73S8009CN-32IM/F Maxim Integrated Products, 73S8009CN-32IM/F Datasheet - Page 17

• Manufacturer Part Number: 73S8009CN-32IM/F
• Description: IC PWR MGMT/SMART CARD INT 32QFN
• Manufacturer: Maxim Integrated Products

Specifications of 73S8009CN-32IM/F

• Applications: Smart Card Reader, Writer
• Voltage - Supply: 3 V ~ 3.6 V
• Package / Case: 32-VFQFN Exposed Pad
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Interface: -

DS_8009CN_026
Important Notes:
1. When the host is not powered by the V
2. For applications where ON/OFF is controlled by the host, the OFF_REQ and OFF_ACK signals do
3. If the host is capable of selectively monitoring the I/O line, it can be used in place of the V
4. When the 73S8009CN is powered OFF, the host will not be able to detect a card event (card
5. For systems that do not use VDD to power the host controller, the host interface signals must operate
6. The ON/OFF pin is internally pulled up to V
7. For those systems that require low power operation or are battery operated, the host controller circuit
Rev. 1.4
as the host signals going to the 73S8009CN can be active when the device is powered OFF.
This can create issues such as excessive current drain on the control signals and potentially
prohibit proper turn ON of the 73S8009CN. Series resistors on the input signals (except the
ON/OFF input) are recommended to provide isolation and prevent any potential problems.
The recommended value of these resistors is 47kΩ. It is also necessary for the host to set
these input signals to the low state (except for ON/OFF) when the 73S8009CN is OFF. False
activation of the card is possible if the CMDVCC# or CMDVCC% inputs are low (with a card
inserted) when the 73S8009CN is powered ON. For this reason, the proper sequencing of the
73S8009CN is required. The CMDVCC# or CMDVCC% inputs must be set high immediately
before the ON/OFF input is taken low to turn on the 73S8009CN. The time between setting the
CMDVCC# or CMDVCC% inputs high and the setting of the ON/OFF input set low should be
kept to a minimum as the CMDVCC# or CMDVCC% inputs, when set high with the 73S8009CN
OFF, will draw significant current under these conditions. The 47kΩ series resistors will
mitigate this current draw. However, some additional current will be drawn through the
resistors to the CMDVCC# or CMDVCC% inputs during this time so it should be kept to a
minimum.
not need to be connected to the host. When the OFF_ACK pin is left unconnected, the 73S8009CN
will turn off properly by the action of the internal resistor connection to OFF_REQ.
monitor as it is tied to the V
activated.
insertion/removal). If this function is necessary, then the host must monitor the card connector switch
separately.
at 3.3V as the 73S8009CN digital logic operates off the V
the V
the host signal controlling the ON/OFF signal is running at a voltage different from V
case, then either the host control signal must be a maximum V
an external circuit should provide some isolation between the host control signal and the ON/OFF pin.
firmware should place the 73S8009CN in the OFF state if no card activity is required.
PC
supply.
DD
supply through a pull up resistor when the smart card interface is not
DD
PC
supply of the 73S8009CN, special care must be taken
through a 24kΩ resistor. Special care must be taken if
DD
(3.3V) supply regardless of the value of
PC
supply tolerant open drain output or
73S8009CN Data Sheet
PC
. If this is the
DD
supply
17