tda8029hl-c207 NXP Semiconductors, tda8029hl-c207 Datasheet - Page 41

• Manufacturer Part Number: tda8029hl-c207
• Description: Low Power Single Card Reader
• Manufacturer: NXP Semiconductors

Philips Semiconductors
9397 750 14145
Product data sheet
8.11 Supply
8.12 DC-to-DC converter
The circuit operates within a supply voltage range of 2.7 V to 6 V. The supply pins are
V
and have to be externally decoupled because of the large current spikes the card and the
step-up converter can create. V
spike killer ensures the contacts to the card to remain inactive during power-up or -down.
An internal voltage reference is generated which is used within the step-up converter, the
voltage supervisor, and the V
V
The voltage supervisor generates an alarm pulse, whose length is defined by an external
capacitor connected to the CDEL pin, when V
(1 ms per 2 nF typical). This pulse is used as a Power-on reset pulse, and also to block
either any spurious signals on card contacts during controllers reset or to force an
automatic deactivation of the contacts in the event of supply drop-out (see
and
After power-on or after a voltage drop, the bit SUPL is set within the Hardware Status
Register (HSR) and remains set until HSR is read when the alarm pulse is inactive.
As long as the Power-on reset is active, INT0_N is LOW.
The same occurs when leaving Shut-down mode or when the RESET pin has been set
active.
Except for V
by V
ISO contacts supply. When a card session is requested by the controller, the sequencer
first starts the DC-to-DC converter, which is a switched capacitors type, clocked by an
internal oscillator at a frequency of approximately 2.5 MHz.
Fig 11. Voltage supervisor
DD
DCIN
RSTOUT
, DCIN, GND and PGND. Pins DCIN and PGND supply the analog drivers to the cards
Section
DD
CDEL
SUPL
may be higher than V
V
V
V
INT
DD
and DCIN. If the supply voltage is 2.7 V, then a higher voltage is needed for the
th1
th2
power-on
CC
8.17).
generator, and the other card contacts buffers, the whole circuit is powered
Rev. 03 — 22 February 2005
t
w
DD
CC
.
DD
generators.
and GND supply the rest of the chip. An integrated
supply dropout
status read
DD
is too low to ensure proper operation
Low power single card reader
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
reset by CDEL
TDA8029
Section 8.16
power-off
mdb815
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