MIC5018

IttyBitty™ High-Side MOSFET Driver

General Description Features

The MIC5018 IttyBitty™ high-side MOSFET driver is • +2.7V to +9V operation
designed to switch an N-channel enhancement-type • 150µA typical supply current at 5V supply
MOSFET from a TTL compatible control signal in high- or
• ≤1µA typical standby (off) current
low-side switch applications. This driver features the tiny
4-lead SOT-143 package. • Charge pump for high-side low-voltage applications
The MIC5018 is powered from a +2.7V to +9V supply • Internal zener diode gate-to-ground MOSFET protection
and features extremely low off-state supply current. • Operates in low- and high-side configurations
An internal charge pump drives the gate output higher • TTL compatible input
than the driver supply voltage and can sustain the gate • ESD protected
voltage indefinitely. An internal zener diode limits the
gate-to-source voltage to a safe level for standard
N-channel MOSFETs. Applications
In high-side configurations, the source voltage of the • Battery conservation
MOSFET approaches the supply voltage when switched
• Power bus switching
on. To keep the MOSFET turned on, the MIC5018’s output
drives the MOSFET gate voltage higher than the supply • Solenoid and motion control
voltage. In a typical high-side configuration, the driver is • Lamp control
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.

Typical Applications
+5V
‡ Load voltage limited only by
VL O AD SU PPL‡Y
MOSFET drain-to-source rating

* Siliconix
4.7µF MIC5018 IRFZ24* 30m , 7A max., 30V VDS max.
Load

2 3 8-lead SOIC package

VS G N-Channel
4 1
MO S F E T +2.7 to +9V
C T L GND
On
Off 4.7µF MIC5018
Si9410DY*
Load

2 3
VS G N-channel
* International Rectifier
100m , 17A max. 4 1 MO S F E T
TO-220 package C T L GND
On
Off

Low-Voltage High-Side Power Switch Low-Side Power Switch

IttyBitty is a trademark of Micrel, Inc.

Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
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Ordering Information
Part Number Making
Temp. Range Package
Standard Pb-Free Standard Pb-Free
MIC5018BM4 MIC5018YM4 H10 H10 –40ºC to +85ºC SOT-143

Pin Configuration
VS GND
2 1
Part
Identification H10
Early production identification: H10
MH10 3 4

G CTL
SOT-143 (M4)

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.
Control (Input): TTL compatible on/off control input. Logic high drives the gate output above the supply
4 CTL
voltage. Logic low forces the gate output near ground.

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Absolute Maximum Ratings Operating Ratings

Lead Temperature, soldering 10 sec ..........................300ºC
Supply Input Voltage (VSUPPLY) .....................................+10V
Control Voltage (VCTL) ................................... –0.6V to +16V Package Thermal Resistance
Gate Voltage (VG).........................................................+16V SOT-143 (θJA) ....................................................220°C/W
SOT-143 (θJC) ....................................................130°C/W
Ambient Temperature Range (TA)...............–40°C to +85°C

Electrical Characteristics
Parameter Conditions(1) Min Typ Max Units
Supply Current VSUPPLY = 3.3V VCTL = 0V 0.01 1 µA
VCTL = 3.3V 70 140 µA
VSUPPLY = 5V VCTL = 0V 0 1 µA
VCTL = 5V 150 300 µA
Control Input Voltage 2.7V ≤ VSUPPLY ≤ 9V VCTL for logic 0 input 0 0.8 V
2.7V ≤ VSUPPLY ≤ 5V VCTL for logic 1 input 2.0 VSUPPLY V
5V ≤ VSUPPLY ≤ 9V VCTL for logic 1 input 2.4 VSUPPLY V
Control Input Current 2.7V ≤ VSUPPLY ≤ 9V 0.01 1 µA
(2)
Control Input Capacitance 5 pF
Zener Diode Output Clamp VSUPPLY = 9V 13 16 19 V
Gate Output Voltage VSUPPLY = 2.7V 6.3 7.1 V
VSUPPLY = 3.0V 7.1 8.2 V
VSUPPLY = 4.5V 11.4 13.4 V
(3)
Gate Output Current VSUPPLY = 5V VOUT = 10V 9.5 µA
(4)
Gate Turn-On Time VSUPPLY = 4.5V CL = 1000pF 0.75 1.5 Ms
(4)
CL = 3000pF 2.1 4.2 ms
(5)
Gate Turn-Off Time VSUPPLY = 4.5V CL = 1000pF 10 20 µs
(5)
CL = 3000pF 30 60 µs
Notes:
General Note: Devices are ESD protected, however handling precautions are recommended.
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.
2. Guaranteed by design.
3. Resistive load selected for VOUT = 10V.
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.
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.

