Philips ISP1521 ユーザーズマニュアル
Philips Semiconductors
ISP1521
Hi-Speed USB hub controller
Product data
Rev. 03 — 24 November 2004
38 of 53
9397 750 13702
© Koninklijke Philips Electronics N.V. 2004. All rights reserved.
16. Dynamic characteristics
[1]
Recommended accuracy of the clock frequency is 500 ppm for the crystal.
[2]
Suggested values for external capacitors when using a crystal are 22 pF to 27 pF.
[1]
All pins are 5 V tolerant.
Table 40:
Dynamic characteristics: system clock timing
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Reset
t
W(POR)
internal power-on reset pulse
width
width
0.2
-
1
µ
s
t
W(RESET_N)
pulse width on pin RESET_N
0.2
-
-
µ
s
Crystal oscillator
f
clk
clock frequency
crystal
-
12
-
MHz
External clock input
δ
clock duty cycle
-
50
-
%
Table 41:
Dynamic characteristics: overcurrent sense timing
V
CC
= 3.0 V to 3.6 V; T
amb
=
−
40
°
C to +70
°
C; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
Overcurrent sense pins OC1_N to OC7_N
t
trip
overcurrent trip response time from
OCn_N LOW to PSWn_N HIGH
OCn_N LOW to PSWn_N HIGH
see
-
-
15
ms
Overcurrent input: pins OCn_N; power switch output: pins PSWn_N.
Fig 9.
Overcurrent trip response timing.
mbl032
V
CC
0 V
overcurrent
input
V
CC
0 V
power switch
output
t
trip
∆
V
trip
Table 42:
Dynamic characteristics: digital pins
V
CC
= 3.0 V to 3.6 V; T
amb
=
−
40
°
C to +70
°
C; unless otherwise specified.
Symbol
Parameter
Conditions
Min
Typ
Max
Unit
t
t(HL)
,
t
t(LH)
output transition time
4
-
15
ns