MIC5011 Micrel Semiconductor, MIC5011 Datasheet - Page 6

• Manufacturer Part Number: MIC5011
• Description: Minimum Parts High- or Low-Side MOSFET Driver
• Manufacturer: Micrel Semiconductor

MIC5011
Block Diagram
Applications Information
Functional Description (Refer to Block Diagram)
The MIC5011 functions are controlled via a logic block
connected to the input pin 2. When the input is low, all
functions are turned off for low standby current and the gate
of the power MOSFET is also held low through 500 to an
N-channel switch. When the input is taken above the turn-
on threshold (3.5V typical), the N-channel switch turns off
and the charge pump is turned on to charge the gate of the
power FET.
MIC5011
250
200
150
100
50
0
Charge Pump
Output Current
0
SUPPLY VOLTAGE (V)
V
5
GATE
10
=V
+
Input
15
V
GATE
VS=V –5V
20
2
+
=V +5V
Ground
4
+
25
LOGIC
30
V+
1
C1 Com C2
8
CHARGE
PUMP
6
7
The charge pump incorporates a 100kHz oscillator and on-
chip pump capacitors capable of charging 1nF to 5V above
supply in 60 s typical. With the addition of 1nF capacitors
at C1 and C2, the turn-on time is reduced to 25 s typical
(see Figure 3). The charge pump is capable of pumping the
gate up to over twice the supply voltage. For this reason, a
zener clamp (12.5V typical) is provided between the gate
pin 5 and source pin 3 to prevent exceeding the V
of the MOSFET at high supplies.
6
500
MIC5011
1.0
0.8
0.6
0.4
0.2
0
12.5V
Charge Pump
Output Current
0
5 Gate
3 Source
SUPPLY VOLTAGE (V)
V
5
GATE
10
=V
+
15
V
GATE
VS=V –5V
C2=1 nF
20
=V +5V
+
+
25
July 2000
30
GS
rating
Micrel