MIC1832 3.3V Voltage Supervisor with Manual Reset, Watchdog Timer and Dual Reset Outputs General Description Features The MIC1832 is a low-current microprocessor supervisor Low-current version of DS1832 for monitoring 3.3V and 3V systems. The device features Low current: 15A (typ), 25A (max) logic-selectable (TOL) reset thresholds of 10% or 20% of Selectable threshold (TOL): 10% or 20% of 3.3V 3.3V a pushbutton reset input a watchdog timer with Selectable watchdog timer (TD): 150ms, 600ms, 1.2s three-state selectable (TD) timeout periods of 150ms, 600ms, or 1.2s a fixed reset timeout period of 250ms Power OK/Reset time delay: 250ms (min) (min) and active-low open-drain reset (/RST) and active- Debounced pushbutton reset input high push-pull reset (RST) outputs. The /RST output Dual complementary reset outputs maintains a valid reset condition for V as low as 1.4V. CC o Active-low, open-drain reset output The MIC1832 asserts a reset condition if the supply o Active-high, push-pull reset output voltage drops below the reset threshold, the pushbutton Available in Pb-Free 8-pin SOIC and PDIP packages reset is asserted low, or the watchdog timer does not see a high-to-low transition on the watchdog timer input within 40C to +85C temperature range the watchdog timer period. A reset condition is held for the Pin-for-Pin compatible with MIC1232/DS1232/CAT1232 reset timeout period of 250ms (min) after the pushbutton input is released, after the supply voltage increases above Applications the reset threshold voltage, or after the watchdog has initiated a reset. Automotive systems The MIC1832 is a drop-in replacement for the DS1832. It Intelligent systems operates over the 40C to +85C temperature range and Critical microprocessor power monitoring is available in Pb-Free 8-pin SOIC and PDIP packages. Battery powered computers Data sheets and support documentation can be found on Controllers Micrels web site at: www.micrel.com. Typical Application Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC1832 Ordering Information Part Number Temperature Range Package Lead Finish MIC1832NY 40 to +85C 8-Pin PDIP Pb-Free MIC1832MY 40 to +85C 8-Pin SOIC Pb-Free Pin Configuration 8-Pin PDIP 8-Pin SOIC Pin Description Pin Number Pin Name Pin Function 1 /PBRST Pushbutton Reset input: This input is debounced and can be driven with external logic signals or by using a mechanical pushbutton to actively force a reset. All pulses less than 1ms in duration on the /PBRST pin are ignored any pulse with a duration of 20ms or greater is guaranteed to cause a reset. 2 TD Time Delay input: This input selects the timebase used by the watchdog timer. When TD = 0V, the watchdog timeout period is set to a normal value of 150ms. When TD = open, the watchdog timeout period is set to a nominal value of 600ms. When TD = V , the watchdog period is 1.2s nominally. CC 3 TOL Tolerance Select input: This input selects whether 10% or 20% of V is used as the reset CC threshold voltage. When TOL = 0V, the 10% tolerance level is selected and when TOL = V , a CC 20% tolerance level is selected. 4 GND IC ground pin, 0V reference 5 RST RST is asserted high if either V goes below the reset threshold, the watchdog times out, or CC /PBRST is pulled low for a minimum of 20ms. RST remains asserted for one reset timeout period after V exceeds the reset threshold, after the watch times out, or after /PBRST goes high. CC 6 /RST /RST is asserted low if either V goes below the reset threshold, the watchdog times out, or CC /PBRST is pulled low for a minimum of 20ms. /RST remains asserted for one reset timeout period after V exceeds the reset threshold, after the watch times out, or after /PBRST goes high. Open- CC drain output 7 /ST Input to watchdog timer. If /ST does not see a transition from high to low within the watchdog timeout period, RST and /RST are asserted. 8 VCC Primary supply input. M9999-020413 February 2013 2