Philips Semiconductors ISP1122
USB stand-alone hub
Product specification Rev. 03 — 29 March 2000 5 of 48
9397 750 07002 © Philips Electronics N.V. 2000. All rights reserved.
[1] Symbol names with an overscore (e.g.NAME) indicate active LOW signals.
[2] The voltage at pin Vreg(3.3) is gated by theRESET pin. This allows fully self-powered operation by
connecting RESET to VBUS (+5 V USB supply). If VBUS is lost upstream port D+ will not be driven.
[3] SeeTable 4 “Mode selection”.
[4] Todisable a downstreampor t connect both D+and D−to VCC via a 1 MΩresistor; unused ports must
be disabled in reverse order starting from port 5.
[5] Analog detection circuit can be switched off using an external EEPROM, seeTab le 23 ; in this case,
the pin functions as a logic input (TTL level).
[6] Downstream ports 1 and 2 cannot be disabled.
DP1 27 AI/O downstream port 1 D+ connection (analog) [6]
DM0 28 AI/O upstream port D− connection (analog)
DP0 29 AI/O upstream port D+ connection (analog)
DM2 30 AI/O downstream port 2 D− connection (analog) [6]
DP2 31 AI/O downstream port 2 D+ connection (analog) [6]
PSW1/GL1[3] 32 O modes 4 to 6: power switch control output for downstream
port 1 (open-drain, 6 mA)
modes 0 to 3, 7: GoodLink LED indicator output for
downstream port 1 (open-drain, 6 mA); to connect an LED
use a 330 Ω series resistor
Table 2: Pin description for SO32 and SDIP32
…continued
Symbol[1] Pin Type Description