DS2120
6 of 10
PIN DESCRIPTION
PIN
TSSOP SSOP
NAME FUNCTION
1 1 VREF
Regulator Output Voltage. 1.25V reference in LVD
mode; must be decoupled with a 4.7µF cap.
2–5, 7–12,
18–21,
23–26
4–7, 11–16,
22–25,
29–32
RxP, RxN Signal Termination. Connect to SCSI bus signal lines.
6, 22 8–10, 26–28 HS_GND
Heat Sink Ground. Internally connected to the mounting
pad. Should be connected to ground.
13 17 ISO
Isolation. When pulled high, terminating resistors and
biasing current sources are isolated from the SCSI bus.
14 18 GND
Signal Ground
15 19 MSTR/SLV
Master/Slave. Mode select for the noncontrolling
terminator. When pulled high (MSTR), the DIFFSENS
driver is enabled.
16 20 DIFFSENSE
DIFFSENSE. Output to drive the SCSI bus DIFFSENS
line.
17 21 DIFF_CAP
DIFFSENSE Capacitor. Connect a 0.1µF capacitor for
DIFFSENSE filter. Input to detect the type of device
(differential or single-ended) on the SCSI bus.
27, 28 36 TPWR
Termination Power. Connect to the SCSI TERMPWR
line and decouple with 2.2µF capacitor.
— 34 LVD
Low-Voltage Differential. Output of DIFFSENSE
receiver; output high indicates LVD bus operation.
— 2, 3, 33, 35 NC No Connection. Do not connect pins.
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Termpower Voltage, LVD Mode V
TPWR(LVD)
2.7 5.5 V
Logic 0 V
IL
-0.3 +0.8 V 13
Logic 1 V
IH
2.0
V
TPWR
+
0.3
V 13
Operating Temperature V
AMB
0 70 °C
