Datasheet

TPS2231
TPS2236
SLVS536J –JULY 2004–REVISED SEPTEMBER 2009.................................................................................................................................................. www.ti.com
SYSRST
This input is driven by the host system and directly affects PERST. Asserting SYSRST (logic low) forces PERST
to assert. RCLKEN is not affected by the assertion of SYSRST. SYSRST has an internal pullup connected to
AUXIN.
OC
This pin is an open-drain output. When any of the three power switches (AUX, 3.3V, and 1.5V) is in an
overcurrent condition, OC is asserted (logic low) by an internal discharge FET with a deglitch delay. Otherwise,
the discharge FET is open, and the pin can be pulled up to a power supply through an external resistor.
FUNCTIONAL TRUTH TABLES
Truth Table for Voltage Outputs
VOLTAGE INPUTS
(1)
LOGIC INPUTS VOLTAGE OUTPUTS
(2)
MODE
(3)
AUXIN 3.3VIN 1.5VIN SHDN STBY CP
(4)
AUXOUT 3.3VOUT 1.5VOUT
Off x x x x x Off Off Off OFF
On x x 0 x x GND GND GND Shutdown
On x x 1 x 1 GND GND GND No Card
On On On 1 0 0 On Off Off Standby
On On On 1 1 0 On On On Card Inserted
(1) For input voltages, On means the respective input voltage is higher than its turnon threshold voltage; otherwise, the voltage is Off (for
AUX input,Off means the voltage is close to zero volt).
(2) For output voltages, On means the respective power switch is turned on so the input voltage is connected to the output; Off means the
power switch and its output discharge FET are both off; GND means the power switch is off but the output discharge FET is on so the
voltage on the output is pulled down to 0 V.
(3) Mode assigns each set of input conditions and respective output voltage results to a different name. These modes are referred to as
input conditions in the following Truth Table for Logic Outputs.
(4) CP = CPUSB and CPPE – equal to 1 when both CPUSB and CPPE signals are logic high, or equal to 0 when either CPUSB or CPPE is
low.
Truth Table for Logic Outputs
INPUT CONDITIONS LOGIC OUTPUTS
MODE SYSRST RCLKEN
(1)
PERST RCLKEN
(2)
OFF
Shutdown
X X 0 0
No Card
Standby
0 Hi-Z 0 1
0 0 0 0
Card Inserted
1 Hi-Z 1 1
1 0 0 0
(1) RCLKEN as a logic input in this column. RCLKEN is an I/O pin and it can be driven low externally, left open, or connected to
high-impedance terminals, such as the gate of a MOSFET. It must not be driven high externally.
(2) RCLKEN as a logic output in this column.
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