AN8612NSR SCSI Active Terminator IC ■ Overview (100µA in stand-by condition) • Small output terminal capacitance : 4.5 pF, typ. • High accuracy regulator : 2.85V±60mV 1.45 0.5 8.4±0.3 11.73±0.3 Number in ( ) is a reference value. 24-pin SOP Package (HSOP024-P-0450) ■ Application SCSI interface board of PC SCSI equipment such as CD-ROM, MO, PD and MD printer ■ Block Diagram + VCC 1 + – 12 0.1µF 1µF 18 13 17 16 Thermal Shut Down 15 14 11 10 Band Gap Reference 9 8 7 5 4 3 2 23 22 STANDBY 21 24 20 6 19 SG SG SG SG SG SG SG SG SG SG SG SG SG SG SG SG SG SG LINE 1 LINE 2 LINE 3 LINE 4 LINE 5 LINE 6 LINE 7 LINE 8 LINE 9 LINE 10 LINE 11 LINE 12 LINE 13 LINE 14 LINE 15 LINE 16 LINE 17 LINE 18 16.0±0.3 1.27 (0.2) 3.15±0.2 (7.8) (0075) (9.2) 24 23 22 21 20 19 18 17 16 15 14 13 1.45 • Active termination of 18 signal lines • Low consumption power owing to stand-by function built-in 1 2 3 4 5 6 7 8 9 10 11 12 0.1±0.1 ■ Features (6.0) (4.6) 0.4±0.25 Unit : mm The AN8612NSR is a terminator IC complying with the standard interface standards [SCSI-I/II] for personal computer, work station and various information equipment. Fixed resistor and regulator which are separately provided in conventional ICs are incorporated in single chip for the AN8612NSR. The stand-by function is also built in the AN8612NSR. Moreover, this IC can easily satisfy the maximum terminal capacitance of 25 pF of the SCSI-II standard, because of its small output terminal capacitance. It can support the 10 M byte/s of SCSI-II and 20 M bytes/s of Fast-20. ■ Absolute Maximum Rating (Ta=25˚C) Symbol Rating Supply voltage Parameter VCC – 0.3 to + 7.0 Unit Supply current ICC 500 mA mW V Power dissipation Note) PD 2250 Operating ambient temperature Topr –20 to + 60 ˚C Storage temperature Tstg –55 to + 150 ˚C Note) Ta=60˚C and printed board (80.0 × 80.0 × 1.2mm) ■ Recommended Operation Range (Ta=25˚C) Parameter Operating supply voltage Symbol Range VCC 4.0V to 5.5V ■ Electrical Characteristics (VCC=5.0V, Ta=25±2˚C) Parameter Symbol Condition ICC3 STANDBY= “L” All SGLINE=open STANDBY= “L” All SGLINE=0.2V STANDBY=open STANDBY terminal “L” input current ISTBYL VCC=5.5V, VI=0V STANDBY terminal “L” input current STANDBY terminal positive direction Threshold voltage STANDBY terminal negative direction Threshold voltage ISTBYH VCC=5.5V, VI=5.5V Maximum output current SGLINE1-18 ISG Supply current 1 ICC1 Supply current 2 ICC2 Supply current 3 Output leak current 1 SGLINE1 to 18 Output leak current 2 SGLINE1 to 18 –150 typ max Unit 44 54 mA 458 530 mA 100 200 µA µA –50 1 µA VTH+ 1.3 1.5 1.7 V VTH– 1.1 1.3 1.5 V VSG=0.2V VCC=5.5V STANDBY=open, VSG=0V VCC=5.5V STANDBY=open, VSG=2.85V VCC=4.0 to 5.5V All SGLINE=open VCC=3.2V All SGLINE=open 19.8 23.0 26.2 mA RSG ISG=5mA to 15mA 107 115 123 Ω VSGH VCC=4.0 to 5.5V All SGLINE=open 2.78 2.85 2.92 V ILK1 ILK2 REG · output voltage VREG1 REG · output voltage VREG2 Termination resistance value SGLINE1 to 18 “H” level output voltage SGLINE1 to 18 STANDBY terminal hysteresis width min µA –1 –1 2.79 2.85 µA 2.91 V 2.00 V VHYS (200) Output terminal capacitance CSG (4.5) Thermal