Product data

TDA8007BHL All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 9.1 — 18 June 2012 31 of 51
NXP Semiconductors
TDA8007BHL
Multiprotocol IC card interface
8.3 Supply
The TDA8007BHL/C4 operates within a supply voltage range of 2.7 V 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 decoupled
externally because of the large current spikes that the cards and the step-up converter
can create. V
DDA
may be different from V
DD
.
Pins V
DD
and GND supply the remainder of the chip. An integrated spike killer ensures
that the contacts to the cards remain inactive during power-up and power-down. An
internal voltage reference is generated for use within the step-up converter, the voltage
supervisor and the V
CC
generators.
The voltage supervisor generates an alarm pulse when V
DD
is too low to ensure proper
operation. The alarm pulse length is defined by an external capacitor tied to pin DELAY
and is typically 1 ms per 2 nF.
The alarm pulse may be used as a reset pulse by the system microcontroller
(pin RSTOUT = high). It can also be used to block any spurious noise on card contacts
during the microcontrollers reset, or to force an automatic deactivation of the contacts in
the event of a supply drop-out (see Section 8.5
and 8.7).
After power-on, or after a voltage drop, bit SUPL is set within register HSR and remains
set until register HSR is read-out outside the alarm pulse. Signal INT
= low for the
duration that signal RSTOUT is active.
Fig 17. voltage supervisor
V
th1
V
DD
V
th2
CDELAY
RSTOUT
SUPL
INT
Supply dropout Power-offReset by C
DELAY
Power-on
Status read
fce683
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