August 2003

5

MIC3838/3839

MIC3838/3839

Micrel

Parameter

Condition

Min

Typ

Max

Units

Undervoltage Lockout Section

Start Threshold

MIC3838, Note 11

11.5

12.5

13.5

V

MIC3839

4.1

4.3

4.5

V

Minimum Operating Voltage

MIC3838

7.6

8.3

9

V

After Start

MIC3839

3.9

4.1

4.3

V

Hysteresis

MIC3838

3.5

4.2

5.1

V

MIC3839

0.1

0.2

0.3

V

Soft Start Section

COMP Rise Time

FB = 1.8V, Rise from 0.5V to 3V

2.5

20

ms

Overall Section

Startup Current

V

130

260

µA

Operating Supply Current

FB = 0V, Ramp = I

1.5

2

mA

V

I

13

14

15

V

Note 1.

Exceeding the absolute maximum rating may damage the device.

Note 2.

The device is not guaranteed to function outside its operating rating.

Note 3.

Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.

Note 4.

Maximum operating voltage is equal to the V

the V

Note 5.

Specification for packaged product only.

Note 6.

Measured at RC.

Note 7.

COMP pin is internally clamped to 3.65V(typ.). COMP pin source current is measured at V

Minimum source current is higher as V

Note 8.

Gain is defined by A =

∆

∆

V

V

COMP

CS

, 0

≤ V

Note 9.

Parameter measured at trip point of latch with FB at 0V

Note 10. The internal current sink on the Ramp and I

path. Internal discharge FET should be able to discharge the Volt-Sec clamp and feed-forward circuits in the figure below within 50ns.

Note 11. For MIC3838, set V

Note 12. Does not include current in the external oscillator network.

Note 13. Start threshold and Zener Shunt threshold track one another.