MIC2755 Battery Operated Supervisor General Description Features The MIC2755 is composed of multiple comparators, a Optimized for PDAs, pagers, and other handheld reset pulse generator, and logic. It is designed for devices monitoring the battery supply of portable digital systems, Detects multiple battery states: including PDAs and pagers. Battery OK The MIC2755 can detect three different battery states: Low battery battery OK, low battery, and dead battery. The reset Dead battery (/RST) output is asserted for at least 700ms when a fresh battery is inserted. The non-maskable interrupt output Adjustable voltage thresholds (/NMI) is asserted when the battery voltage is below the High accuracy 2% voltage thresholds NTH threshold, indicating that high-power system Reset generation at power-on (700ms min.) operations should not occur. If and when battery voltage Debounced manual reset function falls below the power-off threshold (PTH), the reset output Internal logic prevents chatter if battery voltage is asserted and latched, inhibiting system operation until fluctuates the battery is replaced or recharged. Extremely low 2A typical supply current All three voltage thresholds are set using external resistors. A manual reset function can be implemented by I/Os can be pulled above VDD (7V absolute maximum) connecting a switch directly to the power on reset/manual Immune to brief power supply transients reset RTH(/MR) input. Internal circuitry detects switch Low cost activation and generates a minimum 175ms debounced 8-pin MSOP reset signal. The MIC2755s power supply input is separate from the detector inputs to allow it to be powered from a down-stream voltage, such as the output of a boost converter. Inputs and outputs can be pulled above VDD (up to 7V absolute maximum) without adverse effects or excessive current draw. Supply current is typically a low 2A. Hysteresis is included on all voltage detectors to prevent chattering due to noise. The MIC2755 is available in the tiny 8-pin micro- small-outline package. Datasheets and support documentation are available on Micrels web site at: www.micrel.com. Typical Application Supervised Boost Converter and Microcontroller or Microprocessor Micrel Inc. 2180 Fortune Drive San Jose, CA 95131 USA tel +1 (408) 944-0800 fax + 1 (408) 474-1000 Micrel, Inc. MIC2755 Ordering Information Part Number Junction Temperature Range Lead Finish Package MIC2755YMM 40C to +85C Pb-Free 8-Pin MSOP Pin Configuration 8-Pin MSOP (MM) (Top View) Pin Description Pin Number Pin Name Pin Function Power-On Reset Threshold (Analog Input). Comparator input assigned to battery-OK condition 1 RTH(/MR) detection. When the level on this pin first exceeds V , the reset generator cycles. The /RST REF output is held low for a minimum of 700ms and the /POF threshold output is de-asserted. Non-maskable Interrupt Threshold (Analog Input). Voltage monitor input assigned to low battery 2 NTH condition detection. When the level on this pin falls below V , the /NMI output is asserted. REF Power-Off Threshold (Analog Input). Voltage monitor input assigned to dead battery condition 3 PTH detection. When the level on this pin falls below VREF, the /RST and /POF outputs are asserted. The condition is latched until a reset cycle occurs (V > V ). RTH REF 4 GND Ground. Power and signal return for all IC functions. Power-Off (Output). Active-low, open-drain output. Asserted and latched when V < V , which PTH REF 5 /POF is a dead battery condition. Non-maskable Interrupt (Output). Active-low, open-drain output. Asserted when V < V , PTH REF 6 /NMI which is a low battery condition. This indicates high-power system operation should not be allowed. Reset (Output). Active-low, open-drain output. Asserted for a minimum of 700ms at power-on or 7 /RST anytime V drops below V . Also asserted for 175ms minimum when RTH (/MR) is externally PTH REF pulled low (manual reset). 8 VDD Analog Input. Power supply input. May 21, 2015 Revision 2.0 2