ELECTRICAL CHARACTERISTICS (continued)

BATT-, not GND.)

Note 1: The MAX712/MAX713 are powered from the V+ pin. Since V+ shunt regulates to +5V, R1 must be small enough to allow at

least 5mA of current into the V+ pin.

Note 2: Offset voltage of THI and TLO comparators referred to TEMP.

Note 4: This specification can be violated when attempting to charge more or fewer cells than the number programmed. To ensure

proper voltage-slope fast-charge termination, the (maximum battery voltage) ÷ (number of cells programmed) must fall

within the A/D input range.

NiCd/NiMH Battery

Fast-Charge Controllers

_______________________________________________________________________________________

3

Battery voltage ÷ number of cells programmed

CONDITIONS

V

1.4

1.9

A/D Input Range (Note 4)

µA

10

FASTCHG High Current

mA

2

FASTCHG Low Current

UNITS

MIN

TYP

MAX

PARAMETER

Typical Operating Characteristics

20

1k

100k

1M

10k

10M

CURRENT-SENSE AMPLIFIER

FREQUENCY RESPONSE (with 15pF)

-20

FREQUENCY (Hz)

-10

0

10

40

-120

-80

-40

0

C2 = 15pF

FASTCHG = 0V

CURRENT-

SENSE

AMP

BATT-

BATT-

CC

GND

-

-

+

+

Φ

MAX712/13 toc01

20

-10

-20

10

1k

CURRENT-SENSE AMPLIFIER

FREQUENCY RESPONSE (with 10nF)

0

10

40

-80

-120

-40

0

FREQUENCY (Hz)

100

10k

C2 = 10nF

FASTCHG = 0V

Φ

MAX712/13 toc02

100

0.1

1.95

1.97

2.01

2.05

CURRENT ERROR-AMPLIFIER

TRANSCONDUCTANCE

1

10

VOLTAGE ON CC PIN (V)

1.99

2.03

FASTCHG = 0V, V+ = 5V

5.8

4.8

060

SHUNT-REGULATOR VOLTAGE

vs. CURRENT

5.6

CURRENT INTO V+ PIN (mA)

30

5.2

5.0

10

20

50

5.4

4.0

4.4

4.2

4.6

40

DRV NOT SINKING CURRENT

DRV SINKING CURRENT

1.0

060

ALPHA SENSORS PART No. 14A1002

STEINHART-HART INTERPOLATION

1.6

BATTERY TEMPERATURE(

°C)

30

1.4

1.2

10

20

50

0.2

0.6

0.4

0.8

20

35

30

25

0

10

5

15

40

MAX712/13 toc05