APX823/APX824/APX825A PROCESSOR SUPERVISORY CIRCUITS Description Pin Assignments (Top View) The APX823/APX824/APX825A family of supervisors provides circuit initialization and timing supervision, primarily for DSP and processor-based systems. 5 1 V CC RESET During power-on, is asserted when supply voltage RESET 22 APX823 V becomes higher than 1.1V. Thereafter, the supply GND CC voltage supervisor monitors V and keeps active as RESET CC 3 4 WDI MR long as V remains below the threshold voltage V . An CC TH- internal timer delays the return of the output to the inactive SOT25 state (high) to ensure proper system reset. The delay time, t d starts after V has risen above the threshold voltage V . CC TH- (Top View) When the supply voltage drops below the threshold voltage V , the output becomes active (low) again. No external TH- 1 5 V RESET CC components are required. All the devices of this family have a fixed-sense threshold voltage V set by an internal voltage TH- 22 GND APX824 divider. The APX823/APX825A devices incorporate a manual reset 3 4 WDI RESET input, MR . A low level at MR causes to become RESET active. The APX824/APX825A devices include a high-level SOT25 output RESET. APX823/APX824/APX825A have a watchdog timer that is periodically triggered by a positive or negative (Top View) transition at WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval, 6 1 V ttout, becomes active for the time period td. This RESET CC RESET event also reinitializes the watchdog timer. Leaving WDI 22 APX825A 5 GND WDI unconnected disables the watchdog. In applications where the input to the WDI pin may be active 3 4 RESET MR (transitioning high and low) when the APX823/APX824/APX8 25A asserting the APX823/APX824/APX825A does RESET SOT26 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 o o operation over a temperature range of -40 C to 105 C. Applications Features Applications Using DSPs, Microcontrollers, or Power-on reset generator with fixed delay time of 200ms Microprocessors Typ Industrial Equipment Manual reset input (APX823/APX825A) Programmable Controls Reset output available in active-low Automotive Systems (APX823/APX824/APX825A), active-high Portable/Battery-Powered Equipment (APX824/APX825A) Intelligent Instruments Supply voltage supervision range 2.5V, 3V, 3.3V, 5V Wireless Communications Systems Watchdog timer Notebook/Desktop Computers Supply current of 30A (Typ.) Temperature range: -40C to 85C SOT25 and SOT26: Available in Green Molding Compound (No Br, Sb) Lead Free Finish/RoHS Compliant (Note 1) Note: 1. EU Directive 2002/95/EC (RoHS). All applicable RoHS exemptions applied, see EU Directive 2002/95/EC Annex Notes. 1 of 12 May 2011 APX823/APX824/APX825A Diodes Incorporated www.diodes.com Document number: DS31323 Rev. 4 - 2 APX823/APX824/APX825A PROCESSOR SUPERVISORY CIRCUITS Typical Application Circuit V CC C IN 100nF V V CC CC RESET RESET APX8XX Microprocessor MR WDI I/O GND GND Pin Descriptions Pin Name Description GND Ground RESET Reset output pin (RESET) V Operating voltage input CC WDI Watchdog input Manual reset MR Functional Block Diagram 2 of 12 May 2011 APX823/APX824/APX825A Diodes Incorporated www.diodes.com Document number: DS31323 Rev. 4 - 2