5

LTC1555/LTC1556

LTC1555/LTC1556

CIN (Pin 1): Clock Input Pin from Controller.

RIN (Pin 2): Reset Input Pin from Controller.

DATA (Pin 3): Controller Side Data Input/Output Pin. Can

be used for single pin bidirectional data transfer between

the controller and the SIM card as long as the controller

data pin is open drain. The controller output must be able

to sink 1mA max when driving the DATA pin low due to

the internal pull-up resistors on the DATA and I/O pins. If

the controller data output is not open drain, then the

DDRV pin should be used for sending data to the SIM

card and the DATA pin used for receiving data from the

SIM card (see Figure 1).

DDRV (Pin 4): Optional Data Input Pin for Sending Data

to the SIM card. When not needed, the DDRV pin should

I/O Pins. May be between 1.8V and 5.5V (typically 3V).

SS (Pins 6/8): Soft Start Enable Pin. A logic low will

enable the charge pump inrush current limiting feature.

A logic high will disable the soft start feature and allow

and coming out of shutdown.

M1 (Pins 7/9): Mode Control Bit 1 (see Truth Table).

M0 (Pins 8/10): Mode Control Bit 0 (see Truth Table).

This table defines the various operating modes that may

be obtained via the M0 and M1 mode control pins.

Truth Table

M0

M1

MODE

0V

0V

0V

0V

GND (Pins 9/11, 12): Ground for Both the SIM and the

Controller. Should be connected to the SIM GND contact

and supply bypassing is required to meet 10kV ESD

specifications.

tive Input.

Input.

voltage range is 2.7V to 10V. Connect a 10

µF low ESR

voltage is determined by the M0 and M1 pins (see Truth

(M0, M1 = 0V). A 10

µF low ESR output capacitor should

I/O (Pins 14/18): SIM Side I/O Pin. The pin is an open

drain output with a nominal pull-up resistance of 10k and

should be connected to the SIM I/O contact. The SIM card

must sink up to 1mA max when driving the I/O pin low

due to the internal pull-up resistors on the I/O and DATA

pins. The I/O pin is held active low when the part is in

shutdown.

RST (Pins 15/19): Level Shifted Reset Output Pin. Should

be connected to the SIM RST contact.

CLK (Pins 16/20): Level Shifted Clock Output Pin. Should

be connected to the SIM CLK contact. Careful trace

routing is recommended due to fast rise and fall edge

speeds.