User Manual

Host Interface

Rev 1.2 Apr-05 Proprietary and confidential 35

Figure 10: RUIM application interface

MCXXXX

RUIM_PWR

/RUIM_RESET

RUIM_IO

RUIM_CLK

RUIM/SIM card

connector

GND

ESD

protection

0 ohm

4.7uF

X5R

typ

pin 1

pin 3

pin 4

pin 2

pin 8

XIM_VCC

XIM_CLK

XIM_IO

/XIM_RESET

located near

SIM socket

located near

SIM socket

GND

XIM notes of operation

• To save power, the XIM interface should be powered down when not in use.

• XIM is specified to run up to 5 MHz (XIM clock rate). Take note of this

speed in the placement and routing of the XIM signals and connectors.

• To protect the modem CPU, ESD protection is required for XIM_CLK,

XIM_IO, /XIM_DETECT (if used), and /XIM_RESET lines. Additionally

spaces for possible series resistors should be added to the layout. Possible

values of up to 470 ohm may be used depending on ESD testing

requirements.

• It is recommended to put a placeholder capacitor near the SIM socket. The

longer the trace length (impedance) from the socket to the MiniCard, the

greater the capacitance requirement will be to meet compliance tests.