The TXS4555 device is a Smart Identity
Module (SIM) card option that interfaces wireless baseband processors with a SIM
card to store I/O for mobile handheld applications. The device complies with ISO/IEC
Smart-Card Interface requirements as well as GSM and 3G mobile standards. The device
includes a high-speed level translator that can support Class-B (2.95V) and Class-C
(1.8V) interfaces, and a low dropout (LDO) voltage regulator with output voltages
that are selectable between these interfaces.
The device has two supply voltage
pins. VCC can operate over the full range of 1.65V to 3.3V and VBATT from
2.3 to 5.5V. VPWR is set to 1.8V or 2.95V, and is supplied by an internal LDO. The
integrated LDO accepts input voltages as high as 5.5V and outputs 1.8V or 2.95V at
50mA to the B-side circuitry and to the external SIM card. The TXS4555 enables
system designers to interface low-voltage microprocessors to SIM cards operating at
1.8V or 2.95V.
The TXS4555 incorporates shutdown
sequence for the SIM card pins based on the ISO 7816-3 specification for SIM cards.
During an accidental shutdown of the phone, shutting down the SIM card helps prevent
data corruption. The device has 8 kV HBM protection for the SIM pins and standard 2
kV HBM protection for all other pins.
The TXS4555 device is a Smart Identity
Module (SIM) card option that interfaces wireless baseband processors with a SIM
card to store I/O for mobile handheld applications. The device complies with ISO/IEC
Smart-Card Interface requirements as well as GSM and 3G mobile standards. The device
includes a high-speed level translator that can support Class-B (2.95V) and Class-C
(1.8V) interfaces, and a low dropout (LDO) voltage regulator with output voltages
that are selectable between these interfaces.
The device has two supply voltage
pins. VCC can operate over the full range of 1.65V to 3.3V and VBATT from
2.3 to 5.5V. VPWR is set to 1.8V or 2.95V, and is supplied by an internal LDO. The
integrated LDO accepts input voltages as high as 5.5V and outputs 1.8V or 2.95V at
50mA to the B-side circuitry and to the external SIM card. The TXS4555 enables
system designers to interface low-voltage microprocessors to SIM cards operating at
1.8V or 2.95V.
The TXS4555 incorporates shutdown
sequence for the SIM card pins based on the ISO 7816-3 specification for SIM cards.
During an accidental shutdown of the phone, shutting down the SIM card helps prevent
data corruption. The device has 8 kV HBM protection for the SIM pins and standard 2
kV HBM protection for all other pins.