Datasheet MIC5018 Datasheet (MICREL)

MIC5018 Micrel

MIC5018

IttyBitty™ High-Side MOSFET Driver

Preliminary Information

General Description

The MIC5018 IttyBitty™ high-side MOSFET driver is de­signed to switch an N-channel enhancement-type MOSFET
from a TTL compatible control signal in high- or low-side
switch applications. This driver features the tiny 4-lead
SOT-143 package.

The MIC5018 is powered from a +2.7V to +9V supply and
features extremely low off-state supply current. An internal
charge pump drives the gate output higher than the driver
supply voltage and can sustain the gate voltage indefinitely.
An internal zener diode limits the gate-to-source voltage to a
safe level for standard N-channel MOSFETs.

In high-side configurations, the source voltage of the MOS­FET approaches the supply voltage when switched on. To
keep the MOSFET turned on, the MIC5018’s output drives
the MOSFET gate voltage higher than the supply voltage. In
a typical high-side configuration, the driver is powered from
the load supply voltage. Under some conditions, the MIC5018
and MOSFET can switch a load voltage that is slightly higher
than the driver supply voltage.

In a low-side configuration, the driver can control a MOSFET
that switches any voltage up to the rating of the MOSFET.
The gate output voltage is higher than the typical 3.3V or 5V
logic supply and can fully enhance a standard MOSFET.

The MIC5018 is available in the SOT-143 package and
is rated for –40°C to +85°C ambient temperature range.

Features

• +2.7V to +9V operation

• 150µA typical supply current at 5V supply

• ≤ 1µA typical standby (off) current

• Charge pump for high-side low-voltage applications

• Internal zener diode gate-to-ground MOSFET protection

• Operates in low- and high-side configurations

• TTL compatible input

• ESD protected

Applications

• Battery conservation

• Power bus switching

• Solenoid and motion control

• Lamp control

Ordering Information

Part Number Temp. Range Package Marking

MIC5018BM4 –40°C to +85°C SOT-143 H10

5

Typical Applications

+5V

4.7µF

On
Off

MIC5018

23

VS

4

CTLGGND

* International Rectifier

100m

Ω

, 17A max.

TO-220 package

1

Low-Voltage High-Side Power Switch

1997 5-155

IRFZ24*
N-Channel
MOSFET

Load

‡

Load voltage limited only by
MOSFET drain-to-source rating

* Siliconix

30m

Ω

, 7A max., 30V VDS max.

8-lead SOIC package

+2.7 to +9V

4.7µF

On
Off

23

VS

4

CTLGGND

Low-Side Power Switch

MIC5018

V

LOAD SUPPLY

1

‡

Load

Si9410DY*
N-channel
MOSFET

MIC5018 Micrel

Pin Configuration

Identification

Part

Early production identification:

MH10

Pin Description

Pin Number Pin Name Pin Function

1 GND Ground: Power return.
2 VS Supply (Input): +2.7V to +9V supply.
3 G Gate (Output): Gate connection to external MOSFET.
4 CTL Control (Input): TTL compatible on/off control input. Logic high drives the

VS

GND

12

H10

34

CTLG

SOT-143 (M4)

gate output above the supply voltage. Logic low forces the gate output near
ground.

5-156 1997

MIC5018 Micrel

Absolute Maximum Ratings

Supply Voltage (V

SUPPLY

Control Voltage (V

Gate Voltage (VG) .......................................................+16V

Ambient Temperature Range (TA) ............. –40°C to +85°C

)...........................................+10V

) ................................. –0.6V to +16V

CTL

Lead Temperature, Soldering 10sec......................... 300°C

Package Thermal Resistance

SOT-143 θJA.....................................................220°C/W

SOT-143 θJC.....................................................130°C/W

Electrical Characteristics

Parameter Condition (Note 1) Min Typ Max Units

Supply Current V

V

Control Input Voltage 2.7V ≤ V

2.7V ≤ V

5V ≤ V
Control Input Current 2.7V ≤ V
Control Input Capacitance Note 2 5pF
Zener Diode Output Clamp V
Gate Output Voltage V

