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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
0.2 - 1 µs
t
W(RESET_N)
pulse width on pin RESET_N 0.2 - - µs
Crystal oscillator
f
clk
clock frequency crystal
[1][2]
- 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
°
Cto+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
see Figure 9
--15ms
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
[1]
V
CC
= 3.0 V to 3.6 V; T
amb
=
−
40
°
Cto+70
°
C; unless otherwise specified.
Symbol Parameter Conditions Min Typ Max Unit
t
t(HL)
,
t
t(LH)
output transition time 4 - 15 ns