MAX1740 Maxim, MAX1740 Datasheet - Page 8

• Manufacturer Part Number: MAX1740
• Description: SIM/Smart Card Level Translators in MAX
• Manufacturer: Maxim

All level translation is valid for DV
V
resistors from DATA to the controller-side supply
(DV
push-pull controller outputs, see the Data Driver section
for bidirectional data translation.
When using a microcontroller (µC) without an open-drain
output, use the data driver (DDRV) input to send data to
the SIM/smart card, while DATA provides the controller-
side output for bidirectional data transfer. When not
used, connect DDRV to DV
rent.
For the MAX1740, drive SHDN low to activate shut-
down. Connect SHDN to DV
operation. To allow for card insertion and removal, shut-
down mode actively pulls CLK, RST, and IO low; it also
disconnects the internal 10kΩ pull-up resistor from V
to prevent excessive current draw. Shutdown mode
reduces the total supply current (I
0.01µA.
The SIM/smart card specifications require that the
card-side pins (V
potential prior to inserting the SIM/smart card. For
applications using the MAX1686H (Figure 4), the easi-
SIM/Smart Card Level Translators
in µMAX
Figure 2. Typical Application Circuit and Functional Diagram
8
CC
*
SHDN FOR MAX1740 ONLY
DDRV FOR MAX1741 ONLY
CC
_______________________________________________________________________________________
. The MAX1740/MAX1741 contain internal pull-up
) and from IO to the card-side supply (V
SIM/Smart Card Insertion/Removal
CONTROLLER
CC
SYSTEM
Data Driver (MAX1741 only)
, CLK, RST, IO) be at ground
DV
GND
CC
CC
OPTIONAL
OPTIONAL
CC
to reduce total supply cur-
or drive high for normal
DV
1µF
CC
CC
Shutdown Mode
CIN
DATA
SHDN*
DDRV*
DV
RIN
DVCC
≥ V
CC
CC
20k
+ I
or DV
CC
VCC
). For
CC
) to
SHUTDOWN
CC
CONTROL
≤
MAX1740
MAX1741
est way to achieve this is by shutting down the
MAX1686H or by driving SHDN (MAX1740 only) low. If
specific sequencing is desired, pull IO low by driving
either DATA or DDRV (MAX1741 only) low, and pull
CLK and RST low by driving CIN and RIN low, respec-
tively.
As with all Maxim devices, ESD-protection structures
on all pins protect against electrostatic discharges
(ESDs) encountered during handling and assembly.
For further protection during card insertion and
removal, the pins that connect to the card socket (CLK,
RST, IO, V
±10kV of ESD, according to the Human Body Model.
The ESD structures withstand high ESD in all states:
normal operation, shutdown, and power-down. After an
ESD event, the MAX1740/MAX1741 continue working
without latchup.
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report documenting test
setup, test methodology, and test results.
Figure 3a shows the Human Body Model, and Figure
3b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of
a 100pF capacitor charged to the ESD voltage of inter-
CC
10k
, and GND) provide protection against
CLK
GND
V
RST
CC
IO
V
CC
1µF
V
RST
CLK
IO
GND
ESD Test Conditions
SMART CARD
CC
Human Body Model
SIM OR
ESD Protection