V

V
Gate Output Current V
Gate Turn-On Time V

Gate Turn-Off Time V

= 3.3V V

SUPPLY

= 5V V

SUPPLY

≤ 9V V

SUPPLY

≤ 5V V

SUPPLY

≤ 9V V

SUPPLY

≤ 9V 0.01 1 µA

SUPPLY

= 9V 13 16 19 V

SUPPLY

= 2.7V 6.3 7.1 V

SUPPLY

= 3.0V 7.1 8.2 V

SUPPLY

= 4.5V 11.4 13.4 V

SUPPLY

= 5V V

SUPPLY

= 4.5V CL = 1000pF, Note 4 0.75 1.5 ms

SUPPLY

= 0V 0.01 1 µA

CTL

V

= 3.3V 70 140 µA

CTL

= 0V 0 1 µA

CTL

V

= 5V 150 300 µA

CTL

for logic 0 input 0 0.8 V

CTL

for logic 1 input 2.0 V

CTL

for logic 1 input 2.4 V

CTL

= 10V, Note 3 9.5 µA

OUT

CL = 3000pF, Note 4 2.1 4.2 ms

= 4.5V CL = 1000pF, Note 5 10 20 µs

SUPPLY

CL = 3000pF, Note 5 30 60 µs

SUPPLY
SUPPLY

V
V

5

General Note: Devices are ESD protected, however handling precautions are recommended.
Note 1: Typical values at TA = 25°C. Minimum and maximum values indicate performance at –40°C ≥ TA ≥ +85°C. Parts production tested at 25°C.
Note 2: Guaranteed by design.
Note 3: Resistive load selected for V
Note 4: Turn-on time is the time required for gate voltage to rise to 4V greater than the supply voltage. This represents a typical MOSFET gate

threshold voltage.

Note 5: Turn-off time is the time required for the gate voltage to fall to 4V above the supply voltage. This represents a typical MOSFET gate threshold

voltage.

OUT

= 10V.

Test Circuit

V

SUPPLY

0.1µF

5V
0V

MIC5018

23

VS

4

CTLGGND

1

V

C

L

OUT

1997 5-157

MIC5018 Micrel

Typical Characteristics Note 4

Supply Current

vs. Supply Voltage

1.0

0.8

0.6

0.4

0.2

SUPPLY CURRENT (mA)

0

0246810

SUPPLY VOLTAGE (V)

-40°C

25°C

125°C

Gate Output Voltage

vs. Supply Voltage

20

15

10

5

OUTPUT VOLTAGE (V)

0

0246810

SUPPLY VOLTAGE (V)

125°C

-40°C

25°C

Full Turn-On Time

vs. Load Capacitance

20

Note 5

15

V

= 3V

10

5

TURN-ON TIME (ms)

0

0 1000 2000 3000 4000 5000

SUPPLY

5V

CAPACITANCE (pF)

Gate Output Current

vs. Output Voltage

160

120

V

80

40

OUTPUT CURRENT (µA)

5V

3V

0

0246810121416

OUTPUT VOLTAGE (V)

SUPPLY

= 9V

9V

Full Turn-Off Time

vs. Load Capacitance

8
7

Note 6

6

V

5
4
3
2

TURN-OFF TIME (µs)

1
0

0 1000 2000 3000 4000 5000

= 3V

SUPPLY

CAPACITANCE (pF)

Gate Output Current

vs. Output Voltage

120

100

80

60

40

20

OUTPUT CURRENT (µA)

0

0246810121416

TA = -55°C

25°C

125°C

OUTPUT VOLTAGE (V)

5V

9V

Note 4: TA = 25°C, V

= 5V unless noted.

SUPPLY

Note 5: Full turn-on time is the time between V
Note 6: Full turn-off time is the time between V

rising to 2.5V and the VG rising to 90% of its steady on-state value.

CTL

falling to 0.5V and the VG falling to 10% of its steady on-state value.

CTL

5-158 1997

MIC5018 Micrel

Functional Diagram

+2.7V to +9V

VS

I1

Q2

R2
15k

20µA

EN

CHARGE

PUMP

D2
35V

Q1

On
Off

CTL

R1 2k

D1
16V

MIC5018

G

D3 16V

Q3

GND

Load

Functional Diagram with External Components

(High-Side Driver Configuration)

5

Functional Description

Refer to the functional diagram.
The MIC5018 is a noninverting device. Applying a logic high

signal to CTL (control input) produces gate drive output. The
G (gate) output is used to turn on an external N-channel
MOSFET.

