TDA8006 Datasheet, PDF (25/40 Pages) NXP Semiconductors – Multiprotocol IC Card coupler

Philips Semiconductors
Multiprotocol IC Card coupler
Product specification
TDA8006
Deactivation sequence
When the session has completed, the microcontroller sets
CMDVCC LOW (t₁₀). The circuit then executes an
automatic deactivation sequence:
• Card reset (RST goes LOW) (t₁₁)
• Clock is stopped (t₁₂)
• I/O goes LOW (t₁₃)
• V_CC falls to 0 V with typically 0.16 V/µs slew rate (t₁₄)
• The step-up converter is stopped and CLK, RST, V_CC
and I/O become low impedance to GND (t₁₅).
t₁₁ = t₁₀ + ¹â„₆₄T, t₁₂ = t₁₁ + ¹â„₂T, t₁₃ = t₁₁ + T,
t₁₄ = t₁₁ + ³â„₂T, t₁₅ = t₁₁ + 5T.
t_de is the time that V_CC requires to fall to less than 0.3 V.
handbook, full pagewidth
CMDVCC
RST
CLK
I/O
VCC
VUP
t10
t11
t12
t13
t14
t15
tde
MGR237
Fig.13 Deactivation sequence.
Protection
The main hardware fault conditions monitored by the
circuit are:
• Overcurrent on V_CC
• Short circuits between V_CC and other contacts
• Card take-off during transaction.
When one of these problems is detected, the security logic
block sets the OFF bit LOW which generates an interrupt
warning the microcontroller and initiates an automatic
deactivation of the contacts.
When the deactivation has completed and CMDVCC has
been set LOW, the OFF bit goes HIGH, unless the problem
was caused by a card extraction, in which case it remains
LOW until a card is inserted.
2000 Feb 21
25