Test Circuit
VS U P P L Y

0.1µF MIC5018
2 3
VS G VOU T
4
C T L GND
1 CL
5V
0V

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Typical Characteristics(4)

Supply Current
vs. Supply Voltage
1.0

0.8
-40°C
0.6
25°C
0.4

0.2 125°C

0
0 2 4 6 8 10
SUPPLY VOLTAGE (V)

Gate Output Voltage

vs. Supply Voltage
20
125°C

15
-40°C 25°C
10

0
0 2 4 6 8 10
SUPPLY VOLTAGE (V)

Note 4: TA = 25°C, VSUPPLY = 5V unless noted.

Note 5: Full turn-on time is the time between V CTL rising to 2.5V and the VG rising to 90% of its steady on-state value.
Note 6: Full turn-off time is the time between V CTL falling to 0.5V and the VG falling to 10% of its steady on-state value.

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Functional Diagram
+2.7V to +9V

VS MIC5018
I1
20µA
D2
35V
Q1

On CTL R1 2k G
Off Q2 EN CHARGE
PUMP
D1 D3 16V
R2
16V Q3
15k
GND

Load
Functional Diagram with External Components
(High-Side Driver Configuration)

Functional Description approximately:

VG = 4 × VSUPPLY – 2.8V, but not exceeding 16V
Refer to the functional diagram.
The oscillator operates from approximately 70kHz to
The MIC5018 is a noninverting device. Applying a logic
approximately 100kHz depending upon the supply
high signal to CTL (control input) produces gate drive
voltage and temperature.
output. The G (gate) output is used to turn on an
external N-channel MOSFET. Gate Output
Supply The charge pump output is connected directly to the G
(gate) output. The charge pump is active only when CTL
VS (supply) is rated for +2.7V to +9V. An external
is high. When CTL is low, Q3 is turned on by the second
capacitor is recommended to decouple noise.
inverter and discharges the gate of the external
Control MOSFET to force it off.
CTL (control) is a TTL compatible input. CTL must be If CTL is high, and the voltage applied to VS drops to
forced high or low by an external signal. A floating input zero, the gate output will be floating (unpredictable).
may cause unpredictable operation.
ESD Protection
A high input turns on Q2, which sinks the output of
D1 and D2 clamp positive and negative ESD voltages.
current source I1, making the input of the first inverter
R1 isolates the gate of Q2 from sudden changes on the
low. The inverter output becomes high enabling the
CTL input. Q1 turns on if the emitter (CTL input) is
charge pump.
forced below ground to provide additional input
Charge Pump protection. Zener D3 also clamps ESD voltages for the
gate (G) output.
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

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Application Information Standard MOSFET

Standard MOSFETs are fully enhanced with a gate-to-
Supply Bypass source voltage of about 10V. Their absolute maximum
A capacitor from VS to GND is recommended to control gate-to-source voltage is ±20V.
switching and supply transients. Load current and supply With a 5V supply, the MIC5018 produces a gate output
lead length are some of the factors that affect capacitor of approximately 15V. Figure 2 shows how the remaining
size requirements. voltages conform. The actual drain-to-source voltage
A 4.7µF or 10µF aluminum electrolytic or tantalum drop across an IRFZ24 is less than 0.1V with a 1A load
capacitor is suitable for many applications. and 10V enhancement. Higher current increases the
drain-to-source voltage drop, increasing the gate-to-
The low ESR (equivalent series resistance) of tantalum
source voltage.
capacitors makes them especially effective, but also
+5V
makes them susceptible to uncontrolled inrush current
from low impedance voltage sources (such as NiCd
batteries or automatic test equipment). Avoid
4.7µF MIC5018
instantaneously applying voltage, capable of high peak 2 3 15V
VS G IRFZ24* approx. 0V
current, directly to or near tantalum capacitors without
4 1
additional current limiting. Normal power supply turn-on Logic C T L GND 10V
(slow rise time) or printed circuit trace resistance is High
To demonstrate

