Datasheet
DS_8009C_025  73S8009C Data Sheet 
Rev. 1.5    7 
Table 1 describes the pin functions for the device. 
Table 1: 73S8009C Pin Definitions 
Pin 
Name 
Pin 
(QFN32) 
Type 
Equivalent 
Circuit 
Description 
Card Interface 
I/O  22  IO  Figure 16  Card I/O: Data signal to/from card.  Includes a pull-up 
resistor to V
CC.
AUX1  21  IO  Figure 16  AUX1: Auxiliary data signal to/from card. Includes a 
pull-up resistor to V
CC.
AUX2  20  IO  Figure 16  AUX2: Auxiliary data signal to/from card. Includes a 
pull-up resistor to V
CC.
RST  18  O  Figure 15  Card reset: provides reset (RST) signal to card. RST is 
the pass through signal on RSTIN. Internal control logic 
will hold RST low when card is not activated or VCC is 
too low. 
CLK  16  O  Figure 14  Card clock: provides clock signal (CLK) to card. CLK is 
the pass through of the signal on pin CLKIN.  Internal 
control logic will hold CLK low when card is not 
activated or VCC is too low. 
PRES  14  I  Figure 18  Card Presence switch: active high indicates card is 
present.  Should be tied to GND when not used, but it 
Includes a high-impedance pull-down current source. 
PRES  13  I  Figure 18  Card Presence switch: active low indicates card is 
present.  Should be tied to V
DD
 when not used, but it 
Includes a high-impedance pull-up current source. 
VCC  19  PSO  Figure 13  Card power supply – logically controlled by sequencer, 
output of LDO regulator. Requires an external 0.47 µF 
low ESR filter capacitor to GND. 
GND  17  GND  –  Card ground. 
Miscellaneous Inputs and Outputs
CLKIN  7  I  Figure 18  Clock signal source for the card clock. 
TEST1  10 
– 
– 
Factory test pin. This pin must be tied to GND in 
typical applications. 
TEST2  30 
– 
– 
Factory test pin. This pin must be tied to GND in 
typical applications. 
Power Supply and Ground
VDD  29  PSO 
Figure 13  System interface supply voltage and supply voltage for 
companion controller circuitry. Requires a minimum of 
two 0.1 µF capacitors to ground for proper decoupling. 
VPC  26  PSI 
Figure 13  Power supply source for main voltage converter circuit. 
A 10 µF and a 0.1 µF ceramic capacitor must be 
connected to this pin. 
VBAT  25   
  Alternate power source input, typically from two series 
cells, V > 4 V. 










