TDA8007B Datasheet, PDF (20/36 Pages) NXP Semiconductors – Double multiprotocol IC card interface

Philips Semiconductors
Double multiprotocol IC card interface
Product specification
TDA8007B
Supply
The circuit operates within a supply voltage range of
2.7 to 6 V. The supply pins are V_DD, V_DDA, GND and
AGND. Pins V_DDA and AGND supply the analog drivers to
the cards and have to be externally decoupled because of
the large current spikes that the cards and the step-up
converter can create. Pins V_DD and GND supply the rest of
the chip. An integrated spike killer ensures that the
contacts to the cards remain inactive during power-up or
power-down. An internal voltage reference is generated
which is used within the step-up converter, the voltage
supervisor and the V_CC generators.
The voltage supervisor generates an alarm pulse, whose
length is defined by an external capacitor tied to pin
DELAY, when V_DD is too low to ensure proper operation
(1 ms per 1 nF typical).
This pulse may be used as a reset pulse by the system
microcontroller (pin RSTOUT, active HIGH). It is also used
in order to either block any spurious noise on card contacts
during the microcontrollers reset, or to force an automatic
deactivation of the contacts in the event of supply dropout
(see Sections “Activation sequence” and “Deactivation
sequence”).
After Power-on, or after a voltage drop, bit SUPL is set
within the Hardware Status Register (HSR) and remains
set until HSR is read-out outside the alarm pulse. Pin INT
is LOW for the duration that RSTOUT is active.
If needed, a complete reset of the chip may be performed
by discharging the capacitor C_DELAY.
handbook, full pagewidth_Vth1
VDD
Vth2
CDELAY
RSTOUT
SUPL
INT
Power-on
tw
Status read
Supply dropout
Reset by CDELAY
Power-off
FCE683
Fig.7 Voltage supervisor.
2000 Nov 09
20