DocumentationDatasheet
Application Note
Design Note
Reliability Data
cad_symbol
ltspice
Features
- Dropout Voltage: 0.5V
- Output Current: 300mA
- Quiescent Current: 12µA
- No Protection Diodes Needed
- Adjustable Output from 3.8V to 20V
- Fixed Output Voltages: 3V, 3.3V, 5V
- Controlled Quiescent Current in Dropout
- Shutdown IQ = 6µA
- Reverse Battery Protection
- No Reverse Current
- Thermal Limiting
Typical Application
Description
The LT1521/LT1521-3/LT1521-3.3/LT1521-5 are low dropout regulators with micropower quiescent current and shutdown. These devices are capable of supplying 300mA of output current with a dropout voltage of 0.5V.Designed for use in battery-powered systems, the low quiescent current, 12uA operating and 6uA in shutdown, makes them an ideal choice. The quiescent current is well controlled; it does not rise in dropout as it does with many other low dropout PNP regulators.
Other features of the LT1521/LT1521-3/LT1521-3.3/LT1521-5 include the ability to operate with very small output capacitors. They are stable with only 1.5uF on the output while most older devices require between 10uF and 100uF for stability. Small ceramic capacitors can be used,enhancing manufacturability. Also, the input may be connected to voltages lower than the output voltage, including negative voltages, without reverse current flow from output to input. This makes the LT1521 series ideal for backup power situations where the output is held high and the input is low or reversed. Under these conditions only 5uA will flow from the output pin to ground.
MS-8,SO-8,SOT-223
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT1521CMS8#PBF | MSOP | 8 | C | $2.65 | $2.20 |
| LT1521CMS8-3#PBF | MSOP | 8 | C | $2.65 | $2.20 |
| LT1521CMS8-3#TRPBF | MSOP | 8 | C | $2.26 | |
| LT1521CMS8-3.3#PBF | MSOP | 8 | C | $2.65 | $2.20 |
| LT1521CMS8-3.3#TRPBF | MSOP | 8 | C | $2.26 | |
| LT1521CMS8-5#PBF | MSOP | 8 | C | $2.65 | $2.20 |
| LT1521CS8#PBF | SO | 8 | C | $2.75 | $2.20 |
| LT1521CS8#TRPBF | SO | 8 | C | $2.26 | |
| LT1521CS8-3#PBF | SO | 8 | C | $2.75 | $2.20 |
| LT1521CS8-3#TRPBF | SO | 8 | C | $2.26 | |
| LT1521CS8-3.3#PBF | SO | 8 | C | $2.75 | $2.20 |
| LT1521CS8-3.3#TRPBF | SO | 8 | C | $2.26 | |
| LT1521CS8-5#PBF | SO | 8 | C | $2.75 | $2.20 |
| LT1521CS8-5#TRPBF | SO | 8 | C | $2.26 | |
| LT1521CST-3#PBF | SOT | 3 | C | $2.36 | $1.90 |
| LT1521CST-3#TRPBF | SOT | 3 | C | $1.96 | |
| LT1521CST-3.3#PBF | SOT | 3 | C | $2.36 | $1.90 |
| LT1521CST-3.3#TRPBF | SOT | 3 | C | $1.96 | |
| LT1521CST-5#PBF | SOT | 3 | C | $2.36 | $1.90 |
| LT1521CST-5#TRPBF | SOT | 3 | C | $1.96 | |
| LT1521IS8#PBF | SO | 8 | I | $3.35 | $2.65 |
| LT1521IS8#TRPBF | SO | 8 | I | $2.71 | |
| LT1521IS8-3#PBF | SO | 8 | I | $3.35 | $2.65 |
| LT1521IS8-3#TRPBF | SO | 8 | I | $2.71 | |
| LT1521IS8-3.3#PBF | SO | 8 | I | $3.35 | $2.65 |
| LT1521IS8-3.3#TRPBF | SO | 8 | I | $2.71 | |
| LT1521IS8-5#PBF | SO | 8 | I | $3.35 | $2.65 |
| LT1521IS8-5#TRPBF | SO | 8 | I | $2.71 | |
| LT1521IST-3#PBF | SOT | 3 | I | $3.15 | $2.55 |
| LT1521IST-3#TRPBF | SOT | 3 | I | $2.61 | |
| LT1521IST-3.3#PBF | SOT | 3 | I | $3.15 | $2.55 |
| LT1521IST-3.3#TRPBF | SOT | 3 | I | $2.61 | |
| LT1521IST-5#PBF | SOT | 3 | I | $3.15 | $2.55 |
| LT1521IST-5#TRPBF | SOT | 3 | I | $2.61 | |
| LT1521CMS8 | MSOP | 8 | C | $5.30 | $4.40 |
| LT1521CMS8-3 | MSOP | 8 | C | $5.30 | $4.40 |
| LT1521CMS8-3#TR | MSOP | 8 | C | $4.52 | |
| LT1521CMS8-3.3 | MSOP | 8 | C | $5.30 | $4.40 |
| LT1521CMS8-3.3#TR | MSOP | 8 | C | $4.52 | |
| LT1521CMS8-5 | MSOP | 8 | C | $5.30 | $4.40 |
| LT1521CS8 | SO | 8 | C | $5.50 | $4.40 |
| LT1521CS8#TR | SO | 8 | C | $4.52 | |
| LT1521CS8-3 | SO | 8 | C | $5.50 | $4.40 |
| LT1521CS8-3#TR | SO | 8 | C | $4.52 | |
| LT1521CS8-3.3 | SO | 8 | C | $5.50 | $4.40 |
| LT1521CS8-3.3#TR | SO | 8 | C | $4.52 | |
| LT1521CS8-5 | SO | 8 | C | $5.50 | $4.40 |
| LT1521CS8-5#TR | SO | 8 | C | $4.52 | |
| LT1521CST-3 | SOT | 3 | C | $4.72 | $3.80 |
| LT1521CST-3#TR | SOT | 3 | C | $3.92 | |
| LT1521CST-3.3 | SOT | 3 | C | $4.72 | $3.80 |
| LT1521CST-3.3#TR | SOT | 3 | C | $3.92 | |
| LT1521CST-5 | SOT | 3 | C | $4.72 | $3.80 |
| LT1521CST-5#TR | SOT | 3 | C | $3.92 | |
| LT1521IS8 | SO | 8 | I | $6.70 | $5.30 |
| LT1521IS8#TR | SO | 8 | I | $5.42 | |
| LT1521IS8-3 | SO | 8 | I | $6.70 | $5.30 |
| LT1521IS8-3#TR | SO | 8 | I | $5.42 | |
| LT1521IS8-3.3 | SO | 8 | I | $6.70 | $5.30 |
| LT1521IS8-3.3#TR | SO | 8 | I | $5.42 | |
| LT1521IS8-5 | SO | 8 | I | $6.70 | $5.30 |
| LT1521IS8-5#TR | SO | 8 | I | $5.42 | |
| LT1521IST-3 | SOT | 3 | I | $6.30 | $5.10 |
| LT1521IST-3.3 | SOT | 3 | I | $6.30 | $5.10 |
| LT1521IST-3.3#TR | SOT | 3 | I | $5.22 | |
| LT1521IST-5 | SOT | 3 | I | $6.30 | $5.10 |
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.