Load
usually adequate for normal product usage. Voltages are approximate
5V
this circuit, trya
2 , 20W
* International Rectifier load resistor.
standard MOSFET
MOSFET Selection
The MIC5018 is designed to drive N-channel
Figure 2. Using a Standard MOSFET
enhancement type MOSFETs. The gate output (G) of
the MIC5018 provides a voltage, referenced to ground,
that is greater than the supply voltage. Refer to the The MIC5018 has an internal zener diode that limits the
“Typical Characteristics: Gate Output Voltage vs. Supply gate-to-ground voltage to approximately 16V.
Voltage” graph. Lower supply voltages, such as 3.3V, produce lower
The supply voltage and the MOSFET drain-to-source gate output voltages which will not fully enhance
voltage drop determine the gate-to-source voltage. standard MOSFETs. This significantly reduces the
VGS = VG – (VSUPPLY – VDS) maximum current that can be switched. Always refer to
the MOSFET data sheet to predict the MOSFET’s
where:
performance in specific applications.
VGS = gate-to-source voltage (enhancement)
VG = gate voltage (from graph) Logic-Level MOSFET
VSUPPLY = supply voltage Logic-level N-channel MOSFETs are fully enhanced with
a gate-to-source voltage of approximately 5V and
VDS = drain-to-source voltage
generally have an absolute maximum gate-to-source
(approx. 0V at low current, or when fully enhanced)
voltage of ±10V.
VS U P P L Y
+3.3V

MIC5018 D
2 3 VG G 4.7µF MIC5018
VS G VD S 2 3 9V
S
VS G IRLZ44* approx. 0V
4 1
C T L GND VG S 4 1
Logic C T L GND 5.7V
High
Load

To demonstrate
Load

this circuit, try

VLOAD Voltages are approximate 5 , 5W or
3.3V 47 , 1/4W
* International Rectifier load resistors.
logic-level MOSFET

Figure 1. Voltages
Figure 3. Using a Logic-Level MOSFET

The performance of the MOSFET is determined by the Refer to Figure 3 for an example showing nominal
gate-to-source voltage. Choose the type of MOSFET voltages. The maximum gate-to-source voltage rating of
according to the calculated gate-to-source voltage. a logic-level MOSFET can be exceeded if a higher

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supply voltage is used. An external zener diode can Split Power Supply
clamp the gate-to-source voltage as shown in Figure 4. Refer to Figure 6. The MIC5018 can be used to control a
The zener voltage, plus its tolerance, must not exceed 12V load by separating the driver supply from the load
the absolute maximum gate voltage of the MOSFET. supply.
VS U P P L Y +5V +12V

4.7µF MIC5018
2 3 15V
MIC5018 Logic-leve VS G IRLZ44* approx. 0V
2 3
VS G N-channel 4 1
Logic C T L GND 3V
4 1
MO S F E T
C T L GND High To demonstrate

Load
this circuit, trya
Voltages are approximate 40 , 5W or
12V 100 , 2W
5V <VZ < 10V * International Rectifier
Load logic-level MOSFET
load resistor.
Protects gate of
logic-level MOSFET
Figure 6. 12V High-Side Switch
Figure 4. Gate-to-Source Protection
A logic-level MOSFET is required. The MOSFET’s
maximum current is limited slightly because the gate is
A gate-to-source zener may also be required when the not fully enhanced. To predict the MOSFETs
maximum gate-to-source voltage could be exceeded due performance for any pair of supply voltages, calculate
to normal part-to-part variation in gate output voltage. the gate-to-source voltage and refer to the MOSFET
Other conditions can momentarily increase the gate-to- data sheet.
source voltage, such as turning on a capacitive load or
shorting a load. VGS = VG – (VLOAD SUPPLY – VDS)
VG is determined from the driver supply voltage using the
Inductive Loads “Typical Characteristics: Gate Output Voltage vs. Supply
Inductive loads include relays, and solenoids. Long Voltage” graph.
leads may also have enough inductance to cause
adverse effects in some circuits. Low-Side Switch Configuration
+2.7V to +9V The low-side configuration makes it possible to switch a
voltage much higher than the MIC5018’s maximum
supply voltage.
4.7µF MIC5018 +80V
2 3
VS G * International Rectifier
standard MOSFET
4 1 B VD SS = 100V To demonstrate
C T L GND

Load
this circuit, try
On 1k, 10W or
Off 33k, 1/4W
+2.7 to +9V load resistors.
Schottky
Diode MIC5018
4.7µF 2 3
IRF540*
VS G N-channel
4 1 MO S F E T
C T L GND
On
Figure 5. Switching an Inductive Load Off

Figure 7. Low-Side Switch Configuration

Switching off an inductive load in a high-side application
momentarily forces the MOSFET source negative (as The maximum switched voltage is limited only by the
the inductor opposes changes to current). This voltage MOSFET’s maximum drain-to-source ratings.
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.

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Package Information

SOT-143 (M4)

MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com

The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its
use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.

Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product
can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant
into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A
Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully
indemnify Micrel for any damages resulting from such use or sale.

© 1997 Micrel, Incorporated.

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