MIC5014/5015
Micrel, Inc.
MIC5014/5015
Low-Cost High- or Low-Side MOSFET Driver
General Description
MIC5014 and MIC5015 MOSFET drivers are designed for
gate control of N-channel, enhancement-mode, power
MOSFETs used as high-side or low-side switches.
The MIC5014/5 can sustain an on-state output indefinitely.
The MIC5014/5 operates from a 2.75V to 30V supply. In high-
side configurations, the driver can control MOSFETs that
switch loads of up to 30V. In low-side configurations, with
separate supplies, the maximum switched voltage is limited
only by the MOSFET.
The MIC5014/5 has a TTL compatible control input.
The MIC5014 is noninverting while the MIC5015 is inverting.
The MIC5014/5 features an internal charge pump that can
sustain a gate voltage greater than the available supply
voltage. The driver is capable of turning on a logic-level
MOSFET from a 2.75V supply or a standard MOSFET from a
5V supply. The gate-to-source output voltage is internally
limited to approximately 15V.
The MIC5014/5 is protected against automotive load dump,
reversed battery, and inductive load spikes of –20V.
The driver’s overvoltage shutdown feature turns off the exter-
nal MOSFET at approximately 35V to protect the load against
power supply excursions.
The MIC5014 is an improved pin-for-pin compatible replace-
ment in many MIC5011 applications.
The MIC5014/5 is available in plastic 8-pin DIP and 8-pin
SOIC pacakges.
Features
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2.75V to 30V operation
100µA maximum supply current (5V supply)
15µA typical off-state current
Internal charge pump
TTL compatible input
Withstands 60V transient (load dump)
Reverse battery protected to –20V
Inductive spike protected to –20V
Overvoltage shutdown at 35V
Internal 15V gate protection
Minimum external parts
Operates in high-side or low-side configurations
1µA control input pull-off
Inverting and noninverting versions
Applications
•
•
•
•
•
•
Automotive electrical load control
Battery-powered computer power management
Lamp control
Heater control
Motor control
Power bus switching
Typical Application
+3V to +4V
10µF
MIC5014
1
Control Input
ON
OFF
V+
Input
Source
NC
NC
NC
8
7
6
IRLZ24
2
3
4 Gnd
Gate 5
Figure 1. 3V “Sleep-Mode” Switch
with a Logic-Level MOSFET
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2005
Load
1
MIC5014/5015
MIC5014/5015
Micrel, Inc.
Absolute Maximum Ratings
(Notes 1,2)
Supply Voltage ............................................... –20V to 60V
Input Voltage ..................................................... –20V to V
+
Source Voltage ..................................................–20V to V
+
Source Current .......................................................... 50mA
Gate Voltage .................................................. –20V to 50V
Junction Temperature .............................................. 150°C
Operating Ratings
(Notes 1,2)
θ
JA
(Plastic DIP) ..................................................... 160°C/W
θ
JA
(SOIC) ............................................................. 170°C/W
Ambient Temperature: ................................ –40°C to +85°C
Storage Temperature ................................ –65°C to +150°C
Lead Temperature ...................................................... 260°C
(max soldering time: 10 seconds)
Supply Voltage (V
+
) ......................................... 2.75V to 30V
Electrical Characteristics
(Note 3) T
A
= –40°C to +85°C
Parameter
Supply Current
V = 30V
V
+
= 5V
V
+
= 3V
Logic Input Voltage Threshold
V
IN
Logic Input Current
MIC5014 (non-inverting)
Logic Input Current
MIC5015 (inverting)
Input Capacitance
Gate Enhancement
V
GATE
– V
SUPPLY
Zener Clamp
V
GATE
– V
SOURCE
Gate Turn-on Time, t
ON
(Note 4)
3.0V
≤
V
+
≤
30V
T
A
= 25°C
3.0V
≤
V
+
≤
30V
3.0V
≤
V
+
≤
30V
+
3.0V
≤
V
≤
30V
8.0V
≤
V
+
≤
30V
V
+
= 4.5V
C
L
= 1000pF
V
+
= 12V
C
L
= 1000pF
V
+
= 4.5V
C
L
= 1000pF
V
+
= 12V
C
L
= 1000pF
+
unless otherwise specified
Conditions
Min
Typ
V
IN
De-Asserted (Note 5)
10
V
IN
Asserted (Note 5)
5.0
V
IN
De-Asserted
10
V
IN
Asserted
60
V
IN
De-Asserted
10
V
IN
Asserted
25
Digital Low Level
Digital High Level
2.0
V
IN
Low
–2.0
0
V
IN
High
1.0
V
IN
Low
–2.0
–1.0
V
IN
High
–1.0
5.0
V
IN
Asserted
4.0
V
IN
Asserted
13
15
2.5
90
6.0
6.0
35
37
Max
25
10
25
100
25
35
0.8
Units
µA
mA
µA
µA
V
µA
µA
pF
V
V
ms
µs
µs
µs
V
2.0
2.0
17
17
8.0
140
30
30
41
Gate Turn-off Time, t
OFF
(Note 4)
V
IN
switched on, measure
time for V
GATE
to reach V
+
+ 4V
As above, measure time for
V
GATE
to reach V
+
+ 4V
V
IN
switched off, measure
time for V
GATE
to reach 1V
As above, measure time for
V
GATE
to reach 1V
Overvoltage Shutdown
Threshold
Note 1: Absolute Maximum Ratings
indicate limits beyond which damage to the device may occur. Electrical specifications do not apply
when operating the device beyond its specified
Operating Ratings.
