LTC3550 - Dual Input USB/AC Adapter Li-Ion Battery Charger with 600mA Buck Converter
Features
- Charges Single-Cell Li-Ion Battery from Wall Adapter and USB Inputs
- Automatic Input Power Detection and Selection
- Charge Current Programmable Up to 950mA from Wall Adapter Input
- Adjustable Output, High Efficiency 600mA Synchronous DC/DC Converter
- No External MOSFET, Sense Resistor or Blocking Diode Needed
- Thermal Regulation Maximizes Charge Rate Without Risk of Overheating
- Preset Charge Voltage with ±0.6% Accuracy
- Programmable Charge Current Termination
- 1.5MHz Constant Frequency Operation (Step-Down Converter)
- 18μA USB Suspend Current in Shutdown
- “Power Present” Status Output
- Charge Status Output
- Automatic Recharge
- Available in a Thermally Enhanced, Low Profile (0.75mm) 16-Lead (5mm × 3mm) DFN Package
Typical Application
Description
The LTC3550 is a standalone linear charger with a 600mA monolithic synchronous buck converter. It is capable of charging a single-cell Li-Ion battery from both wall adapter and USB inputs. The charger automatically selects the appropriate power source for charging.
Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The float voltage is fixed at 4.2V and the charge currents are programmed with external resistors. The LTC3550 terminates the charge cycle when the charge current drops below the programmed termination threshold after the final float voltage is reached. With power applied to both inputs, the LTC3550 can be put into shutdown mode reducing the DCIN supply current to 20μA, the USBIN supply current to 10μA, and the battery drain current to less than 2μA.
The DC/DC converter switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.
| Vout | |
|---|---|
| LTC3550 | Adjustable |
| LTC3550-1 | 1.875V |
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LTC3550EDHC#PBF | 5x3 DFN-16 | DHC | E | 05-08-1706 | Yes |
| LTC3550EDHC#TRPBF | 5x3 DFN-16 | DHC | E | 05-08-1706 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LTC3550EDHC#PBF | 5x3 DFN-16 | E | $2.86 | $2.00 | Yes | |
| LTC3550EDHC#TRPBF | 5x3 DFN-16 | E | $2.06 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
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 |
|---|---|---|---|
| DC1068A | LTC3550EDHC | Dual Input USB/AC Adaptor Battery Charger and 600mA Synchronous Step-Down Converter | $150.00 | |
| Buy Now | |||
Applications
- Cellular Telephones
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Design Tools
LTspice
LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice
Models for the following parts are available in LTspice:
LTC3550
LTC3550-1
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
