DS1848 Dual Temperature-Controlled NV Variable Resistor & Memory www.maxim-ic.com PIN ASSIGNMENT FEATURES Two linear taper, temperature-controlled variable resistors SDA 1 14 Vcc DS1848-050 SCL 2 13 H0 One 50k , 256 position A0 3 12 NC One 10k , 256 position A1 4 11 H1 DS1848-010 A2 5 10 L1 Two 10k , 256 position WP 6 9 NC Resistor settings changeable every 2C GND 7 8 L0 Access to temperature data and device control via a 2-wire interface 14-Pin TSSOP (173-mil) Operates from 3V or 5V supplies Packaging: 14-pin TSSOP, 16-ball CSBGA Operating temperature: -40C to +95C Top View Programming temperature: 0C to +70C 128 bytes of user EEPROM A B C D 1 2 3 4 16-Ball CSBGA (4mm x 4mm) DESCRIPTION The DS1848 Dual Temperature-Controlled Nonvolatile (NV) Variable Resistor consists of two 256- position linear, variable resistors. The DS1848-050 consists of one 10k and one 50k while the DS1848-010 consists of two 10k resistors both incorporate a direct-to-digital temperature sensor. The device provides an ideal method for setting and temperature-compensating bias voltages and currents in control applications using a minimum of circuitry. The variable resistors settings are stored in EEPROM memory and can be accessed over the industry standard 2-wire serial bus. The value of each variable resistor is determined by a temperature-addressed look-up table, which can assign a unique value to each resistor for every 2C increment over the -40C to +95C range. The output of the digital temperature sensor is also available as a 13-bit, 2s complement value over the serial bus. The interface I/O pins consist of SDA and SCL. 1 of 17 011806 DS1848 PIN DESCRIPTIONS Name TSSOP BGA Description V 14 A3 Power Supply Terminal. The DS1848 will support supply CC voltages ranging from +3.0V 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 DS1848. 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 DS1848 on rising edges and clock data out on falling edges. WP 6 C1 Write Protect Input. If open or set to logic 1, all memory, control registers, and Look-up tables are write protected. If set to a logic 0, the device is not write protected and can be written to. 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 DS1848 when used in a multi-dropped configuration. A1 4 B1 Address Input. A2 5 C2 Address Input. H0 13 A4 High terminal of Resistor 0. For both resistors, 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 resistor cannot exceed V , or go below ground. CC H1 11 B3 High terminal of Resistor 1. L0 8 D3 Low terminal of Resistor 0. For both resistors, 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 resistor cannot exceed V , or go below ground. CC L1 10 C4 Low terminal of Resistor 1. NC 9 D4 No Connect. NC 12 B4 No Connect. NC C3 No Connect. NC D2 No Connect. 2 of 17