Datasheet

ST7540 Electrical characteristics
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5V Voltage regulator
VDC
Linear regulator output
voltage
0 < Io < 50mA
7.5V < V
CC
< 13.5V
-5% 5.05 +5% V
3.3V Voltage regulator
V
DD
Linear regulator output
voltage
0 < Io < 50mA
7.5V < V
CC
< 13.5V
-5% 3.3 +5% V
Other functions
T
RSTO
Reset time
See Figure 23;
Xtal = 16MHz
50 ms
T
WD
Watch-dog pulse width See Figure 23 125 ns
T
WM
Watch-dog pulse
period
Minimum value.
See Figure 23
250 ns
Maximum value.
See Figure 23
1490 ms
T
WO
Watch-dog time out See Figure 23 1.5 s
T
OUT
TX time out
Control register bit 7
and bit 8
1
3
s
T
OFF
Time Out OFF time Figure 22 125 ms
T
OFFD
RxTx 0->1 vs. time out
delay
Figure 22 20 µs
T
CD
Carrier detection time
selectable by register
Control register
bit 9 and bit10
Figure 14
500
1
3
5
µs
ms
ms
ms
T
DCD
CD_PD Propagation
delay
Figure 14 300 500 µs
M
CLK
Master clock output
selectable by register
Control register
bit 15 and bit 16
See Tabl e 1 2
fclock
fclock/2
fclock/4
off
MHz
BAUD Baud rate
Control register
bit 3 and bit 4
See Tabl e 1 2
600
1200
2400
4800
Baud
Table 5. Electrical characteristics (continued)
( V
DD
= +5V, V
CC
=+9 V, V
SS
= S V
SS
= GND = 0V,-40°C ≤ T
A
≤ 85°C, T
J
< 125°C,
unless otherwise specified)
Symbol Parameter Test condition Min. Typ. Max. Unit