DS1846 NV Tri-Potentiometer, Memory, and MicroMonitor www.maxim-ic.com FEATURES PIN CONFIGURATION Three linear taper potentiometers Two 10k , 100-position SDA V 20 1 CC One 100k , 256-position SCL 19 IN 2 248 bytes of user EEPROM memory 18 A0 3 PBRST Monitors microprocessor power supply, WP 4 17 RST voltage sense, and external override 16 RST NMI 5 Access to data and potentiometer control 15 H0 L0 6 through a 2-wire interface 14 W0 External write-protect (WP) pin to protect W1 7 data and potentiometer settings L1 8 13 H1 Operates from a 5V supply W2 L2 9 12 Nonvolatile (NV) wiper storage 10 H2 GND 11 Packaging: 20-pin TSSOP 20-Pin TSSOP Programming temperature: 0C to +70C Industrial operating temperature: PIN DESCRIPTION -40C to +85C V Power-Supply Input CC GND Ground ORDERING INFORMATION SDA 2-Wire Serial Data Input/Output DS1846E-010 SCL 2-Wire Serial Clock Input DS1846E-010/T&R (Tape-and-Reel Version) WP Write-Protect Input A0 Address Input H0, H1, H2 High End of Potentiometer L0, L1, L2 Low End of Potentiometer W0, W1, W2 Wiper Terminal of Potentiometer PBRST Pushbutton Reset Input NMI Nonmaskable Interrupt Output IN NMI Voltage Input RST Active-Low Reset Output RST Active-High Reset Output OVERVIEW The DS1846 NV tri-potentiometer, memory, and MicroMonitor consists of two 10k 100-position linear taper potentiometers, one 100k 256-position linear taper potentiometer 256 bytes of EEPROM memory and a MicroMonitor. The device provides an ideal method for setting bias voltages and currents in control applications using a minimum of circuitry. 1 of 18 042902 MicroMonitor is a trademark of Dallas Semiconductor.DS1846 The EEPROM memory allows a user to store configuration or calibration data for a specific system or device and provides control of the potentiometer wiper settings. Any type of user information can reside in the first 248 bytes (00h to F7h) of this memory. The next three bytes of memory (F8h to FAh) are for potentiometer settings and the last five addresses of EEPROM memory (FBh to FFh) are reserved. These reserved and potentiometer registers should not be used for data storage. Access to this EEPROM is through an industry-standard 2-wire bus. The interface I/O pins consist of SDA and SCL. The wiper positions of the DS1846, as well as EEPROM data, can be hardware write-protected using the WP input pin. The MicroMonitor is a precision temperature-compensated reference and comparator that monitors certain vital status conditions for a microprocessor. When a sense input detects an out-of-tolerance (V ) CC condition, a nonmaskable interrupt is generated. As the voltage at the device degrades, an internal power- fail signal is generated that can be used to reset the processor. When V returns to an in-tolerance level, CC the reset signal is kept in the active state for a minimum time of t to allow for the stabilization of the RST power supply and the microprocessor. The MicroMonitor also functions as a pushbutton reset control. The pushbutton input is debounced internally and generates an active pulse width of t minimum. RST DS1846 BLOCK DIAGRAM Figure 1 DS1846 EEPROM Potentiometer 2 SCL 10k H2 5 Reserved Data SDA 2-Wire Addr FAh W2 Bytes WP Interface 100-Positions L2 FBh-FFh A0 Potentiometer 2 Potentiometer 0 10k H0 FAh Addr F9h W0 100-Positions L0 Potentiometer 0 F9h Potentiometer 1 Potentiometer 1 100k H1 F8h Addr F8h W1 256-Positions L1 User EPROM 248 Bytes Nonvolatile 00h-F7h Digital Potentiometer V CC MicroMonitor R PBR PBRST RST V CC Timer RST Delay V V CCTP CC IN Timer 2.4k Delay typical V TP NMI 2 of 18