TPS3707-33 Status: ACTIVE

Product Information

Features

• Power-On Reset Generator with Fixed Delay Time of 200 ms, no External Capacitor Needed
• Precision Supply Voltage Monitor 2.5 V, 3 V, 3.3 V, and 5 V
• Pin-For-Pin Compatible with the MAX705 through MAX708 Series
• Integrated Watchdog Timer (TPS3705 only)
• Voltage Monitor for Power-Fail or Low-Battery Warning
• Maximum Supply Current of 50 µA
• MSOP-8 and SO-8 Packages
• Temperature Range . . . –40°C to 85°C

typical applications

• Designs Using DSPs, Microcontrollers or Microprocessors
• Industrial Equipment
• Programmable Controls
• Automotive Systems
• Portable/Battery Powered Equipment
• Intelligent Instruments
• Wireless Communication Systems
• Notebook/Desktop Computers

Description

The TPS3705, TPS3707 family of microprocessor supply-voltage supervisors provide circuit initialization and timing supervision, primarily for DSP and processor-based systems.

During power-on, RESET\ is asserted when the supply voltage V_DD becomes higher than 1.1 V. Thereafter, the supply voltage supervisor monitors V_DD and keeps RESET\ active as long as V_DD remains below the threshold voltage V_IT+. An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time, t_dtyp = 200 ms, starts after V_DD has risen above the threshold voltage V_IT+. When the supply voltage drops below the threshold voltage V_IT–, the output becomes active (low) again. No external components are required. All the devices of this family have a fixed-sense threshold voltage V_IT– set by an internal voltage divider.

The TPS3705-xx and TPS3707-xx devices incorporate a manual reset input, MR\. A low level at MR\ causes RESET\ to become active.

The TPS370x-xx families integrate a power-fail comparator which can be used for low-battery detection, power-fail warning, or for monitoring a power supply other than the main supply.

The TPS3705-xx devices have a watchdog timer that is periodically triggered by a positive or negative transition at WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval, t_t(out) = 1.6 s, WDO\ becomes active. This event also reinitializes the watchdog timer. Leaving WDI unconnected disables the watchdog.

The TPS3707-xx devices do not have the Watchdog function, but include a high-level output RESET.

The product spectrum is designed for supply voltages of 2.5 V, 3 V, 3.3 V, and 5 V. The circuits are available in either 8-pin MSOP or standard SOIC packages. The TPS3705, TPS3707 devices are characterized for operation over a temperature range of –40°C to 85°C.