DS_8023C_019
73S8023C Data Sheet
1 Pin Description
1.1 Card Interface
Name
I/O
Pin
9
Description
Card I/O: Data signal to/from card. Includes a pull-up resistor to VCC.
AUX1: Auxiliary data signal to/from card. Includes a pull-up resistor to VCC.
AUX2: Auxiliary data signal to/from card. Includes a pull-up resistor to VCC.
AUX1
AUX2
11
10
RST
CLK
14
13
Card reset: Provides reset (RST) signal to card.
Card clock: Provides clock (CLK) signal to card. The rate of this clock is
determined by crystal oscillator frequency and CLKDIV selections.
PRES
PRES
VCC
7
6
Card Presence switch: Active high indicates card is present. Includes a
pull-down current source.
Card Presence switch: Active low indicates card is present. Includes a pull-up
current source.
15
12
Card power supply: Logically controlled by sequencer, output of DC-DC
converter. Requires an external filter capacitor to the card GND.
GND
Card ground.
1.2 Miscellaneous Inputs and Outputs
Name
Pin
Description
XTALIN
23
Crystal oscillator input: can either be connected to crystal or driven as a
source for the card clock.
XTALOUT
VDDF_ADJ
NC
24
17
4
Crystal oscillator output: connected to crystal. Left open if XTALIN is being
used as external clock input.
VDD fault threshold adjustment input: this pin can be used to adjust VDDF
value (that controls deactivation of the card). Must be left open if unused.
Non-connected pin. Must be left open.
1.3 Power Supply and Ground
Name
Pin
Description
VDD
3, 20
System controller interface supply voltage: Supply voltage for internal power
supply and DC-DC converter power supply source.
GND
GND
LIN
1
21
2
DC-DC converter ground.
Digital ground.
External inductor. Connect external inductor from pin 2 to VDD. Keep the
inductor close to pin 2.
Rev. 1.5
5