TDA8030 Philips Semiconductors, TDA8030 Datasheet - Page 30

• Manufacturer Part Number: TDA8030
• Description: USB smart card reader (OTP or ROM)
• Manufacturer: Philips Semiconductors

Philips Semiconductors
8.2.4
The switched supply voltage (V
voltage supervisor, to ensure proper Power-on reset when
the reader is plugged into the USB-bus, to maintain all
cards contacts inactive during power-on and also to
enforce an emergency deactivation sequence in case of
V
USB-bus.
The voltage supervisor generates an alarm pulse, whose
length is defined by an external capacitor tied to the
CDELAY pin, when V
operation (1 ms per 2 nF typical).
2003 Jul 04
handbook, full pagewidth
DD
USB smart card reader (OTP or ROM)
drop-out or when the reader is unplugged from the
S
V th1
V DD
V th2
CDELAY
RESET
SUPL
INT0
UPPLY SUPERVISOR
power-on
DD
is too low to ensure proper
DD
) is surveyed by a
t w
Fig.8 Voltage supervisor.
supply dropout
30
This pulse is used as a Power-on reset pulse and also to
either block any spurious spikes on card contacts during
microcontrollers reset, or to force an automatic
deactivation of the contacts in the event of supply
drop-out; see Sections 8.3.3 and 8.3.4.
After power-on, or after a voltage drop, bit SUPL is set
within the Hardware Status Register (HSR) and remains
set until HSR is readout outside the alarm pulse. As long
as the Power-on reset is active, INT0 is LOW.
The same events occurs when the RESET pin has been
set active; the RESET pin should be set HIGH for a
minimum of 100 s for a proper reset.
t w
status read
reset by pin RESET
t w
TDA8030; TDA8031
power- off
Product specification
MGU888