High Voltage Regulator Aids Battery Chargers

Linear Technology’s LT3653 is a 1.2-A, 1.5-MHz current-mode stepdown regulator that is typically used with battery charger power path controllers to pre-regulate the output and optimize battery charger efficiency. Its 7.5-V to 30-V input voltage range makes the LT3653 ideal for a variety of input power sources (see the figure).

Device type: buck regulator
Input voltage range: 7.5 V to 30 V
Output voltage: nominal setpoint is 4.8 V typical
Output current: 1.2 A
Quiescent current: VIN supply current is 3.4 mA max when not switching
Efficiency: Peak efficiency is approximately 85% at VIN = 12 V
Features: VC control pin is available for external battery tracking (known as Bat-Track control), which keeps the output voltage only 300 mV above the Li-Ion battery voltage; adjustable output current limit can be set between 400 mA and 1.2 A via an external resistor; input overvoltage lockout protects the device through input transients as high as 60 V; chip does not allow reverse discharge from the battery to VIN, eliminating the need for a blocking FET; switching frequency is 1.5 MHz; chip also has internal compensation and an internal boost diode; industrial-grade version is tested and guaranteed to operate over -40°C to 125°C operating junction temperature range
Operating temperature range: -40°C to +125°C
Packaging: 2-mm x 3-mm DFN
RoHS compliant? leadfree
Target applications: unregulated 12-V wall adapters, 24-V industrial supplies and Firewire as well as automotive applications
Pricing: starts at $2.50 each for 1000-piece quantities, $2.88 each for industrial-grade version
Availability: available now