LT1794 Dual 500mA, 200MHz xDSL Line Driver Amplifier FEATURES DESCRIPTIO n Exceeds All Requirements For Full Rate, The LT 1794 is a 500mA minimum output current, dual op Downstream ADSL Line Drivers amp with outstanding distortion performance. The ampli- n 500mA Minimum I fiers are gain-of-ten stable, but can be easily compensated OUT n 11.1V Output Swing, V = 12V, R = 100W for lower gains. The extended output swing allows for S L n 10.9V Output Swing, V = 12V, I = 250mA lower supply rails to reduce system power. Supply current S L n Low Distortion: 82dBc at 1MHz, 2V Into 50W is set with an external resistor to optimize power dissipa- P-P n Power Saving Adjustable Supply Current tion. The LT1794 features balanced, high impedance in- n Power Enhanced Small Footprint Packages: puts with low input bias current and input offset voltage. 20-Lead TSSOP and 20-Lead SW Active termination is easily implemented for further sys- n 200MHz Gain Bandwidth tem power reduction. Short-circuit protection and thermal n 500V/m s Slew Rate shutdown insure the devices ruggedness. n Specified at 15V, 12V and 5V The outputs drive a 100W load to 11.1V with 12V U supplies, and 10.9V with a 250mA load. The LT1794, APPLICATIO S with its increased swing on lower supplies, can be used to n upgrade LT1795 line driver applications. High Density ADSL Central Office Line Drivers n High Efficiency ADSL, HDSL2, G.lite, The LT1794 is available in the very small, thermally SHDSL Line Drivers enhanced, 20-lead TSSOP for maximum port density in n Buffers line driver applications. The 20-lead SW is also available. n Test Equipment Amplifiers , LTC and LT are registered trademarks of Linear Technology Corporation. n Cable Drivers TYPICAL APPLICATIO High Efficiency 12V Supply ADSL Central Office Line Driver 12V R BIAS 24.9k +IN + SHDN 12.7 1/2 LT1794 1k 1:2* 110 100 1000pF 110 1k *COILCRAFT X8390-A OR EQUIVALENT I = 10mA PER AMPLIFIER SUPPLY 12.7 1/2 WITH R = 24.9k BIAS LT1794 SHDNREF IN + 1794 TA01 12V 1 U ULT1794 ABSOLUTE MAXIMUM RATINGS (Note 1) + Supply Voltage (V to V ) .................................... 18V Specified Temperature Range (Note 3) .. 40 C to 85 C Input Current ..................................................... 10mA Junction Temperature.......................................... 150 C Output Short-Circuit Duration (Note 2) ........... Indefinite Storage Temperature Range ................. 65 C to 150 C Operating Temperature Range ............... 40 C to 85 C Lead Temperature (Soldering, 10 sec).................. 300 C PACKAGE/ORDER INFORMATION ORDER PART ORDER PART TOP VIEW TOP VIEW NUMBER NUMBER V 1 20 V NC 1 20 NC NC 2 19 NC + + LT1794CFE LT1794CSW V 2 19 V IN 3 18 OUT LT1794IFE LT1794ISW OUT 3 18 OUT + +IN 4 17 V V 4 17 V SHDN 5 16 NC V 5 16 V SHDNREF 6 15 NC V 6 15 V + +IN 7 14 V V 7 14 V IN 8 13 OUT IN 8 13 IN NC 9 12 NC +IN 9 12 +IN V 10 11 V SHDN 10 11 SHDNREF FE PACKAGE SW PACKAGE 20-LEAD PLASTIC TSSOP 20-LEAD PLASTIC SO T = 150 C, q = 40 C/W, q = 3 C/W (Note 4) JMAX JA JC T = 150 C, q = 40 C/W, q = 3 C/W (Note 4) JMAX JA JC UNDERSIDE METAL CONNECTED TO V Consult factory for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full specified temperature range, otherwise specifications are at T = 25 C. A + V = 0V, pulse tested, 5V V 15V, V = 0V, R = 24.9k between V and SHDN unless otherwise noted. (Note 3) CM S SHDNREF BIAS SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Input Offset Voltage 15.0 mV OS l 7.5 mV Input Offset Voltage Matching 0.3 5.0 mV l 7.5 mV Input Offset Voltage Drift l 10 m V/ C I Input Offset Current 100 500 nA OS l 800 nA I Input Bias Current 0.1 4 m A B l 6 m A Input Bias Current Matching 100 500 nA l 800 nA e Input Noise Voltage Density f = 10kHz 8 nV/ Hz n i Input Noise Current Density f = 10kHz 0.8 pA/ Hz n + R Input Resistance V = (V 2V) to (V + 2V) l 550 MW IN CM Differential 6.5 MW 2 U W U U WWW