UC5603 9-Line SCSI Active Terminator FEATURES DESCRIPTION • Complies with SCSI, SCSI-2 and SPI-2 Standards • 6pF Channel Capacitance during Disconnect The UC5603 provides 9 lines of active termination for a SCSI (Small Computers Systems Interface) parallel bus. The SCSI standard recommends active termination at both ends of the cable segment. • 100µA Supply Current in Disconnect Mode • Meets SCSI Hot Plugging • -400mA Sourcing Current for Termination • +400mA Sinking Current for Active Negation Drivers • Logic Command Disconnects all Termination Lines • Trimmed Termination Current to 3% • Trimmed Impedance to 3% • Negative Clamping on all Signal Lines • Current Limit and Thermal Shutdown Protection The UC5603 provides a disconnect feature which, when opened or driven high, will disconnect all terminating resistors, and disables the regulator; greatly reducing standby power. The output channels remain high impedance even without Termpwr applied. A low channel capacitance of 6pF allows units at interim points of the bus to have little to no effect on the signal integrity. Functionally the UC5603 is similar to its predecessor, the UC5601 - 18 line Active Terminator. Several electrical enhancements were incorporated in the UC5603, such as a sink/source regulator output stage to accommodate all signal lines at +5V, while the regulator remains at its nominal value, reduced channel capacitance to 6pF typical, and as with the UC5601, custom power packages are utilized to allow normal operation at full power conditions (1.2 watts). Internal circuit trimming is utilized, first to trim the impedance to a 3% tolerance, and then most importantly, to trim the output current to a 3% tolerance, as close to the max SCSI spec as possible, which maximizes noise margin in fast SCSI operation. Other features include negative clamping on all signal lines to protect external circuitry from latch-up, thermal shutdown and current limit. This device is offered in low thermal resistance versions of the industry standard 16 pin narrow body SOIC, 16 pin ZIP (zig-zag in line package) and 24 pin TSSOP. BLOCK DIAGRAM UDG-94049 3/97 Circuit Design Patented UC5603 ABSOLUTE MAXIMUM RATINGS Termpwr Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7V Signal Line Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0V to +7V Regulator Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65°C to +150°C Operating Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −55°C to +150°C Lead Temperature (Soldering, 10 Sec.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +300°C 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 CONNECTION DIAGRAMS DIL-16 (Top View) N or J Package TSSOP-24 (Top View) PWP Package * PWP package pin 5 serves as signal ground; pins 6, 7, 8, 9, 17, 18, 19, and 20 serve as heatsink/ground. ZIP-16 (Top View) Z Package SOIC-16 (Top View) DP Package * DP package pin 5 serves as signal ground; pins 4, 12, 13 serve as heatsink/ground. Note: Drawings are not to scale. 2 UC5603 ELECTRICAL CHARACTERISTICS Unless otherwise stated, these specifications apply for TA= 0°C to 70°C. TRMPWR = 4.75V DISCNCT = 0V. TA = TJ. PARAMETER Supply Current Section Termpwr Supply Current TEST CONDITIONS MIN All termination lines = Open All termination lines = 0.5V DISCNCT = Open Power Down Mode Output Section (Terminator Lines) Terminator Impedance ∆ILINE = -5mA to -15mA Output High Voltage VTRMPWR = 4V (Note 1) Max Output Current VLINE = 0.5V Max Output Current Output Clamp Level Output Leakage Output Capacitance Regulator Section Regulator Output Voltage Regulator Output Voltage Line Regulation Load Regulation Drop Out Voltage Short Circuit Current Sinking Current Capability Thermal Shutdown Thermal Shutdown Hysteresis Disconnect Section Disconnect Threshold Threshold Hysteresis 107 2.7 TJ = 25°C -21.1 0°C < TJ < 70°C -20.5 TJ = 25°C -20.3 VLINE = 0.5V, TRMPWR = 4V (Note 1) 0°C < TJ < 70°C -19.8 VLINE = 0.2V, TRMPWR = 4.0V to 5.25V 0°C < TJ < 70°C –22.0 ILINE = -30mA -0.2 TRMPWR = 0V to 5.25V VLINE = 0 to 4V REG = 0V VLINE = 5.25V DISCNCT = 4V TRMPWR = 0V to 5.25V, REG = Open VLINE = 0V to 5.25V DISCNCT = Open (Note 2) (DP Package) All Termination Lines = 5V TRMPWR = 4V to 6V IREG = +100mA to -100mA All Termination Lines = 0.5V VREG = 0V VREG = 3.5V 2.8 2.8 -200 200 1.3 100 Note 1: Measuring each termination line while other 8 are low (0.5V). Note 2: Guaranteed by design. Not 100% tested in production. 3 TYP MAX UNITS 12 200 100 18 220 150 mA mA µA 110 2.9 -21.9 -21.9 -21.9 -21.9 –24.0 -0.05 10 113 10 -22.4 -22.4 -22.4 -22.4 –25.4 0.1 400 100 400 Ohms V mA mA mA mA mA V nA µA nA 6 8 pF 2.9 2.9 10 20 0.7 -400 400 170 10 3 3 20 50 1 -600 600 V V mV mV V mA mA °C °C 1.5 160 1.7 250 V mV UC5603 APPLICATION INFORMATION UDG-94050 Figure 1: Typical Wide SCSI Bus Configurations Utilizing 1 UC5601 and 1 UC5603 Device UDG-94051 Figure 2: Typical Wide SCSI Bus Configurations Utilizing 3 UC5603 Devices. UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. 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