shut-down temperature TTSD (170) Note) Number in ( ) is a design reference value but not guaranteed one. 1 mV 8 pF ˚C ■ Package Power Dissipation PD –Ta 3200 Power Dissipation PD (mW) 2800 Evaluation PCB (80.0 × 80.0 × 1.2mm) Tjmax=150˚C PD=3100mW (25˚C) 2400 2000 1600 1200 800 400 0 0 25 50 75 100 125 150 Ambient Temperature Ta (˚C) ■ Pin Name Pin No. Pin name Pin No. Pin name REGOUT 13 VCC (TERMPWR) Note 2) 2 SGLINE14 14 SGLINE5 3 SGLINE13 15 SGLINE4 4 SGLINE12 16 SGLINE3 5 SGLINE11 17 SGLINE2 6 GND Note 1) 18 SGLINE1 7 SGLINE10 19 GND Note 4) 8 SGLINE9 20 SGLINE18 9 SGLINE8 21 SGLINE17 10 SGLINE7 22 SGLINE16 11 SGLINE6 23 SGLINE15 24 STANDBY Note 3) 1 12 VCC (TERMPWR) Note 2) Note 1) On PCB, the same wide pattern as Pin6 GND terminal and Pin19GND terminal (One layer one surface GND of multi-layer board is recommended for PCB.) Note 2) VCC should be connected with SCSI termination resistive power supply TERMPWR. Note 3) STANDBY terminal input voltage : VI < VTH– for active mode and VI >VTH+ for stand-by mode Opening the STANDBY terminal also brings the stand-by mode. ■ Pin Descriptions Equivalent circuit Pin name Pin No. VCC 100kΩ 24 24 STANDBY GND VCC 115Ω SGLINE 1 — 2, 3 4, 5 7, 8 9, 10 11, 14 15, 16 17, 18 20, 21 22, 23 REGOUT 2 SGLINE 18 STANDBY GND 12 13 12, 13 VCC GND VCC 1 1 REGOUT STANDBY GND 20 kΩ ■ Precautions on Input Capacitance The Interface Terminal Input Capacitance MAX25pF Standard are added from the SCSI II. This is because large stamp input capacitance may prevent the normal signal transmission. The capacitance value which does not cause the transmission error differs, depending on the connection conditions of SCSI equipment (such as distance between equipment, number of equipment units and cable impedance), so, its proper value for the AN8612NSR can not be identified. However, when the input capacitance value specified in SCSII Standard, MAX25pF is used, transmission error due to input capacitance can hardly occur. The input capacitance value is determined by the sum of the following capacitances : active terminator (ex. 4.5 pF), printed board (ex. 10 pF), driver receiver incorporated SCSI controller (ex. 10 pF) and connector (ex. 0.5 pF). [Evaluation Printed Board] Therefore, particular care should be taken to each device for input capacitance. For example, on the evaluation printed board of the AN8612NSR, the measured capacitance value per signal line is approx. 2.2 pF and that per unit area is 0.13 pF/mm 2. The thickness of printed board is 1 mm and the dielectric constant of glass epoxy is 3.8 to 5. For printed board, since the capacitance value differs, depending on the thickness between layers and wiring length, it should be measured actually. Also, it should be measured by using the capacitance meter which can measure the capacitance value of semiconductor. Front Back ■ Application Circuit SCSI equipment (PC interface board) SGLINE1 SGLINE18 SCSI equipment (MO) SGLINE1 AN8612NSR VCC REGOUT STANBAY SGLINE18 SGLINE1 AN8612NSR VCC REGOUT STANBAY GND SCSI equipment (CD-ROM) SGLINE18 AN8612NSR VCC REGOUT STANBAY GND GND