Supply

VS (supply) is rated for +2.7V to +9V. An external capacitor
is recommended to decouple noise.

Control

CTL (control) is a TTL compatible input. CTL must be forced
high or low by an external signal. A floating input may cause
unpredictable operation.

A high input turns on Q2, which sinks the output of current
source I1, making the input of the first inverter low. The
inverter output becomes high enabling the charge pump.

Charge Pump

The charge pump is enabled when CTL is logic high. The
charge pump consists of an oscillator and voltage quadrupler

(4×). Output voltage is limited to 16V by a zener diode. The
charge pump output voltage will be approximately:

VG = 4 × V

SUPPLY

– 2.8V, but not exceeding 16V.

The oscillator operates from approximately 70kHz to approxi­mately 100kHz depending upon the supply voltage and
temperature.

Gate Output

The charge pump output is connected directly to the G (gate)
output. The charge pump is active only when CTL is high.
When CTL is low, Q3 is turned on by the second inverter and
discharges the gate of the external MOSFET to force it off.

If CTL is high, and the voltage applied to VS drops to zero, the
gate output will be floating (unpredictable).

ESD Protection

D1 and D2 clamp positive and negative ESD voltages. R1
isolates the gate of Q2 from sudden changes on the CTL
input. Q1 turns on if the emitter (CTL input) is forced below
ground to provide additional input protection. Zener D3 also
clamps ESD voltages for the gate (G) output.

1997 5-159

MIC5018 Micrel

Application Information

Supply Bypass

A capacitor from VS to GND is recommended to control
switching and supply transients. Load current and supply
lead length are some of the factors that affect capacitor
size requirements.

A 4.7µF or 10µF aluminum electrolytic or tantalum capacitor
is suitable for many applications.

The low ESR (equivalent series resistance) of tantalum
capacitors makes them especially effective, but also makes
them susceptible to uncontrolled inrush current from low
impedance voltage sources (such as NiCd batteries or auto­matic test equipment). Avoid instantaneously applying volt­age, capable of high peak current, directly to or near tantalum
capacitors without additional current limiting. Normal power
supply turn-on (slow rise time) or printed circuit trace resis­tance is usually adequate for normal product usage.

MOSFET Selection

The MIC5018 is designed to drive N-channel enhancement­type MOSFETs. The gate output (G) of the MIC5018 pro­vides a voltage, referenced to ground, that is greater than the
supply voltage. Refer to the “Typical Characteristics: Gate
Output Voltage vs. Supply Voltage” graph.

The supply voltage and the MOSFET drain-to-source
voltage drop determine the gate-to-source voltage.

VGS = VG – (V

SUPPLY

where:

VGS = gate-to-source voltage (enhancement)
VG = gate voltage (from graph)
V

SUPPLY

= supply voltage

VDS = drain-to-source voltage (approx. 0V at

low current, or when fully enhanced)

– VDS)

V

SUPPLY

across an IRFZ24 is less than 0.1V with a 1A load and 10V
enhancement. Higher current increases the drain-to-source
voltage drop, increasing the gate-to-source voltage.

+5V

4.7µF

Logic

High

MIC5018

23

VS

4

CTLGGND

Voltages are approximate
* International Rectifier

standard MOSFET

15V

1

10V

5V

IRFZ24*

To demonstrate
this circuit, try a
2

Ω

, 20W

Load

load resistor .

approx. 0V

Figure 2. Using a Standard MOSFET

The MIC5018 has an internal zener diode that limits the gate­to-ground voltage to approximately 16V.

Lower supply voltages, such as 3.3V, produce lower gate
output voltages which will not fully enhance standard
MOSFETs. This significantly reduces the maximum current
that can be switched. Always refer to the MOSFET data sheet
to predict the MOSFET’s performance in specific applica­tions.

Logic-Level MOSFET

Logic-level N-channel MOSFETs are fully enhanced with a
gate-to-source voltage of approximately 5V and generally
have an absolute maximum gate-to-source voltage of ±10V.

