19-1176; Rev 1; 6/11
High-Side, n-Channel MOSFET
Switch Driver
_______________General Description
The MAX1614 drives high-side, n-channel power MOSFETs
to provide battery power-switching functions in portable
equipment. The n-channel power MOSFETs typically have
one-third the on-resistance of p-channel MOSFETs of simi-
lar size and cost. An internal micropower regulator and
charge pump generate the high-side drive output voltage,
while requiring no external components.
The MAX1614 also features a 1.5%-accurate low-battery
comparator that can be used to indicate a low-battery
condition, provide an early power-fail warning to the sys-
tem microprocessor, or disconnect the battery from the
load, preventing deep discharge and battery damage. An
internal latch allows for pushbutton on/off control with very
low current consumption. Off-mode current consumption
is only 6µA while normal operation requires less than
25µA. The MAX1614 is available in the space-saving
µMAX
®
package that occupies about 60% less space
than a standard 8-pin SO.
____________________________Features
o
Internal On/Off Latch
o
High-Side, n-Channel Power MOSFET Drive
o
25µA (max) Quiescent Current
o
6µA (max) Off Current
o
Requires No External Components
o
1.5%-Accurate Low-Battery Detector
o
Space-Saving
µMAX
Package
o
5V to 26V Input Voltage Range
o
Drives Single or Back-to-Back MOSFETs
o
Controlled Turn-On for Low Inrush Current
MAX1614
______________Ordering Information
PART
MAX1614C/D
MAX1614EUA+
MAX1614EUA/V+
TEMP RANGE
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
Dice*
8 µMAX
8 µMAX
________________________Applications
Notebook Computers
Portable Equipment
Hand-Held Instruments
Battery Packs
µMAX is a registered trademark of Maxim Integrated Products, Inc.
*Contact
factory for dice specifications.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
/V denotes an automotive qualified part.
Devices are also available in a tape-and-reel package.
Specify tape-and-reel by adding “T” to the part number when
ordering.
__________Typical Operating Circuit
N
N
LOAD
OPTIONAL FOR
REVERSE CURRENT
PROTECTION
GATE
SRC
ON
BATT
R1
LBI
R2
GND
LBO
__________________Pin Configuration
TOP VIEW
ON 1
OFF 2
LBO 3
LBI 4
+
8
BATT
SRC
GATE
GND
MAX1614
7
6
5
MAX1614
OFF
µMAX
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
High-Side, n-Channel MOSFET
Switch Driver
MAX1614
ABSOLUTE MAXIMUM RATINGS
BATT, SRC to GND.................................................-0.3V to +30V
GATE to SRC ..........................................................-0.3V to +12V
GATE to GND .........................................................-0.3V to +36V
GATE + SRC Sink Current, Continuous .............................2.7mA
LBI,
LBO, ON, OFF
to GND....................................-0.3V to +12V
LBO
Current ..........................................................................5mA
Continuous Power Dissipation (T
A
= +70°C)
µMAX (derate 4.10mV/°C above +70°C) .....................330mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
BATT
= 15V,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
BATT Operating Range
BATT Shutdown Current
I
SHDN
SYMBOL
CONDITIONS
V
GATE
- V
SRC
> 3V, SRC = BATT
V
BATT
= 26V,
ON
=
OFF
= unconnected,
I
GATE
= 0A, device latched off, V
LBI
= 1.5V
V
BATT
= 15V,
ON
=
OFF
= unconnected,
I
GATE
= 0A, device latched on, V
LBI
= 1.5V,
SRC = BATT
V
BATT
= 26V,
ON
=
OFF
= unconnected,
I
GATE
= 0A, device latched on, V
LBI
= 1.5V,
SRC = BATT
MIN
5
4
TYP
MAX
26
7
UNITS
V
µA
17
30
µA
µA
Quiescent Current
I
BATT
+
I
SRC
21
40
INTERNAL CHARGE PUMP
Measured from GATE to SRC, V
BATT
= 15V,
I
GATE
= 0A
Measured from GATE to SRC, V
BATT
= V
SRC
= 5V,
I
GATE
= 1.5µA
V
GATE
= V
SRC
= 15V
V
GATE
= 4V, device latched off
V
TH
LBI input falling
Tested at V
LBI
= V
BATT
/ 4
I
LBI
V
OL
V
OH
V
LBI
= 1.3V
I
SINK
= 1mA
V
LBO
= 11.5V
Tested at 2V
Tested at 0.6V
V
IL
V
IH
t
PW
V
BATT
= 5V
V
BATT
= 26V
V
BATT
= 5V
2.0
0.5
1.0
0.5
1.5
2
0.6
6.5
3
15
0.5
1.182
1.20
0.02V
TH
0.9
4
10
0.4
0.5
60
2
1.218
µA
mA
V
V
V
nA
V
µA
µA
µA
V
V
µs
8
9.0
V
GATE Drive Voltage
V
GS
GATE Drive Output Current
GATE Discharge Current
LOW-BATTERY COMPARATOR
LBI Trip Level
LBI Trip Hysteresis
Minimum V
BATT
for Valid
LBO
LBI Input Current
LBO
Low Voltage
LBO
High Leakage
O
CONTROL INPUTS (O
N
,
OFF
)
Minimum Input Pullup Current
Maximum Input Pullup Current
Input Low Voltage
Input High Voltage
Minimum Input Pulse Width
2
_______________________________________________________________________________________
High-Side, n-Channel MOSFET
Switch Driver
ELECTRICAL CHARACTERISTICS
(V
BATT
= 15V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
BATT Operating Range
BATT Shutdown Current
Quiescent Current
INTERNAL CHARGE PUMP
Measured from GATE to SRC, V
BATT
= 15V,
I
GATE
= 0A
Measured from GATE to SRC, V
BATT
= 5.25V,
I
GATE
= 1.5µA, V
SRC
= 5.25V
V
GATE
= V
SRC
= 15V
V
TH
LBI input falling
6.5
3
15
1.176
1.20
60
1.224
µA
V
9.0
V
I
SHDN
I
BATT
+
I
SAC
SYMBOL
CONDITIONS
V
GATE
- V
SRC
> 3V, SRC = BATT
V
BATT
= 26V,
ON
=
OFF
= unconnected,
I
GATE
= 0A, device latched off, V
LBI
= 1.5V
V
BATT
= 26V,
ON
=
OFF
= unconnected,
I
GATE
= 0A, device latched on, V
LBI
= 1.5V
MIN
5.0
TYP
MAX
26
8
40
UNITS
V
µA
µA
MAX1614
GATE Drive Voltage
V
GS
GATE Drive Output Current
LOW-BATTERY
LOW BATTERY COMPARATOR
LBI Trip Level
Note 1:
Specifications to T
A
= -40°C are guaranteed by design and not production tested.
