Datasheet

ST8024 Electrical characteristics
15/31
V
DD
= 3.3 V, V
DDP
= 5 V, f
XTAL
= 10 MHz, unless otherwise noted. Typical values are to
T
A
= 25 °C.
Note: 1 All parameters remain within limits but are tested only statistically for the temperature
range. When a parameter is specified as a function of V
DD
or V
CC
it means their actual value
at the moment of measurement.
2 To meet these specifications, pin V
CC
should be decoupled to CGND using two ceramic
multilayer capacitors of low ESR both with values of 100 nF and 100 nF (see Figure 10).
3 Permitted capacitor values are 100 + 100 nF, or 220 nF.
4 Transition time and duty factor definitions are shown in Figure 3; δ = t
1
/(t
1
+ t
2
).
5 Pin CMDVCC
is active LOW; pin RSTIN is active HIGH; for CLKDIV1 and CLKDIV2
functions see Ta bl e 2 0
6 Pin PRES
is active LOW; pin PRES is active HIGH see Figure 8 and Figure 9; PRES has an
integrated 1.25 µA current source to GND. (PRES to V
DD
); the card is considered present if
at least one of the inputs PRES
or PRES is active.
Figure 3. Definition of output and input transition times
Table 20. Timing
Symbol Parameter Test conditions Min. Typ. Max. Unit
t
ACT
Activation time (See Figure 5) 180 220 µs
t
DE
Deactivation time (See Figure 7) 60 80 100 µs
t
3
Start of the windows for sending
CLK to card
(See Figure 6) 130 µs
t
5
End of the windows for sending
CLK to card
(See Figure 6) 140 µs
t
debounce
Debounce time pins PRES and
PRES
(See Figure 8) 140 µs