DESCRIPTION

· The RT9709 is an integrated over-voltage protection circuit designed to safeguard low-voltage systems from abnormal high-voltage inputs up to 28V.
· It monitors input voltage, battery voltage, and charging current to ensure normal operation.
· The IC also monitors its own temperature and turns off the MOSFET when the chip temperature exceeds 140°C.
· It supports both AC and USB chargers.
· The MOSFET is turned off within 1us when the input voltage exceeds the OVP threshold.
· The current in the MOSFET is limited to prevent excessive battery charging.
· The OCP function includes a 4-bit binary counter that accumulates during an OCP event, turning off the MOSFET permanently after 16 counts unless the input power is recycled.
· The IC monitors the battery voltage VB and turns off the MOSFET if it exceeds 4.4V for more than 180us.
· The internal logic control latches the MOSFET off after 16 battery over-voltage events.

FEATURES

· Fully integrated protection circuit for three protection variables.
· User-programmable OCP threshold.
· Input OVP response in less than 1us.
· Battery OVP.
· Up to 30V over-voltage protection.
· High accuracy protection threshold.
· High immunity to false triggering under transients.
· Warning indication output.
· Enable input.
· Thermally enhanced WDFN package.
· RoHS compliant and halogen-free.

APPLICATIONS

· Cellular phones.
· Digital cameras.
· PDAs and smartphones.
· Portable instruments.