psb21391 Infineon Technologies Corporation, psb21391 Datasheet - Page 171

• Manufacturer Part Number: psb21391
• Description: Siemens Codec With Upn Transceiver
• Manufacturer: Infineon Technologies Corporation

6.2
The integrated undervoltage detection circuit can be enabled or disabled by pinstrapping
the VDDDET pin to’V
voltage (5V or 3.3 V) and sets RSTO to ’low’ if the supply voltage falls below the
detection level V
detection level plus hysteresis (V
t
V
listed in table 24.
.
Table 24
Levels of the Undervoltage Detection
Parameter
V
Hysteresis
Above the minimum operating voltage of the undervoltage detection (1.5V) the reset
output RSTO is in a defined state and acts as a power-on reset for the system.
If the supply voltage falls below V
= ’low’) and all registers are reset by the internal reset. The MCLK is stopped
immediately which may result in a shorter high period of the clock signal.
If the supply voltage exceeds V
output with its default frequency. The external reset pulse is extended by 64 ms due to
the oscillator start until a stable clock is achieved.
The maximum delay for the activation of the undervoltage detection t
maximum rising/falling edge of the supply voltage for activation/deactivation of the
undervoltage detection is 0.1V/µs.
Figure 81 shows the undervoltage control timing.
Data Sheet
DEACT
DD
DET
= 3.3V (Pin VDDSEL = ’V
expires (64 ms). The specified detection level V
Undervoltage Detection (VDDDET)
V
HYS
DET
. When the supply voltage returns to a higher voltage than the
SS
’ or ’V
DD
SS
V
DET
’ respectively. It monitors the voltage level of the supply
2.7V
min.
DD
DET
’) or V
DET
V
+V
/40
Limit Values
DD
+V
the microcontroller clock MCLK is stopped (MCLK
HYS
=3.3V±5%
HYS
DD
the internal reset is released and the MCLK is
161
= 5V (Pin VDDSEL = ’V
) the reset is released if the deactivation time
V
max.
2.9V
DD
/30
DET
and the hysteresis V
V
min.
4.2V
DD
/40
Limit Values
V
DD
DD
’) respectively are
ACT
=5V±5%
is 10 µs. The
PSB 21391
PSB 21393
V
2001-03-07
max.
4.5V
DD
/30
HYS
Reset
for