MIC1232 5V Voltage Supervisor with Manual Reset, Watchdog Timer and Dual Reset Outputs General Description Features The MIC1232 is a low-current microprocessor supervisor Low-current version of for monitoring 5V systems. The device features logic DS1232/MAX1232/TC1232/CAT1232 selectable (TOL) reset thresholds of 5% or 10% of 5V a Low current: 18A (typ), 40A (max) pushbutton reset input (/PBRST) a watchdog timer with Selectable threshold (TOL): 5% or 10% of 5V three-state selectable (TD) timeout periods of 150ms, Selectable watchdog timer (TD): 150ms, 600ms, 1.2s 600ms, or 1.2s a fixed reset timeout period of 250ms (min) and active-low open-drain reset (/RST) and active- Power OK/Reset time delay: 250ms (min) high push-pull reset (RST) outputs. The /RST output Debounced pushbutton reset input (/PBRST) maintains a valid reset condition for V as low as 1.4V. CC Dual complementary reset outputs The MIC1232 asserts a reset condition if the supply Active-low, open-drain reset output voltage drops below the reset threshold, the pushbutton Active-high, push-pull reset output reset is asserted low, or the watchdog timer does not see Available in Pb-Free 8-pin SOIC and PDIP packages a high-to-low transition on the watchdog timer input within the watchdog timer period. A reset condition is held for the 40C to +85C temperature range reset timeout period of 250ms (min) after the pushbutton Pin-for-Pin compatible with MIC1832/DS1832/CAT1832 input is released or after the supply voltage increases above the reset threshold voltage. Applications The MIC1232 is a drop-in replacement for the DS1232, MAX1232, and TC1232. It consumes a low 18A (typ) of Automotive systems supply current, 40A (max). This is one-tenth the max Intelligent systems current of the DS1232, and one-quarter the max current of Critical microprocessor power monitoring the MAX1232 and TC1232. It operates over the 40C to Battery powered computers +85C temperature range and is available in the Pb-Free 8-pin SOIC and PDIP packages. Controllers Data sheets and support documentation can be found on 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. MIC1232 Ordering Information Part Number Temperature Range Package Lead Finish MIC1232NY 40 to +85C 8-Pin PDIP Pb-Free MIC1232MY 40 to +85C 8-Pin SOIC Pb-Free Pin Configuration 8-Pin PDIP 8-Pin SOIC Pin Description Pin Number Pin Name Pin Function 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 1 /PBRST /PBRST pin are ignored any pulse with a duration of 20ms or greater is guaranteed to cause a reset. Time Delay input: This input selects the timebase used by the watchdog timer. When TD = 0V, the 2 TD 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 Tolerance Select input: This input selects whether 5% or 10% of V is used as the reset threshold CC 3 TOL voltage. When TOL = 0V, the 5% tolerance level is selected and when TOL = V , a 10% tolerance CC level is selected. 4 GND IC ground pin, 0V reference. RST is asserted high if either V goes below the reset threshold, the watchdog times out, or CC 5 RST /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 /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 6 /RST after V exceeds the reset threshold, after the watch times out, or after /PBRST goes high. Open- CC drain output. Input to watchdog timer. If /ST does not see a transition from high to low within the watchdog 7 /ST timeout period, RST and /RST will be asserted. 8 VCC Primary supply input, +5V. M9999-020413 February 2013 2