DocumentationDatasheet
Reliability Data
LT Journal
cad_symbol
Features
- 350mA Constant Current Output
- 2.8V to 4V Output Compliance
- 1- or 2-Cell NiMH or Alkaline Input
- Synchronous Rectification: Up to 90% Efficiency
- Fixed Frequency Operation: 1.3MHz
- Low Quiescient Current: <1mA
- Very Low Shutdown Current: <50µA
- Open LED Output Limited to 4.7V
- VIN Range: 1V to 3.2V
- Dimming Control
- Undervoltage Lockout to Protect Batteries
- Low Profile (0.75mm) 3mm × 3mm Thermally Enhanced 8-Lead DD and S8 Packages
Typical Application
Description
The LTC3490 provides a constant current drive for 1W LED applications. It is a high efficiency boost converter that operates from 1 or 2 NiMH or alkaline cells and generates 350mA of constant current with up to 4V of compliance. It contains a 100m Ohm NFET switch and a 130m Ohm PFET synchronous rectifier. The fixed switching frequency is internally set to 1.3MHz.The LTC3490 limits the output voltage to 4.7V if the output load is disconnected. It also features an analog dimming capability that reduces the drive current proportional to the CTRL/SHDN pin voltage. A low-battery logic output signals when the battery has dropped below 1V/cell. An undervoltage lockout circuit shuts down the LTC3490 when the battery voltage drops below 0.85V/cell. The feedback loop is internally compensated to minimize component count.
3x3 DFN-8,SO-8
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC3490EDD#PBF | DFN | 8 | E | $3.00 | $2.10 |
| LTC3490EDD#TRPBF | DFN | 8 | E | $2.20 | |
| LTC3490ES8#PBF | SO | 8 | E | $3.00 | $2.10 |
| LTC3490ES8#TRPBF | SO | 8 | E | $2.16 | |
| LTC3490EDD | DFN | 8 | E | $6.00 | $4.20 |
| LTC3490EDD#TR | DFN | 8 | E | $4.40 | |
| LTC3490ES8 | SO | 8 | E | $6.00 | $4.20 |
| LTC3490ES8#TR | SO | 8 | E | $4.32 |
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 |
|---|---|---|---|
| DC762A | LTC3490EDD Demo Board | Boost White LED Driver, 1.8V ≤ VIN ≤ 3.5V, VLED up to 4V @ 350mA | Contact Factory |