MIC5021 Micrel Semiconductor, MIC5021 Datasheet - Page 2

• Manufacturer Part Number: MIC5021
• Description: High-Speed High-Side MOSFET Driver
• Manufacturer: Micrel Semiconductor

MIC5021
Pin Configuration
Block Diagram
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Sense +
Sense –
Transistor: 106
Input
6V Internal Regulator
Pin Name
50mV
Sense +
Sense –
V
C
Input
Gate
BOOST
V
Gnd
INT
C
DD
2I
T
I
1
1
1
2
3
4
Input
C
Gnd
V
DIP Package
T
DD
(N)
Sense
Sense
V
BOOST
Gate
Pin Function
Supply: +12V to +36V. Decouple with
TTL Compatible Input: Logic high turns the external MOSFET on. An
internal pull-down returns an open pin to logic low.
Retry Timing Capacitor: Controls the off time (t
retry cycle. (Duty cycle adjustment.)
• Open = approx. 20% duty cycle.
• Capacitor to Ground = approx. 20% to < 1% duty cycle.
• Pull-up resistor = approx. 20% to approx. 75% duty cycle.
• Ground = maintained shutdown upon overcurrent condition.
Circuit Ground
Current Sense Comparator (+) Input: Connect to high side of sense resistor
or current sensing MOSFET sense lead. A built-in offset in conjunction with
R
Current Sense Comparator (–) Input: Connect to the low side of the sense
resistor (usually the high side of the load).
Gate Drive: Drives the gate of an external power MOSFET. Also limits V
to 15V max. to prevent Gate-to-Source damage. Will sink and source
current.
Charge Pump Boost Capacitor: A bootstrap capacitor from V
FET source pin supplies charge to quickly enhance the Gate output during
turn-on.
SENSE
SHOT
8
7
6
5
ONE-
sets the load overcurrent trip point.
5-170
Fault
Normal
1
2
3
4
SOIC Package
Q1
10I
V
Input
C
Gnd
DD
T
2
(M)
Sense
Sense
V
I
2
BOOST
Gate
ON
OFF
8
7
6
5
6V
CHARGE
PUMP
10 F capacitor.
G(OFF)
15V
C
V
V
Gate
DD
BOOST
T
) of the overcurrent
BOOST
October 1998
to the
GS
Micrel