ADVANCE INFORMATION All information in this data sheet is preliminary and subject to change. 7/94 MAXUM High-Accuracy, + 1%, Low-Power, +3V and +5V General Description The MAX814/MAX815/MAX816 high-accuracy micro- processor (uP) supervisory circuits reduce the complexity and number of components required to monitor power- supply and battery functions in uP systems. They elimi- nate manual trimming and improve reliability in critical applications needing high-accuracy reset trip thresholds. All members of this device family provide the following three functions: 1) Active-low RESET output, asserted during power-up, power-down, and brownout conditions. The reset threshold is accurate to +1%, over temperature. 2) Threshold detector for power-fail warning, low-battery detection, or monitoring another power-supply voltage. 3) Active-low manual-reset input. Additional device functions are listed below. MAX814: 1) Choice of reset thresholds: 4.8V, 4.7V, 4.55V, or 3.03V. 2) Active-high RESET output. 3) Two-stage power-fail warning. A separate low-line comparator compares Vcc to a threshold 6OmV above the reset threshold. This low-line comparator is more accurate than those in previous wP supervisors, and facilitates early warning of power failure so the system can be put into a safe condition before reset is assert- ed. MAX815: 1) Choice of reset thresholds: 4.8V, 4.7V, 4.55V, or 3.03V. 2) Independent watchdog output that goes low if the watchdog input has not been toggled within 1.56sec. MAX816: 1) Active-high RESET output. 2) Adjustable reset threshold, set with an external resistor divider. In this device, the voltage on the RESET IN pin is monitored, not the voltage on Vcc. The RESET output is guaranteed to be in the correct state for Vcc down to 1V. The reset comparator is designed to ignore fast transients on Vcc. Reset thresholds suitable for operation with a variety of 3V and 5V supply voltages are available. A 75uA max supply current makes the MAX814/ MAX815/MAX816 ideal for use in portable equipment. All three devices are available in 8-pin DIP and SO packages. Typical Operating Circuit on next page. MAXIM uP Supervisory Circuits Features # +1% Reset Threshold Accuracy over Temperature @ 4.8V, 4.7V, 4.55V, 3.03V, or Adjustable Reset Thresholds @ +1% Low-Line Threshold Accuracy (MAX814) # 200ms Reset Pulse Width Active-Low RESET Output Active-High RESET Output (MAX814/MAX816) 75u.A Max Supply Current Guaranteed RESET Valid to Vcc = 1V Manual Reset input Voltage Monitor for Power-Fail or Low-Battery Warning @ Independent Watchdog (MAX815) with 1.56sec Timeout * Power-Supply Glitch Immunity 8-Pin SO and DIP Packages ee Applications Computers Controllers Intelligent Instruments Critical wP Power Monitoring Portable/Battery-Powered Equipment Pin Configurations TOP VIEW I a [71] 8] neseT Vee [Z| MAAXUMA 7 | ESET GND GB] MAX814 4 COWUNE eri [4 [5] FF DIP/SO 7 wT wm C1] 8) woo Voc [2] AAAXIAA 7] fest evo) MO FE wo pri [4] BE DIP/SO MAX816 on next page. Cali toll free 1-800-998-8800 for free samples or literature. 9LEXVW/SESXVW/PLSEXUN Maxim Integrated Products 5-73MAX814/MAX815/MAX816 High-Accuracy, + 1%, Low-Power, +3V and +5V uP Supervisory Circuits Typical Operating Circuit * tT ] #12V SUPPLY Yoo Voc RESET >| RB MAAXLAA MAXB14 wP COW LINE >) NMI PFI PFO $e} INTERRUPT MR GND RESET /}-- GNO Pin Configurations (continued) TOP VIEW Nw ime 11] [8] Reser veo [2] an 7] RESET ono [3] [ | RESET IN PFI [4 [5] PFO DIP/SO 5-74 MAAXLAA