UC3730 Datasheet | Unitrode

FEATURES - - - - - - On-Chip Temperature Transducer Temperature parator Gives Threshold Temperature Alarm Power Reference Permits Airflow Diagnostics Precision 2.5V Power Reference Permits Airflow Diagnostics Transducer Output is Easily Scaled for Increased Sensitivity Low 2.5m A Quiescent Current DESCRIPTION The UC1730 family of integrated circuit devices are designed to be used in a number of thermal monitoring applications. Each IC bines a temperature transducer, precision reference, and temperature parator allowing the device to respond with a logic output if temperatures exceed a user programmed level. The reference on these devices is capable of supplying in excess of 250m A of output current - by setting a level of power dissipation the rise in die temperature will vary with airflow past the package, allowing the IC to respond to airflow conditions These devices e in an 8-Pin DIP, plastic or ceramic, a 5-Pin TO-220 or a PLCC-20 version. In the 8-Pin version, a PTAT (proportional to absolute temperature) output reports die temperature directly. This output is configured such that its output level can be easily scaled up with two external gain resistors. A second PTAT source is internally referenced to the temperature parator. The other input to this parator can then be externally programmed to set a temperature threshold. When this temperature threshold is exceeded an alarm delay output is activated. Following the activation of the delay output, a separate open collector output is turned on. The delay pin can be programmed with an external RC to provide a time separation between activation of the delay pin and the alarm pin, permitting shutdown diagnostics in applications where the open collector outputs of multiple parts are wire OR’ed together. The 5-Pin version in the TO-220 package is well suited for monitoring heatsink temperatures. Enhanced airflow sensitivities can be obtained with this package by mounting the device to a small heatsink in the...