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Analog Devices Inc. LT1111CN8#PBF
- Part No.:
- LT1111CN8#PBF
- Manufacturer:
- Analog Devices Inc.
- Package:
- 8-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1111CN8#PBF.pdf
- Description:
- IC REG BUCK BOOST ADJ 1.5A 8PDIP
- Quantity:
- Payment:
- Shipping:
Inventory:156
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Product details
Overview
LT1111CN8#PBF from Analog Devices (formerly Linear Technology) is a micropower step-up/step-down DC/DC converter IC with integrated 1.5A NPN power switch, 72kHz gated oscillator, and on-chip low-battery detector comparator. It operates from 2V to 30V input, delivers fixed 5V output at up to 100mA (3V→5V), and supports adjustable output via external resistor divider. Used in battery-powered portable instruments and flash memory VPP generation.
For engineers reviewing the LT1111CN8#PBF datasheet, LT1111CN8#PBF pinout, LT1111CN8#PBF application, or LT1111CN8#PBF equivalent, key selection criteria include its 72kHz oscillator frequency, programmable current limit via ILIM pin, 300µA quiescent current in shutdown, and compatibility with surface-mount inductors in 8-pin PDIP package.
Technical Context
The LT1111CN8#PBF implements a gated-oscillator architecture: the internal 1.25V reference-fed comparator enables the 72kHz oscillator only when feedback voltage falls below threshold, minimizing quiescent current to 300µA. Its dual-mode operation-step-up (boost) with SW2 grounded and SW1 driving inductor/diode, or step-down (buck) with SW1 tied to VIN and SW2 driving inductor-enables flexible topology support without external controller logic.
It integrates an auxiliary open-collector gain block (A0/SET pins) configurable as low-battery detector, linear post-regulator, or error amplifier, and features user-adjustable current limiting via resistor from ILIM to VIN (e.g., 220Ω sets ~400mA limit). The device requires only three external components for basic operation and supports fixed 5V output without external resistors in the -5 variant.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 2V to 30V - supports wide battery input (e.g., single Li-ion down to 2V, 9V/12V systems in buck mode) |
| Output Voltage | Fixed 5V ±2.5% (LT1111CN8-5 variant) - stable regulated output without external feedback resistors |
| Oscillator Frequency | 72kHz typical - optimized for standard surface-mount inductors with minimal EMI concerns |
| Quiescent Current | 300µA (switch OFF) - enables multi-year battery life in low-duty-cycle portable applications |
| Switch Current Limit | Programmable up to 1.5A - prevents inductor saturation and switch overstress across input voltage ranges |
| Operating Temperature | 0°C to 70°C - commercial-grade thermal range suitable for consumer and industrial embedded use |
| Package | 8-lead plastic DIP (N8) - through-hole mounting compatible with legacy PCB assembly and prototyping |
Pinout & Package
LT1111CN8#PBF is housed in an 8-lead plastic DIP (N8) package with 0.3-inch width, lead pitch of 0.1 inch, and JEDEC MS-001 compliant footprint. Pin 1 is marked with notch or dot; top view orientation follows standard DIP numbering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ILIM (Pin 1) | Current limit programming input | Resistor from ILIM to VIN sets switch current limit (e.g., 220Ω → ~400mA); tie directly to VIN for full 1.5A capability |
| VIN (Pin 2) | Main power supply input | Accepts 2V–30V; powers internal circuitry and supplies collector of internal NPN switch in buck mode |
| SW1 (Pin 3) | Power switch collector | In boost: drives inductor/diode node; in buck: connects to VIN - must withstand up to 50V transient |
| SW2 (Pin 4) | Power switch emitter | In boost: connected to GND; in buck: drives inductor/diode - must not fall below –0.5V |
| GND (Pin 5) | Analog and power ground reference | Common return for feedback, comparator, and oscillator; requires low-impedance PCB connection |
| A0 (Pin 6) | Auxiliary gain block output | Open-collector output capable of sinking 300µA - used for low-battery detection or error amplification |
