DS2703G+T&R Maxim Integrated Products, DS2703G+T&R Datasheet - Page 11

• Manufacturer Part Number: DS2703G+T&R
• Description: IC BATT AUTHENTICAT SHA-1 8-TDFN
• Manufacturer: Maxim Integrated Products

Specifications of DS2703G+T&R

• Function: Battery Authentication
• Battery Type: Lithium-Ion (Li-Ion)
• Voltage - Supply: 2.7 V ~ 5.5 V
• Operating Temperature: -20°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 4. 1-Wire CRC Generation Block Diagram
HARDWARE CONFIGURATION
The DS2703 uses an open-drain output driver as part of the bidirectional interface circuitry shown in Figure 5. If a
bidirectional pin is not available on the bus master, separate output and input pins can be connected together. For
normal communication the 1-Wire bus must have a pullup resistor at the bus-master end of the bus. For short line
lengths and/or V
V
reason, a bus transaction must be suspended, the bus must be left in the idle state to properly resume the
transaction later. Note that if the bus is left low for more than t
low period as a reset pulse, effectively terminating the transaction.
When performing SHA-1 computations with a low pullup voltage, the DS2703 may require a stronger pullup than
4.7k to maintain the minimum V
during computation and then disabled to read the result. When measuring the thermistor R
pullup and standard pullup should be disabled to allow a weak pullup to form a voltage divider with the thermistor.
A voltage A/D connected directly to the 1-Wire bus can then read the voltage drop of the thermistor.
Figure 5. 1-Wire Bus Interface Circuitry
PULLUP
< 3.0V, a value of approximately 2kΩ is recommended. The idle state for the 1-Wire bus is high. If, for any
Rx
Tx
Bus Master
Voltage A/D
V
MSb
PULLUP
COMM
COMP
PULLUP
≥ 3.0V, a value of approximately 4.7kΩ is recommended. For long line lengths and/or
PULLUP
requirement. A P-FET in parallel with the standard pullup can be switched on
4.7K
XOR
50K
11 of 20
PACK-
DQ
150
LOW0
R
THM
XOR
, slave devices on the bus begin to interpret the
~1µA
DS2703
~100Ω
MOSFET
LSb
THM
Activate
, both the strong
THM
XOR
INPUT
Rx
Tx