LP3925 Datasheet, PDF (39/51 Pages) Texas Instruments – High Performance Power Management Unit for Handset Applications

USIM Interface
LP3925 includes a SIM/RUIM card interface level-shifter
function. This can be used, if the processor I/O voltage and
SIM card I/O voltage have different values. The interface in-
cludes pins for 3 signals: reset, clock and data. Reset and
clock are unidirectional control signals, going from the pro-
cessor to the SIM card. Data signal is bidirectional.
The SIM card side of the level shifter is always supplied by
LDO8. The processor side supply is user-selectable between
Buck2, LDO1 and LDO11. If the level shifter is enabled, then
the supplies on both sides must be 1.5V or higher to ensure
proper operation.
USIM LEVEL TRANSLATOR ELECTRICAL CHARACTERISTICS
Unless otherwise noted, C_LDOx = C_{VIN_CHG}+C_VBUS+C_VTRM = 1µF. Typical values and limits appearing in normal type apply for T_J =
25°C. Limits appearing in boldface type apply over the entire junction temperature range for operation, T_J = −40°C to +125°C.
Unless otherwise specified, the following applies for V_BATT = 3.6V. (Note 6)
Symbol
Parameter
Conditions
Limits
Typ
Units
Min
Max
V_ILS
Input low threshold
RST_IN, CLK_IN Logic Inputs, LDO1
supply selected
V_IHS
Input high threshold
0.25*
V_LDO1
V
0.75*
V_LDO1
V_OLS
V_OHS
Output Low Level
Output High Level
SIM_RST, SIM_CLK Logic Outputs
0.25*
V_LDO8
V
0.75*
V_LDO8
R_INPU
SIM_IO pullup resistor
10
KΩ
V_{IL_SIM_IO}
Input Low
0.3
V_{IH_SIM_IO}
V_{OL_SIM_IO}
Input High
Output Low Level when
SIM_DATA=GND
SIM_IO
V_DD-0.6V
0.25*
V
V_LDO8
V_{OH_SIM_IO}
Output High Level
0.75*
V_LDO8
R_SPU
SIM_DATA pullup resistor
20
13
KΩ
V_{IL_SIM_DATA}
Input Low
0.3
V_{IH_SIM_DATA}
V_{OL_SIM_DATA}
Input High
Output Low Level when
SIM_IO=GND
SIM_DATA, LDO1 supply selected
0.75*
V_LDO1
0.25*
V
V_LDO1
V_{OH_SIM_DATA}
Output High Level
0.75*
V_LDO1
Timing
Clock Frequency
(Note 7)
20
5
MHz
39
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