The TXS02326A is a dual-supply standby Smart Identity Module (SIM) card solution that connects wireless baseband processors to two separate SIM subscriber cards to store data for mobile handset applications. It is a bespoke device that expands a single SIM/UICC interface to handle two SIMs/UICCs. The gadget satisfies GSM and 3G mobile standards in addition to ISO/IEC Smart-Card Interface criteria. Included are two low-dropout (LDO) voltage regulators with output voltages that can be switched between 2.95-V Class-B and 1.8-V Class-C interfaces; a high-speed level translator that supports Class-B (2.95-V) and Class-C (1.8-V) interfaces; an integrated "fast-mode" 400 kb/s "slave" I2C control register interface for configuration; and a 32-kHz clock input for internal timing generation. The two SIM cards can be safely powered down with the help of the TXS02326A's comparator input and shutdown input, which both detect the withdrawal of the battery pack. There are two programmable debounce counter circuits (BSI input and SDN input) on the comparator and shutdown inputs. These circuits are implemented using an 8-bit counter. There are two supply voltage pins on the voltage-level translator. VDDIO, which operates between 1.7 and 3.3 volts, establishes the standard for the baseband interface. VSIM1 and VSIM2 are supplied by separate internal LDO regulators and are tuned to either 1.8-V or 2.95-V. The integrated LDO can receive battery voltages between 2.3 and 5.5 volts and output up to 50 milliamperes of current to the external Class-B or Class-C SIM card and B-side circuitry.
Datasheet
