MIC3838_05 Datasheet, PDF (5/11 Pages) Micrel Semiconductor – Flexible Push-Pull PWM Controller

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
Operating Supply Current
V_DD Zener Shunt Voltage
V_DD < Start Threshold (MIC3839)
FB = 0V, Ramp = I_LIM = 0V, Notes 11, 12
I_DD = 10mA, Note 13
130 260
µA
1.5
2
mA
13
14
15
V
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Note 7.
Note 8.
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
Maximum operating voltage is equal to the V_DD (zener) shunt voltage. When operating at or near the shunt voltage, care must be taken to limit
the V_DD pin current less than the 20mA V_DD maximum current rating.
Specification for packaged product only.
Measured at RC.
COMP pin is internally clamped to 3.65V(typ.). COMP pin source current is measured at V_COMP = 3.0V to avoid interferring with clamp.
Minimum source current is higher as V_COMP approaches V_CLAMP.
∆V_COMP
Gain is defined by A = _∆VCS , 0 ≤ V_CS ≤ 0.4V.
Note 9. Parameter measured at trip point of latch with FB at 0V
Note 10. The internal current sink on the Ramp and I_LIM pin are designed to discharge an external filter capacitor. It is not intended to be a DC sink
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_DD above the start threshold before setting at 10V.
Note 12. Does not include current in the external oscillator network.
Note 13. Start threshold and Zener Shunt threshold track one another.
April 2005
5
MIC3838/3839