| SET (Pin 7) | Auxiliary gain block inverting input | Connects to 1.25V internal reference; forms op-amp stage with A0 for custom comparator or regulation functions |
| FB/SENSE (Pin 8) | Feedback input / output voltage sense | On LT1111CN8#PBF (adjustable version): connects to resistor divider; on -5/-12 variants: internally tied to output-setting resistors |
Key Features
| Feature | Design Value |
|---|---|
| Three-component operation | Requires only inductor, diode, and output capacitor for functional boost/buck conversion - reduces BOM count and layout area |
| Programmable current limit | Single resistor from ILIM to VIN sets precise switch current threshold - eliminates need for external current-sense ICs |
| Integrated low-battery detector | Comparator with 1.25V reference and 12.5mV hysteresis enables reliable undervoltage warning without extra comparators |
| Gated-oscillator architecture | Switches oscillator ON/OFF based on FB voltage - achieves 300µA quiescent current while maintaining regulation accuracy |
| Dual topology support | Native step-up, step-down, and inverting configurations - no external MOSFET drivers or control logic required |
Applications
| Battery-Powered Portable Instruments | Flash Memory VPP Generation |
|---|---|
|
Use Scenario: Handheld multimeters and data loggers powered by two AA cells (2.0–3.2V) requiring stable 5V rail for microcontroller and ADC. IC Role / Device Role / Timing Role: Step-up DC/DC converter generating regulated 5V output from declining battery voltage. Use Value: Maintains system operation down to 2.0V input with 300µA quiescent current, extending battery life beyond competing converters. |
Use Scenario: Embedded microcontrollers programming EEPROM or NOR flash requiring +12V VPP during write/erase cycles. IC Role / Device Role / Timing Role: Fixed 12V output DC/DC converter activated only during programming sequences. Use Value: Delivers 12V at 50mA from 3V–5V supply using LT1111CN8-12 variant - eliminates need for separate high-voltage charge pump IC. |
| Remote Controls & Peripherals | Uninterruptible Backup Supplies |
|
Use Scenario: IR remote controls using coin-cell batteries (1.8–3.0V) needing clean 5V for RF transmitter IC and MCU. IC Role / Device Role / Timing Role: Micropower boost converter operating in discontinuous conduction mode for burst-mode transmission. Use Value: 72kHz switching frequency avoids audible noise; 300µA shutdown current preserves shelf life of sealed units. |
Use Scenario: Industrial PLC I/O modules with supercapacitor backup that must maintain 5V rail during brief AC mains interruption. IC Role / Device Role / Timing Role: Bidirectional converter supporting both charging (buck) and hold-up (boost) functions. Use Value: Single IC replaces discrete buck charger + boost hold-up circuit - reduces component count and improves reliability. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar DC/DC converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1111CS8-5#PBF | Same electrical specs but in 8-lead SOIC package; θJA = 150°C/W vs 130°C/W for N8 | Preferred for space-constrained PCBs; requires reflow soldering instead of through-hole assembly | Select when board real estate is limited and surface-mount assembly is available. |
| MAX630CPA+ | 5V fixed-output micropower boost converter; 3.2V–16.5V input; 100kHz oscillator; 200µA IQ | Lacks step-down/inverting modes and programmable current limit; no auxiliary gain block | Choose only for simple 3V→5V boost where ultra-low IQ is critical and topology flexibility is unnecessary. |
Compared with LT1111CS8-5#PBF, the LT1111CN8#PBF offers superior thermal performance in through-hole layouts and easier prototyping, while the MAX630CPA+ trades versatility for marginally lower quiescent current in dedicated boost-only designs.
Availability
LT1111CN8#PBF is available at Aetrix Electronics and suitable for battery-powered portable instruments, flash memory VPP generation, and uninterruptible backup supplies requiring stable component supply and long-lifecycle support.
