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MIC5018
IttyBittyTM High-Side MOSFET Driver
General Description
The MIC5018 IttyBittyTM 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 -40C to +85C ambient temperature range.
Features
* * * * * * * * +2.7V to +9V operation 150A typical supply current at 5V supply 1A 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
Typical Applications
+5V
VL O AD SU PPL Y Load voltage limited only by MOSFET drain-to-source rating
2 4
VS
G
3 1
Load
On Off
C T L GND
+2.7 to +9V 4.7F MIC5018
2 4 On Off
Load
3 1
4.7F
MIC5018
IRFZ24* N-Channel MO S F E T
* Siliconix 30m , 7A max., 30V VDS max. 8-lead SOIC package
* International Rectifier 100m , 17A max. TO-220 package
VS
G
C T L GND
Si9410DY* N-channel MO S F E T
Low-Voltage High-Side Power Switch
IttyBitty is a trademark of Micrel, Inc.
Low-Side Power Switch
Micrel Inc. * 2180 Fortune Drive * San Jose, CA 95131 * USA * tel +1 (408) 944-0800 * fax + 1 (408) 474-1000 * http://www.micrel.com
April 2006
M9999-042406 (408) 955-1690
Micrel, Inc.
MIC5018
Ordering Information
Part Number Standard MIC5018BM4 Pb-Free MIC5018YM4 H10 Making Standard Pb-Free H10 -40C to +85C SOT-143 Temp. Range Package
Pin Configuration
VS
2
GND
1
Part Identificatio n Early production identification: MH10
3
H10 H10
4
G CTL SOT-143 (M4)
Pin Description
Pin Number
1 2 3 4
Pin Name
GND VS G CTL
Pin Function
Ground: Power return. Supply (Input): +2.7V to +9V supply. Gate (Output): Gate connection to external MOSFET. Control (Input): TTL compatible on/off control input. Logic high drives the gate output above the supply voltage. Logic low forces the gate output near ground.
April 2006
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M9999-042406 (408) 955-1690
Micrel, Inc.
MIC5018
Absolute Maximum Ratings
Supply Input Voltage (VSUPPLY) .....................................+10V Control Voltage (VCTL) ................................... -0.6V to +16V Gate Voltage (VG).........................................................+16V Ambient Temperature Range (TA)...............-40C to +85C
Operating Ratings
Lead Temperature, soldering 10 sec ..........................300C Package Thermal Resistance SOT-143 (JA) ....................................................220C/W SOT-143 (JC) ....................................................130C/W
Electrical Characteristics
Parameter
Supply Current
Conditions(1)
VSUPPLY = 3.3V VSUPPLY = 5V VCTL = 0V VCTL = 3.3V VCTL = 0V VCTL = 5V VCTL for logic 0 input VCTL for logic 1 input VCTL for logic 1 input
Min
Typ
0.01 70 0 150
Max
1 140 1 300 0.8 VSUPPLY VSUPPLY
Units
A A A A V V V A pF V V V V A
Control Input Voltage
2.7V VSUPPLY 9V 2.7V VSUPPLY 5V 5V VSUPPLY 9V
0 2.0 2.4 0.01 5 13 6.3 7.1 11.4 16 7.1 8.2 13.4 9.5 0.75 2.1 10 30
Control Input Current Control Input Capacitance Zener Diode Output Clamp Gate Output Voltage
2.7V VSUPPLY 9V
(2)
1 19
VSUPPLY = 9V VSUPPLY = 2.7V VSUPPLY = 3.0V VSUPPLY = 4.5V
Gate Output Current Gate Turn-On Time Gate Turn-Off Time
Notes:
VSUPPLY = 5V VSUPPLY = 4.5V VSUPPLY = 4.5V
VOUT = 10V
(3) (4)
CL = 1000pF (4) CL = 3000pF CL = 1000pF (5) CL = 3000pF
1.5 4.2 20 60
Ms ms s s
(5)
General Note: Devices are ESD protected, however handling precautions are recommended. 1. Typical values at TA = 25C. Minimum and maximum values indicate performance at -40C TA +85C. Parts production tested at 25C. 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 0.1F
2 4 5V 0V
MIC5018 VS G
3 1
VOU T CL
C T L GND
April 2006
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M9999-042406 (408) 955-1690
Micrel, Inc.
