UCC5619 27-Line SCSI Terminator With Reverse Disconnect FEATURES DESCRIPTION • Complies with SCSI, SCSI-2, SCSI-3, SPI and FAST-20 (Ultra) Standards UCC5619 provides 27 lines of active termination for a SCSI (Small Computer Systems Interface) parallel bus. The SCSI standard recommends active termination at both ends of the cable. • 2.5pF Channel Capacitance during Disconnect • 100µA Supply Current in Disconnect Mode • 4V To 7V Operation • 110 Termination • Completely Meets SCSI Hot Plugging • –900mA Sourcing Current for Termination • +500mA Sinking Current for Active Negation • Logic Command Disconnects all Termination Lines • Trimmed Impedance to 5% • Current Limit and Thermal Shutdown Protection BLOCK DIAGRAM Circuit Design Patented 10/98 The UCC5619 is ideal for high performance 5V SCSI systems. During disconnect the supply current is typically only 100µA, which makes the IC attractive for lower powered systems. The UCC5619 is designed with a low channel capacitance of 2.5pF, which eliminates effects on signal integrity from disconnected terminators at interim points on the bus. The power amplifier output stage allows the UCC5619 to source full termination current and sink active negation current when all termination lines are actively negated. The UCC5619, as with all Unitrode terminators, is completely hot pluggable and appears as high impedance at the teminating channels with VTRMPWR = 0V or open. Internal circuit trimming is utilized, first to trim the 110Ω impedance, and then most importantly, to trim the output current as close to the maximum SCSI-3 specification as possible, which maximizes noise margin in fast SCSI operation. Other features include thermal shutdown and current limit. This device is offered in low thermal resistance versions of the industry standard 36 pin wide body QSSOP (MWP) and 48 pin LQFP (FQP). Consult SSOP-36 (MWP QSSOP-36) and FQP-48 Packaging Diagram for exact dimensions. UDG-96108 UCC5619 CONNECTION DIAGRAM ABSOLUTE MAXIMUM RATINGS TRMPWR Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5A Storage Temperature . . . . . . . . . . . . . . . . . . . −65°C to +150°C Junction Temperature . . . . . . . . . . . . . . . . . . . −55°C to +150°C Lead Temperature (Soldering, 10 Sec.). . . . . . . . . . . . . +300°C LFQP-48 (Top View) FQP Package HS/GND LINE 8 LINE 7 LINE 6 LINE 5 LINE 22 HS/GND HS/GND LINE 9 LINE 23 Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Databook for thermal limitations and considerations of packages. LINE 24 N/C 48 47 QSSOP-36 (Top View) MWP Package 46 38 40 39 1 37 36 LINE 21 LINE 25 2 35 LINE 20 LINE 26 3 34 LINE 19 LINE 27 4 33 REG 45 44 43 42 N/C 41 LINE8 1 36 LINE7 HS/GND 5 32 HS/GND LINE9 2 35 LINE6 HS/GND 6 31 HS/GND HS/GND 7 30 HS/GND HS/GND 8 29 HS/GND N/C 9 28 TRMPWR LINE23 LINE24 3 4 34 33 LINE5 LINE22 LINE25 5 32 LINE21 DISCNCT1 10 27 LINE 18 LINE26 6 31 LINE20 LINE 10 11 26 LINE 17 LINE27 7 30 LINE19 LINE 11 12 13 14 25 LINE 16 GND* 8 29 REG GND* 9 28 GND* N/C LINE 12 LINE 15 LINE 4 GND* 10 27 GND* 11 26 GND* LINE10 12 25 TRMPWR LINE 13 LINE 14 HS/GND HS/GND LINE 3 LINE 2 DISCNCT LINE11 13 24 LINE18 LINE12 14 23 LINE17 LINE13 15 22 LINE16 LINE14 16 21 LINE15 LINE1 17 20 LINE4 LINE2 18 19 LINE3 15 16 17 18 19 20 21 22 23 24 LINE 1 HS/GND * MWP package pins 8 - 10 and 26 - 28 serve as heatsink/ ground. ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C, TRMPWR = 4.75V, DISCNCT = 4.75V, TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Supply Current Section TRMPWR Supply Current Power Down Mode All Termination Lines = Open 1 2 mA All Termination Lines = 0.2V 630 650 mA DISCNCT = 0V 100 200 µA Output Section (Termination Lines) Termination Impedance (Note 3) 104.5 110 115.5 Ω Output High Voltage (Note 1) 2.6 2.8 3.0 V VLINE = 0.2V, TJ = 25°C −22.1 −23.3 −24 mA VLINE = 0.2V −20.7 −23.3 −24 mA VLINE = 0.2V, TRMPWR = 4V, TJ = 25°C (Note 1) −21 −23 −24 mA VLINE = 0.2V, TRMPWR = 4V (Note 1) −20 −23 −24 mA Max Output Current 2 UCC5619 ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C, TRMPWR = 4.75V, DISCNCT = 4.75V, TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Output Section (CONT.) 22.4 mA Output Leakage VLINE = 0.5V DISCNCT = 0V, TRMPWR = 0V to 5.25V 10 400 nA Output Capacitance DISCNCT = 0V (Note 2) 2.5 4 pF 2.8 3.0 V 0.4 0.8 V Regulator Section Regulator Output Voltage 2.6 Drop Out Voltage All Termination Lines = 0.2V Short Circuit Current VREG = 0V −650 −900 –1300 mA Sinking Current Capability VREG = 3.5V 300 500 900 mA Thermal Shutdown 170 °C Thermal Shutdown Hysteresis 10 °C Disconnect Section Disconnect Threshold 0.8 DISCNCT = 0V Input Current 1.5 2.0 V –20 –60 µA PIN DESCRIPTIONS DISCNCT: Taking this pin low causes all channels to become high impedance, and the chip to go into low-power mode; a high state or leaving it open allows the channels to provide normal termination. LINE1 - LINE27: 110Ω termination channels. REG: Output of the internal 2.7V regulator; bypass with a 4.7 F capacitor to GND. TRMPWR: Power for the IC; bypass with a 4.7 F capacitor to GND. GND: Ground reference for the IC. UCC5619 11 DISCNCT TERMPWR 25 REG 29 TERMPWR 4.7µF LINE1 LINE27 17 7 DATA BYTES 1 AND 2 +2 PARITY BITS 4.7µF CONTROL BYTES TO DRIVERS AND RECEIVERS TO SCSI BUS Figure 1. Typical wide SCSI bus configuration using the UCC5619 UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 FAX (603) 424-3460 3 UDG-98072 IMPORTANT NOTICE Texas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue any product or service without notice, and advise customers to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. 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