DS2703 SHA-1 Battery Pack Authentication IC

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PIN DESCRIPTION

PIN

NAME

FUNCTION

1

THM

Thermistor Mux. Connect a thermistor from THM to DQ. Optional. For temperature

measurements only. If a thermistor is not used in the application, It is recommended THM

be tied to DQ with a 50KΩ resistor instead. THM should never be left floating.

2

VSS

Device Ground. Connect directly to the negative terminal of the battery cell.

3

DQ

Data Input/Output. 1-Wire data line. Open-drain output driver. Connect this pin to the

DATA terminal of the battery pack. This pin has a weak internal pulldown (1µA Typical).

4

VB

Hold-up Supply Bypass Input. Internal power supply to the DS2703 while DQ is low.

5

NC

No Connect. Pin not connected internally, float or connect to VSS.

6

NC

No Connect. Pin not connected internally, float or connect to VSS.

7

NC

No Connect. Pin not connected internally, float or connect to VSS.

8

NC

No Connect. Pin not connected internally, float or connect to VSS.

Figure 1. Block Diagram

1-Wire

Interface

Command

Processor

2 x 32 bit

Rom ID

EEPROM

Write Control

VB

DQ

THM

2 x 32 bit

Challenge

SHA-1

Engine

2 x 32-bit

Secret

MAC Buffer

(Registers

A - E)

VSS

Fixed Data

& Constants

Response

Timing

Generator

To Command

Processor

Driver

V

DD_INT