DS1305

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Table 3. TRICKLE CHARGER RESISTOR AND DIODE SELECT

TCS

Bit 7

TCS

Bit 6

TCS

Bit 5

TCS

Bit 4

DS

Bit 3

DS

Bit 2

RS

Bit 1

RS

Bit 0

FUNCTION

X

X

X

X

X

X

0

0

Disabled

X

X

X

X

0

0

X

X

Disabled

X

X

X

X

1

1

X

X

Disabled

1

0

1

0

0

1

0

1

1 Diode, 2kΩ

1

0

1

0

0

1

1

0

1 Diode, 4kΩ

1

0

1

0

0

1

1

1

1 Diode, 8kΩ

1

0

1

0

1

0

0

1

2 Diodes, 2kΩ

1

0

1

0

1

0

1

0

2 Diodes, 4kΩ

1

0

1

0

1

0

1

1

2 Diodes, 8kΩ

0

1

0

1

1

1

0

0

Initial power-on state

The user determines diode and resistor selection according to the maximum current desired for battery or

super cap charging. The maximum charging current can be calculated as illustrated in the following

current decreases.

POWER CONTROL

are illustrated in Figure 4. Configuration 1 shows the DS1305 being backed up by a nonrechargeable

energy source such as a lithium battery. In this configuration, the system power supply is connected to

Configuration 2 illustrates the DS1305 being backed up by a rechargeable energy source. In this case, the

Configuration 3 shows the DS1305 in battery operate mode where the device is powered only by a single

Only these three configurations are allowed. Unused supply pins must be grounded.