UC5607 Plug and Play, 18-Line SCSI Active Terminator FEATURES DESCRIPTION • Complies with SCSI and SCSI-2 Standards The UC5607 provides 18 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 segment. • 8pF Channel Capacitance during Disconnect • SCSI Plug and Play, Dual Low Disconnect, Logic Low Command Disconnects All Termination Lines • Meets SCSI Hot Plugging Capability • -650mA Sourcing Current for Termination The UC5607 provides a low disconnect feature which will disconnect all terminating resistors, and will disable the regulator, greatly reducing standby power. The output channels remain high impedance even without Termpwr applied. The UC5607 terminator is specially designed with two disconnect pins for full SCSI Plug and Play (PnP) applications. Custom power packages are utilized to allow normal operation at full power conditions (2 Watts). • +200mA Sinking Current for Active Negation • 200µA Supply Current in Disconnect Mode Internal circuit trimming is utilized, first to trim the impedance to a 7% tolerance, and then most importantly, to trim the output current to a 7% tolerance, as close to the max SCSI spec as possible, which maximizes noise margin in fast SCSI operation. • Trimmed Termination Current to 7% Other features include thermal shutdown and current limit. • Trimmed Impedance to 7% This device is offered in low thermal resistance versions of the industry standard 28 pin wide body SOIC, and 28 pin PLCC, as well as 24 pin DIP. • Provides Active Termination for 18 Lines BLOCK DIAGRAM Circuit Design Patented 7/98 DISCNCT1 DISCNCT2 Connect Connect Connect 1 0 1 0 1 1 Disc 0 0 UDG-94124 UC5607 CONNECTION DIAGRAMS ABSOLUTE MAXIMUM RATINGS Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A Storage Temperature . . . . . . . . . . . . . . . . . . . -65°C to +150°C Operating Temperature . . . . . . . . . . . . . . . . . -55°C to +150°C Lead Temperature (Soldering, 10 Sec.). . . . . . . . . . . . . +300°C PLCC-28 (Top View) QP Package Unless otherwise specified all voltages are with respect to Ground. Currents are positive into, negative out of the specified terminal. Consult Packaging Section of Unitrode Integrated Circuits databook for thermal limitations and considerations of packages. RECOMMENDED OPERATING CONDITIONS Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . 3.8V to 5.25V Signal Line Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +5V Disconnect Input Voltage . . . . . . . . . . . . . . . . . . 0V to Termpwr * QP package pins 12 - 18 serve as both heatsink and signal ground. SOIC-28 (Top View) DWP Package ** DISCNCT2 is internally tied to ground. DIL-24 (Top View) N or J Package * DWP package pin 8 serves as signal ground; pins 7, 8, 9, 20, 21, 22 serve as heatsink/ground. Note: Drawings are not to scale. 2 UC5607 ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA = 0°C to 70°C. TRMPWR = 4.75V, DISCNCT1 = DISCNCT2 = 2.2V. TA = TJ. PARAMETER TEST CONDITIONS MIN TYP MAX Supply Current Section Termpwr Supply Current All termination lines = Open All termination lines = 0.5V DISCNCT1 = DISCNCT2 = 0V Power Down Mode Output Section (Terminator Lines) Terminator Impedance DILINE = –5mA to –15mA Output High Voltage Max Output Current Max Output Current Output Leakage Output Capacitance Regulator Section Regulator Output Voltage UNIT S 30 420 300 45 470 500 mA mA mA TJ = 25°C 0°C < TJ < 70°C VTRMPWR = 4V (Note 1) TJ = 25°C 0°C < TJ < 70°C VLINE = 0.5V TJ = 25°C 0°C < TJ < 70°C TJ = 25°C VLINE = 0.5V, TRMPWR = 4V (Note 1) 0°C < TJ < 70°C DISCNCT1 = DISCNCT2 = 0V, TRMPWR = 0V to 5.25V DISCNCT1 = DISCNCT2 = 0V (Note 2) 102 97 2.6 2.55 –19.5 –18.5 –18.0 –17.0 110 110 2.9 2.9 –21.9 –21.9 –21.9 –21.9 10 8 118 129 3.1 3.2 –22.4 –22.4 –22.4 –22.4 400 10 Ohms Ohms V V mA mA mA mA nA pF All Termination Lines = 5V 2.7 2.55 2.9 2.9 10 20 3.1 3.2 20 50 V V mV mV TJ = 25°C 0°C < TJ < 70°C Line Regulation TRMPWR = 4V to 6V Load Regulation IREG = +100mA to –100mA Note 1: Measuring each termination line while other 17 are low (0.5V). Note 2: Guaranteed by design. Not 100% tested in production. APPLICATION INFORMATION UDG-98136 Figure 1: Typical SCSI Bus Configuration Utilizing UC5607 Device UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 FAX (603) 424-3460 3 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. TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. 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