Texas Instruments THUNDER TNETX3270 User Manual
Page 63
TNETX3270
ThunderSWITCH
24/3 ETHERNET
SWITCH
WITH 24 10-MBIT/S PORTS AND 3 10-/100-MBIT/S PORTS
SPWS043B – NOVEMBER 1997 – REVISED APRIL 1999
63
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
power-up OSCIN and RESET
timing requirements (see Figure 23)
NO.
MIN
NOM
MAX
UNIT
Frequency drift, OSCIN clock
±
50
ppm
1
tc(OSCIN)
Cycle time, OSCIN
12
ns
2
tw(OSCINL)
Pulse duration, OSCIN low
4.8
7.2
ns
3
tw(OSCINH)
Pulse duration, OSCIN high
4.8
7.2
ns
4
tw(RESET)
Pulse duration, RESET low
200
µ
s
5
tsu(RESET)
Setup time, RESET low before OSCIN
↑
7
ns
6
th(RESET)
Hold time, RESET low after OSCIN
↑
3
ns
7
td(OSCIN)
Delay time, from OSCIN invalid to OSCIN valid (stable)
25
ms
8
td(RESET)
Delay time, from OSCIN stable to RESET
↑
25
ms
9
tt(OSCIN)
Transition time, OSCIN rise and fall
2
ns
RESET must be held low at least 25 ms after both power supplies are stable and OSCIN has reached its stable
operating frequency. RESET can be set to 0 for a minimum of 200
µ
s to reset the device.
ППП
ППП
ООО
ООО
OSCIN
(input)
RESET
(input)
ППП
ППП
ППП
VDD(2.5V)
(input)
VDD(3.3V)
(input)
7
5
9
9
1
6
4
8
3
2
Figure 23. Power-Up OSCIN and RESET