4

UC2909

UC3909

PARAMETER

TEST CONDITIONS

MIN

TYP

MAX

UNITS

Voltage Sense Comparator Section (VSC)

Threshold Voltage

0.945

0.95

0.955

V/V

0.895

0.9

0.905

V/V

Over Charge Taper Current Comparator Section (OCTIC)

Threshold Voltage

Function of 2.3V REF, CA- = CAO

0.99

1

1.01

V/V

Input Bias Current

OVCTAP = 2.3V

–0.5

–0.1

µA

Logic 5V Reference Section (VLOGIC)

VLOGIC

VCC = 15V

4.875

5.0

5.125

V

Line Regulation

3

15

mV

Load Regulation

3

15

mV

Reference Comparator Turn-on Threshold

4.3

4.8

V

Short Circuit Current

30

50

80

mA

Output Stage Section

50

mA

100

mA

1

1.3

V

Leakage Current

25

µA

STAT0 & STAT1 Open Collector Outputs Section

Maximum Sink Current

6

10

mA

Saturation Voltage

0.1

0.45

V

Leakage Current

25

µA

STATLV Open Collector Outputs Section

Maximum Sink Current

2.5

5

mA

Saturation Voltage

0.1

0.45

V

Leakage current

3

µA

UVLO Section

Turn-on Threshold

6.8

7.8

8.8

V

Hysteresis

100

300

500

mV

(See Fig. 1)

13

19

mA

VCC = 6.5V

2

mA

Note 2: VIO is measured prior to packaging with internal probe pad.

Note 3: Thermistor initial accuracy is measured and trimmed with respect to VAO; VAO = VA–.

CA–: The inverting input to the current error amplifier.

CAO: The output of the current error amplifier which is

internally clamped to approximately 4V. It is internally

connected to the inverting input of the PWM comparator.

CS–, CS+: The inverting and non-inverting inputs to the

current sense amplifier. This amplifier has a fixed gain of

five and a common-mode voltage range of from –250mV

to +VCC.

CSO: The output of the current sense amplifier which is

internally clamped to approximately 5.7V.

CHGENB: The input to a comparator that detects when

battery voltage is low and places the charger in a trickle

charge state. The charge enable comparator makes the

output of the voltage error amplifier a high impedance

while forcing a fixed 10

µA into CA– to set the trickle

charge current.

PIN DESCRIPTIONS