at 300°C for 10 seconds.
LT1109CN8#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 8-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1109CN8#PBF FAQ
1.How can I place an order for LT1109CN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1109CN8#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 LT1109CN8#PBF reliable?
The price and inventory of LT1109CN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1109CN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1109CN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1109CN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1109CN8#PBF?
LT1109CN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1109CN8#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 LT1109CN8#PBF?
For technical support, including LT1109CN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1109CN8#PBF requirements.
6.How does Aetrix verify that LT1109CN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1109CN8#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 LT1109CN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1109CN8#PBF?
All LT1109CN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1109CN8#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 LT1109CN8#PBF part is unused and in its original packaging.
Return procedure for LT1109CN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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