DS1841 Rev 1 3/08 2 Temperature-Controlled, NV, I C, Logarithmic Resistor General Description Features The DS1841 is a 7-bit, logarithmic, nonvolatile (NV) digi- 22k to 3.7k Adjustable Logarithmic Resistor tal resistor that features an on-chip temperature sensor with a 3.6k Fixed Resistor and associated analog-to-digital converter (ADC). The 128 Wiper Tap Points integrated temperature sensor indexes a 72-byte NV On-Chip Temperature Sensor and ADC lookup table (LUT) encompassing a temperature range from -40C to +100C. The LUT output can drive the 72-Byte Lookup Table (LUT) resistor directly or be added to an NV initial-value regis- 2 I C-Compatible Serial Interface ter (IVR) to drive the resistor. This flexible LUT-based Address Pins Allow Up to Four DS1841s to Share architecture allows the DS1841 to provide a tempera- 2 the Same I C Bus ture-compensated resistor output with arbitrary slope. 2 Programming is accomplished by an I C-compatible Digital Supply of 2.7V to 5.5V interface, which can operate at speeds of up to 400kHz. -40C to +100C Operating Range 3mm x 3mm, 10-Pin TDFN Package Applications Optical Transceivers Ordering Information Linear and Nonlinear Compensation PART TEMP RANGE PIN-PACKAGE Instrumentation and Industrial Controls DS1841N+ -40C to +100C 10 TDFN-EP* Mechanical Potentiometer Replacement DS1841N+T&R -40C to +100C 10 TDFN-EP* +Denotes a lead-free package. T&R = Tape and reel. Registers and Modes are capitalized for clarity. *EP = Exposed pad. Typical Operating Circuit Pin Configuration TOP VIEW 3.3V SCL N.C. RH RW RGND 10 9 8 7 6 4.7k V 4.7k APD V OUT SDA V CC SCL 0.1F DC-DC GND CONVERTER DS1841 FB *EP DS1841 RH RW 132 4 5 100pF A1 SDA GND V A1 A0 CC A0 RGND TDFN (3.0mm 3.0mm 0.8mm) APD BIAS CONTROL APPLICATION *EXPOSED PAD Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.2 Temperature-Controlled, NV, I C, Logarithmic Resistor ABSOLUTE MAXIMUM RATINGS Voltage Range on SDA, SCL, and Programming Temperature Range .........................0C to +70C V Relative to GND .........................................-0.5V to +6.0V Storage Temperature Range .............................-55C to +125C CC Voltage Range on RH, RW, A0, and Soldering Temperature .....................See IPC/JEDEC J-STD-020 A1 Relative to GND ................................-0.5V to (V + 0.5V) RW Current............................................................................3mA CC Operating Temperature Range .........................-40C to +100C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (T = -40C to +100C) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V (Note 1) +2.7 +5.5 V CC Input Logic 1 0.7 x V CC V V IH (SCL, SDA, A0, A1) V + 0.3 CC Input Logic 0 0.3 x V -0.3 V IL (SCL, SDA, A0, A1) V CC V CC Resistor Inputs (RW, RH) V -0.3 V RES + 0.5 Wiper Current I 2mA WIPER DC ELECTRICAL CHARACTERISTICS (V = +2.7V to +5.5V, T = -40C to +100C, unless otherwise noted.) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Input Leakage I -1 +1 A L (SDA, SCL, A0, A1) V Supply Current I (Note 2) 350 A CC CC2 Low-Level Output Voltage (SDA) V 3mA sink current 0 0.4 V OL I/O Capacitance C 5 10 pF I/O Power-On Recall Voltage V (Note 3) 1.6 2.6 V POR Power-Up Recall Delay t (Note 4) 5 ms D Series Resistance R 3.6 k S Minimum Resistance R (Note 5) 370 MIN (GND to RW) End-to-End Resistance R 22 k TOTAL (GND to RW) R Tolerance T = +25C -20 +20 % TOTAL A Temp Coefficient T WR set to 40h 250 ppm/C CV RH, RW Capacitance C 10 pF POT 2 DS1841