MIC5018
Typical Characteristics(4)
Supply Current vs. Supply Voltage
1.0 0.8
-40C 0.6 25C 0.4 0.2 0 125C 0 2 4 6 8 10 SUPPLY VOLTAGE (V)
20 15
Gate Output Voltage vs. Supply Voltage
125C
-40C 10 5 0
25C
0
2 4 6 8 10 SUPPLY VOLTAGE (V)
Note 4: Note 5: Note 6:
TA = 25C, VSUPPLY = 5V unless noted. 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. 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.
April 2006
4
M9999-042406 (408) 955-1690
Micrel, Inc.
MIC5018
Functional Diagram
+2.7V to +9V
VS I1 20A
MIC5018 D2 35V Q1
On Off
CTL
R1 2k D1 16V
Q2 R2 15k
EN CHARGE PUMP
G D3 16V Q3
Functional Diagram with External Components (High-Side Driver Configuration)
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 (4x). Output voltage is limited to 16V by a zener diode. The charge pump output voltage will be
approximately: VG = 4 x VSUPPLY - 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.
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5
Load
M9999-042406 (408) 955-1690
GND
Micrel, Inc.
MIC5018 Standard MOSFET Standard MOSFETs are fully enhanced with a gate-tosource voltage of about 10V. Their absolute maximum gate-to-source 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 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-tosource voltage.
+5V
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 4.7F or 10F 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 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 "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 - (VSUPPLY - VDS) where: VGS = gate-to-source voltage (enhancement) VG = gate voltage (from graph) VSUPPLY = supply voltage VDS = drain-to-source voltage (approx. 0V at low current, or when fully enhanced)
VS U P P L Y
4.7F Logic High
MIC5018
2 4
VS
G
3 15V 1
IRFZ24* approx. 0V
C T L GND
10V
To demonstrate this circuit, try a 2 , 20W load resistor .
Voltages are approximate * International Rectifier standard MOSFET
5V
Figure 2. Using a Standard MOSFET
The MIC5018 has an internal zener diode that limits the gate-to-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
MIC5018
2 4
VS
G
3 1
VG
G
D S
VD S
4.7F Logic High
MIC5018
2 4
VS
G
3 1
9V 5.7V
C T L GND
VG S VLOAD
C T L GND
Load
Load Load
IRLZ44* approx. 0V
Voltages are approximate * International Rectifier logic-level MOSFET
3.3V
To demonstrate this circuit, try 5 , 5W or 47 , 1/4W load resistors.
Figure 1. Voltages
Figure 3. Using a Logic-Level MOSFET
The performance of the MOSFET is determined by the gate-to-source voltage. Choose the type of MOSFET according to the calculated gate-to-source voltage. April 2006 6
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
M9999-042406 (408) 955-1690
Micrel, Inc. 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.
VS U P P L Y
MIC5018 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.
+5V 4.7F MIC5018
2 4 3 15V 1
+12V
MIC5018
2 4
VS
G
3 1
Voltages are approximate
5V Load
* International Rectifier logic-level MOSFET
12V
Figure 6. 12V High-Side Switch Figure 4. Gate-to-Source Protection
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-tosource 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
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 - (VLOAD 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 standard MOSFET B V SS = 100V D
4.7F
MIC5018
2 4
VS
G
3 1
Load
C T L GND
Logic-leve N-channel MO S F E T
VS
G
IRLZ44* approx. 0V
Logic High
C T L GND
3V
To demonstrate this circuit, try a 40 , 5W or 100 , 2W load resistor.
On Off
Schottky Diode
+2.7 to +9V 4.7F MIC5018
2 4
Load G
3 1
C T L GND
To demonstrate this circuit, try 1k, 10W or 33k, 1/4W load resistors.
VS
Figure 5. Switching an Inductive Load
On Off
C T L GND
IRF540* N-channel MO S F E T
Figure 7. Low-Side Switch Configuration
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. April 2006 7
The maximum switched voltage is limited only by the MOSFET's maximum drain-to-source ratings.
M9999-042406 (408) 955-1690
Micrel, Inc.
MIC5018
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. (c) 1997 Micrel, Incorporated.
April 2006
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M9999-042406 (408) 955-1690

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