CAT4003B, CAT4004B

http://onsemi.com

4

Table 4. ELECTRICAL OPERATING CHARACTERISTICS

Parameter

Conditions

Symbol

Min

Typ

Max

Units

Quiescent Current

0.5

0.7

1.5

mA

Shutdown Current

1

mA

Full Scale LED Current (Average) (Note 5)

24

25

26

mA

LED Channel Matching

−5

±1

+5

%

Dropout Voltage

75

45

mV

EN/DIM Pin

− Internal pull−down resistor

− Logic High Level

− Logic Low Level

1.3

200

0.4

kW

V

V

Thermal Shutdown

150

°C

Thermal Hysteresis

20

°C

Undervoltage lockout (UVLO) threshold

2.0

V

6. The Min/Max limits apply across the −40°C to +85°C ambient temperature range and are assured by design, characterization and correlation

with statistical analysis.

Parameter

Conditions

Symbol

Min

Typ

Max

Units

Power−up Setup Time

10

ms

EN/DIM program low time

0.2

500

ms

EN/DIM program high time

0.2

ms

LED current settling time

10

ms

EN/DIM low time to shutdown

2

3

5

ms

7. The Min/Max limits apply across the −40°C to +85°C ambient temperature range and are assured by design, characterization and correlation

with statistical analysis.

Figure 1. CAT400XB EN/DIM Dimming Timing Diagram

100%

EN/DIM

LED

Current

Shutdown

Shutdown

97% 94%

3%

0%

100%

32 Levels

LED Current Setting

On the CAT400XB, the full scale LED current is

internally set to 25 mA (no external resistor).

When the EN/DIM is first enabled, the CAT400XB sets

the LED channel current to the full scale current. Each

consecutive rising edge on the EN/DIM decreases the LED

current by one step until it goes to zero, as shown on

Figure 1.