
ST72321xx-Auto Electrical characteristics
Doc ID 13829 Rev 1 189/243
19.3.2 Operating conditions with low voltage detector (LVD)
Subject to general operating conditions for V
DD
, f
CPU
, and T
A
.
19.3.3 Auxiliary voltage detector (AVD) thresholds
Subject to general operating conditions for V
DD
, f
CPU
, and T
A
.
Table 108. Operating conditions with low voltage detector (LVD)
Symbol Parameter Conditions Min Typ Max Unit
V
IT+(LVD)
Reset release threshold
(V
DD
rise)
VD level = High in option byte 4.0
(1)
4.2 4.5
V
VD level = Med. in option byte
(2)
3.55
(1)
3.75 4.0
(1)
VD level = Low in option byte
(2)
2.95
(1)
3.15 3.35
(1)
V
IT-(LVD)
Reset generation threshold
(V
DD
fall)
VD level = High in option byte 3.8 4.0 4.25
(1)
VD level = Med. in option byte
(2)
3.35
(1)
3.55 3.75
(1)
VD level = Low in option byte
(2)
2.8
(1)
3.0 3.15
(1)
V
hys(LVD)
LVD voltage threshold
hysteresis
V
IT+(LVD)
-V
IT-(LVD)
200 mV
Vt
POR
V
DD
rise time
(2)(3)
LVD enabled 6µs/V 100ms/V -
t
g(VDD)
V
DD
glitches filtered (not
detected) by LVD
(4)
40 ns
1. Data based on characterization results, tested in production for ROM devices only
2. Data based on characterization results, not tested in production
3. When Vt
POR
is faster than 100µs/V, the Reset signal is released after a delay of maximum 42µs after V
DD
crosses the
V
IT+(LVD)
threshold.
4. If the medium or low thresholds are selected, the detection may occur outside the specified operating voltage range. Below
3.8V, device operation is not guaranteed.
Table 109. Auxiliary voltage detector (AVD) thresholds
Symbol Parameter Conditions Min Typ Max Unit
V
IT+(AVD)
10 AVDF flag toggle threshold
(V
DD
rise)
VD level = High in option byte 4.4
(1)
4.6 4.9
(1)
V
VD level = Med. in option byte 3.95
(1)
4.15 4.4
(1)
VD level = Low in option byte 3.4
(1)
3.6 3.8
(1)
V
IT-(AVD)
01 AVDF flag toggle threshold
(V
DD
fall)
VD level = High in option byte 4.2
(1)
4.4 4.65
(1)
VD level = Med. in option byte 3.75
(1)
4.0 4.2
(1)
VD level = Low in option byte 3.2
(1)
3.4 3.6
(1)
V
hys(AVD)
AVD voltage threshold hysteresis V
IT+(AVD)
-V
IT-(AVD)
200
mV
V
IT-
Voltage drop between AVD flag set
and LVD reset activated
V
IT-(AVD)
-V
IT-(LVD)
450
1. Data based on characterization results, tested in production for ROM devices only
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