DS1855 DALLAS [Dallas Semiconductor], DS1855 Datasheet
DS1855
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DS1855 Summary of contents
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... The DS1855 dual nonvolatile (NV) digital potentiometer and secure 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 DS1855, which features a new software write protect upgrade of the DS1845. The DS1855 provides an ideal method for setting bias voltages and currents in control applications using a minimum of circuitry ...
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... Ground Terminal. 2-Wire serial data interface. The serial data pin is for serial data transfer to and from the DS1855. The pin is open drain and may be wire-ORed with other open drain or open collector interfaces. 2-Wire Serial Clock Input. The serial clock input is used to clock data into the DS1855 on rising edges and clock data out on falling edges ...
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... eight DS1855s 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 through A2. Additionally, the DS1855 will operate from supplies. Three package options are available: 14- pin TSSOP, 16-ball STPBGA, and flip-chip package. ...
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... MEMORY ORGANIZATION The DS1855’s serial EEPROM is internally organized with 256 words of 1 byte each. Each word requires an 8-bit address for random word addressing. The byte at address F9h determines the wiper setting for potentiometer 0, which contains 100 positions. Writing values above 63h to this address sets the wiper to its uppermost position, but the MSB is ignored ...
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FBh – FCh Lock Bytes FD – FFh Reserved Writing to these two bytes allows the user to lock or unlock the memory described in byte FAh. LOCK: If memory location FBh is written to 56h and memory location FCh ...
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... The master must transmit an 8-bit EEPROM memory address to the device to define the address where the data written. After the reception of this byte, the DS1855 will transmit a zero for one clock cycle to acknowledge the receipt of the address. The master must then transmit an 8-bit data word to be written into this address ...
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... The DS1855 is capable of an 8-byte page write. A page write is initiated the same way as a byte write, but the master does not send a STOP condition after the first byte. Instead, after the slave acknowledges receipt of the data byte, the master can send up to seven more bytes using the same nine-clock sequence. ...
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... The bus must be controlled by a master device that generates the serial clock (SCL), controls the bus access, and generates the START and STOP conditions. The DS1855 operates as a slave on the two-wire bus. Connections to the bus are made via the open-drain I/O lines, SDA and SCL ...
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... Slave transmitter mode: The first byte is received and handled as in the slave receiver mode. However, in this mode the direction bit will indicate that the transfer direction is reversed. Serial data is transmitted on SDA by the DS1855 while the serial clock is input on SCL. START and STOP conditions are recognized as the beginning and end of a serial transfer. ...
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... In addition to the WP pin possible to write-protect, or lock, certain portions of the EEPROM through software control. The DS1855 256-byte EEPROM can be visualized as three blocks, or partitions. The lower block is from 00h to 7Fh. The upper block is 80h to F7h. And the upper page is from F8 to FFh. ...
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PROTOCOL DATA TRANSFER PROTOCOL Figure 2 2-WIRE AC CHARACTERISTICS Figure ...
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... The Dallas Semiconductor DS1855 is built to the highest quality standards and manufactured for long- term reliability. All DS1855s are made using the same quality materials and manufacturing methods. However, the DS1855 in the flip-chip package is not exposed to environmental stresses, such as burn-in, that some industrial applications require. For specific reliability information on this product, please contact the factory in Dallas at (972) 371-4448 ...
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... Cutoff f cutoff Frequency End-to-End Temp. Coefficient CONDITION GND - 3. +25 C ° 10kW/100 pos. 10kW/256 pos. 20kW/256 pos. 50kW/256 pos. 100kW/256 pos. 10kW/100 pos. all other pots DS1855-010 2.7V to 5.5V) CC MIN TYP MAX UNITS V +0.3 CC 0.3 400 1000 250 600 2 -20 +20 -0.75 0.75 -0.75 0.75 -1 ...
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AC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL SCL Clock Frequency Bus Free Time Between STOP and START Hold Time (repeated) START Condition Low Period of SCL Clock High Period of SCL Clock Data Hold Time Data Set-Up Time Start Set-Up Time Rise ...
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NOTES: 1. All voltages are referenced to ground specified with for V STBY logic levels. Appropriate logic levels specify that logic inputs are within a 0.5V of ground or V the corresponding inactive state. 3. I/O pins of ...
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TYPICAL OPERATING CHARACTERISTICS ( +25ºC, unless otherwise specified WIPER RESISTANCE vs. WIPER VOLTAGE 450 400 350 300 250 200 150 100 50 POT 0, ...
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TYPICAL OPERATING CHARACTERISTICS (cont 5V +25ºC, unless otherwise specified) CC END-TO-END RES % CHANGE vs. TEMPERATURE 2.5% 2.0% 1.5% 1.0% 0.5% 0.0% -0.5% -1.0% -1.5% -2.0% -40 - -10 -15 - ...
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TYPICAL OPERATING CHARACTERISTICS (cont 5V +25ºC, unless otherwise specified) CC 150 130 110 RESISTANCE vs. VOLTAGE (POWER-UP) 160,000 140,000 120,000 100,000 80,000 60,000 40,000 20,000 0 0.0 0.5 ACTIVE ...
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TYPICAL OPERATING CHARACTERISTICS (cont 5V +25ºC, unless otherwise specified) CC RESISTANCE vs. VOLTAGE (POWER-DOWN) 70,000 60,000 Pot 1 set to 255 decimal 50,000 40,000 Pot 1 set to 127 decimal 30,000 20,000 Pot 0 set to ...
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... FLIP CHIP DS1855B-020 16-BALL STPBGA (4X4 MM) DS1855E-050 14-PIN TSSOP (173-MIL) DS1855E-050/T&R 14-PIN TSSOP/TAPE & REEL DS1855X-050 14-PIN FLIP CHIP DS1855B-050 16-BALL STPBGA (4X4 MM) DS1855E-100 14-PIN TSSOP (173-MIL) DS1855E-100/T&R 14-PIN TSSOP/TAPE & REEL DS1855X-100 14-PIN FLIP CHIP DS1855B-100 16-BALL STPBGA (4X4 MM) ...