+3.3V

4.7µF

Logic

High

MIC5018

23

VS

4

CTLGGND

Voltages are approximate
* International Rectifier

logic-level MOSFET

9V

1

5.7V

3.3V

IRLZ44*

To demonstrate
this circuit, try
5

Ω

, 5W or

47

Ω

, 1/4W

Load

load resistors.

approx. 0V

MIC5018

23

VS

4

CTLGGND

1

V

GG

V

LOAD

D

V

DS

S

V

GS

Load

Figure 1. Voltages

The performance of the MOSFET is determined by the gate­to-source voltage. Choose the type of MOSFET according to
the calculated gate-to-source voltage.

Standard MOSFET

Standard MOSFETs are fully enhanced with a gate-to-source
voltage of about 10V. Their absolute maximum gate-to­source voltage is ±20V.

With a 5V supply, the MIC5018 produces a gate output of
approximately 15V. Figure 2 shows how the remaining
voltages conform. The actual drain-to-source voltage drop

Figure 3. Using a Logic-Level MOSFET

Refer to figure 3 for an example showing nominal voltages.
The maximum gate-to-source voltage rating of a logic-level
MOSFET can be exceeded if a higher supply voltage is used.
An external zener diode can clamp the gate-to-source volt­age as shown in figure 4. The zener voltage, plus its
tolerance, must not exceed the absolute maximum gate
voltage of the MOSFET.

V

SUPPLY

MIC5018

23

VS

4

CTLGGND

5V < VZ < 10V

Protects gate of

logic-level MOSFET

1

Logic-level
N-channel
MOSFET

Load

Figure 4. Gate-to-Source Protection

5-160 1997

MIC5018 Micrel

A gate-to-source zener may also be required when the
maximum gate-to-source voltage could be exceeded due to
normal part-to-part variation in gate output voltage. Other
conditions can momentarily increase the gate-to-source volt­age, such as turning on a capacitive load or shorting a load.

Inductive Loads

Inductive loads include relays, and solenoids. Long leads
may also have enough inductance to cause adverse effects
in some circuits.

+2.7V to +9V

4.7µF

On
Off

MIC5018

23

VS

4

CTLGGND

1

Schottky
Diode

Figure 5. Switching an Inductive Load

Switching off an inductive load in a high-side application
momentarily forces the MOSFET source negative (as the
inductor opposes changes to current). This voltage spike can
be very large and can exceed a MOSFET’s gate-to-source
and drain-to-source ratings. A Schottky diode across the
inductive load provides a discharge current path to minimize
the voltage spike. The peak current rating of the diode should
be greater than the load current.

In a low-side application, switching off an inductive load will
momentarily force the MOSFET drain higher than the supply
voltage. The same precaution applies.

Split Power Supply

Refer to figure 6. The MIC5018 can be used to control a 12V
load by separating the driver supply from the load supply.

+12V

15V

1

12V

IRLZ44*

3V

Load

approx. 0V

To demonstrate
this circuit, try a
40

Ω

, 5W or

100

Ω

, 2W

load resistor.

4.7µF

Logic

High

+5V

MIC5018

23

VS

4

CTLGGND

Voltages are approximate
* International Rectifier

logic-level MOSFET

Figure 6. 12V High-Side Switch

A logic-level MOSFET is required. The MOSFET’s maximum
current is limited slightly because the gate is not fully en­hanced. To predict the MOSFETs performance for any pair
of supply voltages, calculate the gate-to-source voltage and
refer to the MOSFET data sheet.

VGS = VG – (V

LOAD SUPPLY

– VDS)

VG is determined from the driver supply voltage using the
“Typical Characteristics: Gate Output Voltage vs. Supply
Voltage” graph.

Low-Side Switch Configuration

The low-side configuration makes it possible to switch a
voltage much higher than the MIC5018’s maximum supply
voltage.

+80V

* International Rectifier

+2.7 to +9V

4.7µF

On
Off

standard MOSFET
BV

= 100V

DSS

MIC5018

23

VS

4

CTLGGND

1

To demonstrate
this circuit, try
1k, 10W or
33k, 1/4W

Load

load resistors.

IRF540*
N-channel
MOSFET

5

1997 5-161

Figure 7. Low-Side Switch Configuration

The maximum switched voltage is limited only by the
MOSFET’s maximum drain-to-source ratings.