DS1845 Dual NV Potentiometer and Memory www.maxim-ic.com FEATURES Two linear taper potentiometers SDA 1 14 Vcc DS1845-010 one 10k, 100 position & SCL 2 13 H0 one 10k, 256 position A0 3 12 W1 DS1845-050 one 10k, 100 position & A1 4 11 H1 one 50k, 256 postition A2 5 10 L1 DS1845-100 one 10k, 100 position & one 100k, 256 position WP 6 9 W0 256 bytes of EEPROM memory GND 7 8 L0 Access to data and potentiometer control via 2 an I C compatible 2-wire interface 14-Pin TSSOP (173 mil) External Write Enable pin to protect data and Top View potentiometer settings Nonvolatile wiper storage A Operates from 3V or 5V supplies Packaging: Flip Chip Package, 16-ball B CSBGA, 14-pin TSSOP C Industrial operating temperature: -40C to +85C D 1 2 3 4 16-Ball CSBGA (4mm x 4mm) 14-Pin Flip Chip (100-mil x 100-mil) (Not Shown) DESCRIPTION The DS1845 Dual NV Potentiometer and Memory consists of one 100-position linear taper potentiometer, one 256-position linear taper potentiometer, 256 bytes of EEPROM memory, and a 2-wire interface. The device provides an ideal method for setting bias voltages and currents in control applications using a minimum of circuitry. The EEPROM memory allows a user to store configuration or calibration data for a specific system or device as well as provide control of the potentiometer wiper settings. Any type of user information may reside in the first 248 bytes of this memory. The next two addresses of EEPROM memory are for potentiometer settings. Access to this EEPROM is via an industry standard 2-wire bus. The wiper position of the DS1845, as well as EEPROM data, can be hardware write-protected using the Write Protect (WP) input pin. Up to eight DS1845s can be installed on a single 2-wire bus. Access to an individual device is achieved by using a device address that is determined by the logic levels of address pins A0 though A2. Additionally, the DS1845 will operate from 3 volt or 5 volt supplies. Three package options are available: Flip Chip Package, 16-ball CSBGA and 14-pin TSSOP. 1 of 14 011006 DS1845 PIN DESCRIPTIONS Name TSSOP BGA Description V 14 A3 Power Supply Terminal. The DS1845 will support supply CC voltages ranging from +2.7V to +5.5V. GND 7 D1 Ground Terminal. SDA 1 B2 2-Wire serial data interface. The serial data pin is for serial data transfer to and from the DS1845. The pin is open drain and may be wire-ORed with other open drain or open collector interfaces. SCL 2 A2 2-Wire Serial Clock Input. The serial clock input is used to clock data into the DS1845 on rising edges and clock data out on falling edges. WP 6 C1 Write Protect Input. If set to logic 0, the data in memory and the potentiometer wiper setting may be changed. If set to logic 1, both the memory and the potentiometer wiper settings will be write protected. The WP pin is pulled high internally. A0 3 A1 Address Input. Pins A0, A1, and A2 are used to specify the address of each DS1845 when used in a multi-dropped configuration. Up to eight DS1845s may be addressed on a single 2-wire bus. A1 4 B1 Address Input. A2 5 C2 Address Input. H0 13 A4 High terminal of Potentiometer 0. For both potentiometers, it is not required that the high terminal be connected to a potential greater than the low terminal. Voltage applied to the high terminal of each potentiometer cannot exceed V or go below ground. CC H1 11 B3 High terminal of Potentiometer 1. L0 8 D3 Low terminal of Potentiometer 0. For both potentiometers, it is not required that the low terminal be connected to a potential less than the high terminal. Voltage applied to the low terminal of each potentiometer cannot exceed V or go below ground. CC L1 10 C4 Low terminal of Potentiometer 1. W0 9 D4 Wiper terminal of Pot 0. The wiper position of Potentiometer 0 is determined by the byte at EEPROM memory location F9h. Voltage applied to the wiper terminal of each potentiometer cannot exceed the power supply voltage, V , or go below ground. CC W1 12 B4 Wiper terminal of Pot 1. The wiper position of Potentiometer 1 is determined by the byte at EEPROM memory location F8h. NC C3 No Connect. NC D2 No Connect. 2 of 14