Philips Universal Serial Bus ISP1122 - Manual (Page 38)

Philips Semiconductors
ISP1122
USB stand-alone hub
Product specification Rev. 03 — 29 March 2000 38 of 48
9397 750 07002 © Philips Electronics N.V. 2000. All rights reserved.
16. Test information
The dynamic characteristics of the analog I/O ports (D
+
and D
−)
as listed in Table 32
and Table 33 , were determined using the circuit shown in Figure 22 .
Fig 21. I 2 C-bus timing.
handbook, full pagewidth
P S S P
MGR779
tHD;STA
tBUF tHD;STA
tSU;STA tSU;DAT
tf
tHIGH tSU;STO
tr
tHD;STA
tLOW
SDA
SCL
Load capacitance:
C
L
= 50 pF (full-speed mode)
C
L
= 200 pF or 600 pF (low-speed mode, minimum or maximum timing).
Speed selection:
full-speed mode (FS): 1.5 k
Ω
pull-up resistor on D
+
low-speed mode (LS): 1.5 k
Ω
pull-up resistor on D
−
.
Fig 22. Load impedance for D+ and D- pins.
MGR775
handbook, halfpage
S1
S1
test point
test
closed
closed
open
open
D
−
/LS
D
+
/LS
D
−
/FS
D
+
/FS
CL
Vreg(3.3)
15 k Ω
RPU
1.5 k
Ω
20 Ω
D.U.T.