DocumentationDatasheet
Application Note
- AN20 - Application Considerations for an Instrumentation Lowpass Filter
- AN60 - PCMCIA Card and Card Socket Power Management:
- AN66 - Linear Technology Magazine Circuit Collection, Volume II
Design Note
Reliability Data
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ltspice
Features
- Operates at Supply Voltages from 2V to 30V
- Works with Surface Mount Inductors
- 72kHz Oscillator
- Only Three External Components Required
- Step-Up or Step-Down Mode
- Low-Battery Detector Comparator On-Chip
- User Adjustable Current Limit
- Internal 1A Power Switch
- Fixed or Adjustable Output Voltage Versions
- Space Saving 8-Pin MiniDIP or SO-8 Package
Typical Application
Description
The LT1111 is a versatile micropower DC/DC converter. The device requires only three external components to deliver a fixed output of 5V or 12V. Supply voltage ranges from 2V to 12V in step-up mode and to 30V in step-down mode. The LT1111 functions equally well in step-up, step-down, or inverting applications.
The LT1111 oscillator is set at 72kHz, optimizing the device to work with off-the-shelf surface mount inductors. The device can deliver 5V at 100mA from a 3V input in step-up mode or 5V at 200mA from a 12V input in step-down mode.
Switch current limit can be programmed with a single resistor. An auxiliary open-collector gain block can be configured as a low-battery detector, linear post regulator, undervoltage lock-out circuit, or error amplifier.
For input sources of less than 2V use the LT1110.
N-8,SO-8
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT1111CN8#PBF | PDIP | 8 | C | $2.83 | $2.30 |
| LT1111CN8-12#PBF | PDIP | 8 | C | $2.83 | $2.30 |
| LT1111CN8-5#PBF | PDIP | 8 | C | $2.83 | $2.30 |
| LT1111CS8#PBF | SO | 8 | C | $3.25 | $2.65 |
| LT1111CS8#TRPBF | SO | 8 | C | $2.71 | |
| LT1111CS8-12#PBF | SO | 8 | C | $3.25 | $2.65 |
| LT1111CS8-12#TRPBF | SO | 8 | C | $2.71 | |
| LT1111CS8-5#PBF | SO | 8 | C | $3.25 | $2.65 |
| LT1111CS8-5#TRPBF | SO | 8 | C | $2.71 | |
| LT1111IS8#PBF | SO | 8 | I | $4.25 | $3.45 |
| LT1111IS8#TRPBF | SO | 8 | I | $3.51 | |
| LT1111CN8 | PDIP | 8 | C | $5.66 | $4.60 |
| LT1111CN8-12 | PDIP | 8 | C | $5.66 | $4.60 |
| LT1111CN8-5 | PDIP | 8 | C | $5.66 | $4.60 |
| LT1111CS8 | SO | 8 | C | $6.50 | $5.30 |
| LT1111CS8#TR | SO | 8 | C | $5.42 | |
| LT1111CS8-12 | SO | 8 | C | $6.50 | $5.30 |
| LT1111CS8-12#TR | SO | 8 | C | $5.42 | |
| LT1111CS8-5 | SO | 8 | C | $6.50 | $5.30 |
| LT1111CS8-5#TR | SO | 8 | C | $5.42 | |
| LT1111IS8 | SO | 8 | I | $8.50 | $6.90 |
| LT1111IS8#TR | SO | 8 | I | $7.02 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.