APX825A

Description

The APX823/APX824/APX825A family of supervisors provides circuit initialization and timing supervision, primarily for DSP and processor-based systems. During power-on, RESET is asserted when supply voltage V_CC becomes higher than 1.1V. Thereafter, the supply voltage supervisor monitors V_CC and keeps RESET active as long as V_CC remains below the threshold voltage V_TH-. An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time ,td, starts after V_CC has risen above the threshold voltage VTH-. When the supply voltage drops below the threshold voltage V_TH-, the output becomes active (low) again. No external components are required. All the devices of this family have a fixed-sense threshold voltage V_TH- set by an internal voltage divider. The APX823/APX825A devices incorporate a manual reset input, MR. A low level at causes RESET to become active. The APX824/APX825A devices include a high-level output RESET. APX823/APX824/APX825A 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, ttout, RESET becomes active for the time period td. This event also reinitializes the watchdog timer. Leaving WDI unconnected disables the watchdog. In applications where the input to the WDI pin may be active (transitioning high and low) when the APX823/APX824/APX825A asserting RESET, the APX823/APX824/APX825A does not return to a non-reset state when the input voltage is above Vt. The product spectrum is designed for supply voltage of 2.5V, 3V, 3.3V and 5V. The circuits are available in a SOT25 and SOT26 packages. The APX823/APX824/APX825A devices are characterized for operation over a temperature range of -40°C to 105°C.

Feature(s)

Power-on reset generator with fixed delay time of 200ms Typ

Manual reset input (APX823/APX825A)

Reset output available in active-Low (APX823/APX824/APX825A), active-high (APX824/APX825A)

Supply voltage supervision range 2.5V, 3V, 3.3V, 5V

Watchdog timer

Supply current of 30μA (Typ.)

Temperature range: -40°C to 85°C

SOT25 and SOT26: Available in “Green” Molding Compound (No Br, Sb)

Lead Free Finish/RoHS Compliant

Application(s)

Applications Using DSPs, Microcontrollers, or Microprocessors

Industrial Equipment

Programmable Controls

Automotive Systems

Portable/Battery-Powered Equipment

Intelligent Instruments

Wireless Communications Systems

Notebook/Desktop Computers