Supply support for LT1111CN8#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 full technical and manufacturing continuity for all Linear DC/DC converter products, including long-term product assurance and qualified second sources.
The LT1111 series was designed for ultra-low-power, multi-topology DC/DC conversion in space- and energy-constrained applications such as handheld test equipment, medical sensors, and memory programming circuits.
FAQ
What is the maximum input voltage rating for the LT1111CN8#PBF?
The LT1111CN8#PBF has an absolute maximum input voltage (VIN) rating of 36V, with recommended operating range up to 30V in step-down mode and 12.6V in step-up mode. Exceeding 30V in buck configuration risks exceeding internal power dissipation limits, especially at elevated ambient temperatures. Always observe the 50V maximum SW1 pin voltage specification when designing for transients.
Can the LT1111CN8#PBF generate a fixed 5V output without external resistors?
No - the LT1111CN8#PBF is the adjustable version and requires an external resistor divider from FB to GND and VOUT to set output voltage. For fixed 5V output, use the LT1111CN8-5#PBF variant, which integrates internal feedback resistors and connects FB directly to output. Using LT1111CN8#PBF as a fixed 5V source without resistors will result in unregulated or undefined output voltage.
How does the ILIM pin function in the LT1111CN8#PBF?
The ILIM pin on the LT1111CN8#PBF allows precise programming of the internal switch current limit by connecting a resistor between ILIM and VIN. A 220Ω resistor sets ~400mA limit; higher resistance lowers the limit. This prevents inductor saturation and switch overstress when input voltage varies - critical in battery-powered systems where VIN drops over time. Leaving ILIM unconnected or floating is not permitted.
What package type is used by the LT1111CN8#PBF?
The LT1111CN8#PBF uses an 8-lead plastic DIP (N8) package with 0.3-inch body width and 0.1-inch lead pitch. It is a through-hole package intended for prototyping, low-volume production, and applications requiring mechanical robustness or serviceability. The "N8" suffix explicitly denotes this PDIP variant, distinct from SOIC (S8) or ceramic DIP (J8) versions.
Does the LT1111CN8#PBF support step-down (buck) operation?
Yes - the LT1111CN8#PBF natively supports step-down operation by reconfiguring external connections: SW1 connects to VIN, SW2 drives the inductor/diode, and GND serves as return. In this mode, it delivers up to 200mA at 5V from a 12V input. Output voltage remains adjustable via FB resistor divider, and the ILIM pin retains current-limit functionality to protect against overcurrent during line transients.
LT1111CN8#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, Step-Down
- Output Configuration:
- Positive or Negative
- Topology:
- Buck, Boost
- Output Type:
- Adjustable
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 2V
- Voltage - Input (Max):
- 30V
- Voltage - Output (Min/Fixed):
- 1.25V
- Voltage - Output (Max):
- 50V (Switch)
- Current - Output:
- 1.5A (Switch)
- Frequency - Switching:
- 72kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 8-PDIP
LT1111CN8#PBF FAQ
1.How can I place an order for LT1111CN8#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1111CN8#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 LT1111CN8#PBF reliable?
The price and inventory of LT1111CN8#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1111CN8#PBF is usually 5 days.
3.What payment methods are accepted for LT1111CN8#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1111CN8#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1111CN8#PBF?
LT1111CN8#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1111CN8#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 LT1111CN8#PBF?
For technical support, including LT1111CN8#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1111CN8#PBF requirements.
6.How does Aetrix verify that LT1111CN8#PBF is sourced from the original manufacturer or authorized distributors?
All LT1111CN8#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 LT1111CN8#PBF meets industry standards.
7.What is the process for return or replacement of LT1111CN8#PBF?
All LT1111CN8#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1111CN8#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 LT1111CN8#PBF part is unused and in its original packaging.
Return procedure for LT1111CN8#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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