Note 2:
The MIC5014/5015 is ESD sensitive.
Note 3:
Minimum and maximum
Electrical Characteristics
are 100% tested at T
A
= 25°C and T
A
= 85°C, and 100% guaranteed over the
entire operating temperature range. Typicals are characterized at 25°C and represent the most likely parametric norm.
Note 4:
Test conditions reflect worst case high-side driver performance. Low-side and bootstrapped topologies are significantly faster—see
Applications Information.
Note 5:
“Asserted” refers to a logic high on the MIC5014 and a logic low on the MIC5015.
June 2005
3
MIC5014/5015
MIC5014/5015
Micrel, Inc.
not use a socket for the MOSFET. If the MOSFET is a TO-220
type package, make high current connections to the drain tab.
Wiring losses have a profound effect on high-current circuits.
A floating milliohmeter can identify connections that are con-
tributing excess drop under load.
Low Voltage Testing
As the MIC5014/MIC5015 have relatively high output imped-
ances, a normal oscilloscope probe will load the device. This
is especially pronounced at low voltage operation. It is recom-
mended that a FET probe or unity gain buffer be used for all
testing.
Applications Information
Functional Description
The MIC5014 is functionally and pin for pin compatible with
the MIC5011, except for the omission of the optional speed-
up capacitor pins, which are available on the MIC5011. The
MIC5015 is an inverting configuration of the MIC5014.
The internal functions of these devices are controlled via a
logic block (refer to block diagram) connected to the control
input (pin 2). When the input is off (low for the MIC5014, and
high for the MIC5015), all functions are turned off, and the
gate of the external power MOSFET is held low via two N-
channel switches. This results in a very low standby current;
15µA typical, which is necessary to power an internal bandgap.
When the input is driven to the “ON” state, the N-channel
switches are turned off, the charge pump is turned on, and the
P-channel switch between the charge pump and the gate
turns on, allowing the gate of the power FET to be charged.
The op amp and internal zener form an active regulator which
shuts off the charge pump when the gate voltage is high
enough. This is a feature not found on the MIC5011.
The charge pump incorporates a 100kHz oscillator and on-
chip pump capacitors capable of charging a 1,000pF load in
90µs typical. In addition to providing active regulation, the
internal 15V zener is included to prevent exceeding the V
GS
rating of the power MOSFET at high supply voltages.
The MIC5014/15 devices have been improved for greater
ruggedness and durability. All pins can withstand being
pulled 20V below ground without sustaining damage, and the
supply pin can withstand an overvoltage transient of 60V for
1s. An overvoltage shutdown has also been included, which
turns off the device when the supply exceeds 35V.
Circuit Topologies
The MIC5014 and MIC5015 are well suited for use with
standard power MOSFETs in both low and high side driver
configurations. In addition, the lowered supply voltage re-
quirements of these devices make them ideal for use with logic
level FETs in high side applications with a supply voltage of 3
to 4V. (If higher supply voltages [>4V] are used with logic level
FETs, an external zener clamp must be supplied to ensure
that the maximum V
GS
rating of the logic FET [10V] is not
exceeded.) In addition, a standard IGBT can be driven using
these devices.
Choice of one topology over another is usually based on
speed vs. safety. The fastest topology is the low side driver,
however, it is not usually considered as safe as high side
driving as it is easier to accidentally short a load to ground than
to V
CC.
The slowest, but safest topology is the high side
driver; with speed being inversely proportional to supply
voltage. It is the preferred topology for most military and
automotive applications. Speed can be improved consider-
ably by bootstrapping from the supply.
All topologies implemented using these devices are well
suited to driving inductive loads, as either the gate or the
source pin can be pulled 20V below ground with no effect.
External clamp diodes are unnecessary, except for the case
in which a transient may exceed the overvoltage trip point.
High Side Driver
(Figure 1) The high side topology shown
here is an implementation of a “sleep-mode” switch for a
laptop or notebook computer which uses a logic level FET. A
standard power FET can easily be substituted when supply
voltages above 4V are required.
+3V to +30V
Construction Hints
High current pulse circuits demand equipment and assembly
techniques that are more stringent than normal, low current
lab practices. The following are the sources of pitfalls most
often encountered during prototyping:
Supplies
: Many bench
power supplies have poor transient response. Circuits that
are being pulse tested, or those that operate by pulse-width
modulation will produce strange results when used with a
supply that has poor ripple rejection, or a peaked transient
response. Always monitor the power supply voltage that
appears at the drain of a high side driver (or the supply side
of the load for a low side driver) with an oscilloscope. It is not
uncommon to find bench power supplies in the 1kW class that
overshoot or undershoot by as much as 50% when pulse
loaded. Not only will the load current and voltage measure-
ments be affected, but it is possible to overstress various
components, especially electrolytic capacitors, with possibly
catastrophic results. A 10µF supply bypass capacitor
at the
chip is
recommended.
Residual resistances:
Resistances
in circuit connections may also cause confusing results. For
example, a circuit may employ a 50mΩ power MOSFET for
low voltage drop, but unless careful construction techniques
are used, one could easily add 50 to 100mΩ resistance. Do
10µF
MIC5014
V+
Input
Source
NC
NC
NC
Control Input
ON
OFF
2
3
7
6
4 Gnd
Gate 5
Figure 2. Low Side Driver
June 2005
5
Load
1
8
MIC5014/5015
嵌入式系统
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