DocumentationDatasheet
Application Note
- AN118 - High Voltage, Low Noise, DC/DC Converters
- AN98 - Signal Sources, Conditioners and Power Circuitry Circuits of the Fall, 2004
Design Note
Reliability Data
LT Journal
cad_symbol
ltspice
Features
- Highly Integrated IC Reduces Solution Size
- Uses Small Transformers:
5.8mm x 5.8mm x 3mm - Fast Photoflash Charge Times:
4.6s for LT3468 (0V to 320V, 100µF, VIN = 3.6V)
5.7s for LT3468-2 (0V to 320V, 100µF, VIN = 3.6V)
5.5s for LT3468-1 (0V to 320V, 50µF, VIN = 3.6V) - Controlled Input Current:
500mA (LT3468)
375mA (LT3468-2)
225mA (LT3468-1) - Supports Operation from Single Li-Ion Cell, or Any Supply from 2.5V up to 16V
- Adjustable Output Voltage
- No Output Voltage Divider Needed
- Charges Any Size Photoflash Capacitor
- Low Profile (<1mm) SOT-23 Package
Typical Application
Description
The LT3468/LT3468-1/LT3468-2 are highly integrated ICs designed to charge photoflash capacitors in digital and film cameras. A patented control technique* allows for the use of extremely small transformers. Each device contains an on-chip high voltage NPN power switch. Output voltage detection* is completely contained within the device, eliminating the need for any discrete zener diodes or resistors. The output voltage can be adjusted by simply changing the turns ratio of the transformer. The LT3468 has a primary current limit of 1.4A, the LT3468-2 has a 1A limit, and the LT3468-1 has a 0.7A limit. These different current limit levels result in well controlled input currents of 500mA for the LT3468, 375mA for the LT3468-2 and 225mA for the LT3468-1. Aside from the differing current limit, the three devices are otherwise equivalent.
The CHARGE pin gives full control of the part to the user. Driving CHARGE low puts the part in shutdown. The DONE pin indicates when the part has completed charging. The LT3468 series of parts are available in tiny low profile (1mm) SOT-23 packages.
*Protected by U.S. Patents, including 6518733.
SOT-23
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT3468ES5#TRMPBF | SOT | 5 | E | $2.86 | $2.03 |
| LT3468ES5#TRPBF | SOT | 5 | E | $2.86 | $2.01 |
| LT3468ES5-1#TRMPBF | SOT | 5 | E | $2.86 | $2.03 |
| LT3468ES5-1#TRPBF | SOT | 5 | E | $2.86 | $2.01 |
| LT3468ES5-2#TRMPBF | SOT | 5 | E | $2.86 | $2.03 |
| LT3468ES5-2#TRPBF | SOT | 5 | E | $2.86 | $2.01 |
| LT3468ES5 | SOT | 5 | E | $5.72 | |
| LT3468ES5-1 | SOT | 5 | E | $5.72 | |
| LT3468ES5#TR | SOT | 5 | E | $5.72 | $4.02 |
| LT3468ES5-2 | SOT | 5 | E | $5.72 | |
| LT3468ES5#TRM | SOT | 5 | E | $5.72 | $4.06 |
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.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC661A-A | LT3468ES5 | Photoflash Capacitor Charger High Voltage Supply, 2.8V to 8Vin, 320Vout | $125.00 | |
| DC661A-B | LT3468ES5-1 | Photoflash Capacitor Charger High Voltage Supply, 2.8V to 8Vin, 320Vout | $125.00 | |
| DC711A-A | LT3468ES5 | Photoflash Capacitor Charger High Voltage Supply, Vin = 2.5V-8V, Vout = 320V, ISW - PK = 1.4A | $125.00 | |
| DC711A-B | LT3468ES5-1 | Photoflash Capacitor Charger High Voltage Supply, Vin = 2.5V-8V, Vout = 320V, ISW - PK = 0.7A | $125.00 | |
| DC711A-C | LT3468ES5-2 | Photoflash Capacitor Charger High Voltage Supply, Vin = 2.5V-8V, Vout = 320V, ISW - PK = 1.0A | $125.00 | |
| DC796A | LT3468ES5-1 | Cell Phone Photoflash Charger, Vin(5V max), 2.8V to 4.2V | Contact Factory |