LTC1427-50 Micropower, 10-Bit Current Output DAC with SMBus Serial Interface FEATURES DESCRIPTION n Precision 50A, 1.5% Initial Full-Scale Output The LTC 1427-50 is a micropower, 10-Bit current output Current, 2.5% Over Temperature DAC with an output range of 0A to 50A. The DAC output is n Wide Output Voltage DC Compliance: 15V to guaranteed monotonic and DNL is less than 0.9LSB under all (V 1.3V) operating conditions. Full-scale accuracy is 2.5% over CC n Wide Supply Range: 2.7V V 5.5V the commercial temperature range. The LTC1427-50 oper- CC n Supply Current in Shutdown: 10A Typ ates with power supply voltages from 2.7V to 5.5V and the n Low Supply Current: 115A Typ DAC current source output can be biased from (V 1.3V) CC n Available in 8-Pin SO to 15V. n SMBus Serial Interface The LTC1427-50 communicates with external circuitry by n Four Selectable SMBus Addresses using the SMBus serial interface. It acts as an SMBus slave n DAC Powers Up at Zero or Midscale device using one of four selectable SMBus addresses set by n DAC Contents Are Retained in Shutdown the two address pins AD0 and AD1 . U On power-up, the DAC output assumes midrange or zero APPLICATIONS scale, depending on the logic state of the two address pins. n The LTC1427-50 can be shut down through the SHDN pin or LCD Contrast and Backlight Brightness Control n by setting the SHDN bit = 1 in the SMBus command byte. Power Supply Voltage Adjustment n Digital data for the DAC output is retained internally and the Battery Charger Voltage/Current Adjustment n supply current drops to 10A typically when in shutdown. GaAs FET Bias Adjustment n Trimmer Pot Elimination The LTC1427-50 is available in an 8-pin SO package. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATION Digitally Controlled LCD Bias Generator D1 L1 V * OUT 6 5 R1 V CC 226k V SW IN 3.3V 1% LT1317 3 2 2 TO 4 SHDN FB SHDN CELLS C1 R2 V 1F GND C LTC1427-50 1F 12.1k 1 8 4 1 1% SHDN V CC PU 2 7 4700pF (e.g., 8051) AD1 I OUT 3 6 100k AD0 SCL P1.2 4 5 GND SDA P1.1 P1.0 1427 TA02 L1 = 10 H SUMIDA CD43 MURATA-ERIE LQH3C *V = 12.7V TO 24V IN 11mV STEPS OUT OR COILCRAFT DO1608 15mA (2 CELLS) D1 = MBR0530 35mA ( 3 CELLS) 1 U ULTC1427-50 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) ORDER PART TOP VIEW Total Supply Voltage (V ) ........................................ 7V CC NUMBER SHDN 1 8 V CC Input Voltage (All Inputs)............. 0.3V to (V + 0.3V) CC AD1 2 7 I OUT DAC Output Voltage ...................... 15V to (V + 0.3V) LTC1427CS8-50 CC AD0 3 6 SCL DAC Output Short-Circuit Duration .................. Indefinite GND 4 5 SDA Operating Ambient Temperature Range ....... 0C to 70C S8 PART MARKING S8 PACKAGE Junction Temperature.......................................... 125C 8-LEAD PLASTIC SO Storage Temperature Range ................. 65C to 150C 14275 T = 125C, = 190C/ W JMAX JA Lead Temperature (Soldering, 10 sec.)................. 300C Consult factory for Industrial and Military grade parts. T = operating temperature range unless otherwise specified. ELECTRICAL CHARACTERISTICS A SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Supply Voltage l 2.7 5.5 V CC I Supply Current V = V = V = V = 3.3V l 115 225 A CC SHDN SCL SDA CC V = 0V l 10 25 A SHDN DAC Resolution l 10 Bits I DAC Full-Scale Current V = 3.3V, V(I ) = 0V 49.25 50 50.75 A FS CC OUT l 48.75 50 51.25 A I DAC Zero-Scale Current V = 3.3V, V(I ) = 0V l 0.1 200 nA ZS CC OUT DNL DAC Differential Nonlinearity V = 3.3V, Monotonicity Guaranteed, V(I ) = 0V l 0.15 0.9 LSB CC OUT Supply Voltage Rejection V = 2.7V to 5.5V, V(I ) = 0V l 8 LSB CC OUT Output Voltage Rejection V = 3.3V, Full-Scale Current, 15V V(I ) 2V l 5 LSB CC OUT I Logic Input Current 0V V V l 1 A IN IN CC V High Level Input Voltage AD0, AD1 l V 0.3 V IH CC SHDN l 2.4 V SCL, SDA l 1.4 V V Low Level Input Voltage SHDN, AD0, AD1 l 0.8 V IL SCL, SDA l 0.6 V V Low Level Output Voltage I = 3mA, SDA Only l 0.4 V OL OUT 2 U W U W U WW