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
ON SUPPLY CURRENT
vs. V
BATT
MAX1614-01
OFF SUPPLY CURRENT
vs. V
BATT
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
3.0
2.5
2.0
1.5
1.0
MAX1614-02
LOW-BATTERY THRESHOLD
vs. TEMPERATURE
V
BATT
= 15V
1.28
LBI THRESHOLD (V)
1.26
1.24
1.22
1.20
1.18
1.16
V
LBI
FALLING
MAX1614-05
22
20
SUPPLY CURRENT (µA)
18
16
14
12
10
8
6
5
10
15
20
25
T
A
= +25°C
T
A
= -40°C
T
A
= +85°C
4.0
3.5
SHUTDOWN CURRENT (µA)
1.30
V
LBI
RISING
30
5
10
15
20
25
30
-40
-20
0
20
40
60
80
100
VBATT (V)
VBATT (V)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
High-Side, n-Channel MOSFET
Switch Driver
MAX1614
____________________________Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
GATE-DISCHARGE CURRENT
vs. GATE VOLTAGE
MAX1614-04
GATE-CHARGING CURRENT
vs. TEMPERATURE
MAX1614--03
GATE-CHARGING CURRENT
vs. BATT VOLTAGE
29
28
27
T
A
= -40°C
26
25
24
23
22
MAX1614-06
2.5
T
A
= -40°C
GATE-DISCHARGE CURRENT (mA)
2.0
T
A
= +25°C
1.5
1.0
0.5
0
-0.5
0
2
4
6
8
T
A
= +85°C
34
GATE-CHARGING CURRENT (µA)
33
32
31
30
29
28
27
26
V
BATT
= 15V
30
GATE-CHARGING CURRENT (µA)
T
A
= +85°C
10 12 14 16 18 20
-40
-20
0
20
40
60
80
100
5
10
15
20
25
30
V
GATE
(V)
TEMPERATURE (°C)
V
BATT
(V)
GATE AND SOURCE TRANSITIONS
FOR TYPICAL MOSFET LOAD
MAX1614-07
GATE TURN-ON TRANSITION
FOR TYPICAL MOSFET LOAD
Si9936 MOSFETS
I
LOAD
= 1A
ON = GND
V
GATE
V
SRC
MAX1614-08
V
GATE
V
SRC
Si9936 MOSFETS
I
LOAD
= 1A
C
iss
= 400pF
ON = GND
5V/div
5V/div
0V
V
OFF
V
OFF
0V
1ms/div
100µs/div
GATE TURN-OFF TRANSITION
FOR TYPICAL MOSFET LOAD
MAX1614-09
V
GATE
Si9936 MOSFETS
I
LOAD
= 1A
C
iss
= 400pF
ON = GND
V
SRC
5V/div
V
OFF
20µs/div
4
_______________________________________________________________________________________
High-Side, n-Channel MOSFET
Switch Driver
MAX1614
______________________________________________________________Pin Description
PIN
1
2
3
4
5
6
7
8
NAME
ON
OFF
LBO
LBI
GND
GATE
SRC
BATT
FUNCTION
SET
Input to the On/Off Latch. Pulse
ON
low with
OFF
high to turn on the external MOSFET switch. When
both
ON
and
OFF
are low, the part is off.
RESET
Input to the On/Off Latch. Pulse
OFF
low with
ON
high to turn off the external MOSFET switch. When
both
ON
and
OFF
are low, the part is off.
Open-Drain, Low-Battery Comparator Output.
LBO
is low when V
LBI
is below the trip point.
Low-Battery Comparator Input.
LBO
goes low when V
LBI
falls below 1.20V (typ). Connect a voltage divider
between BATT, LBI, and GND to set the battery undervoltage trip threshold (see
Typical Operating Circuit).
System Ground
Gate-Drive Output. Connect to the gates of external, n-channel MOSFETs. When the MAX1614 is off, GATE
actively pulls to GND.
Source Input. Connect to the sources of external, n-channel MOSFETs. When the MAX1614 is off, SRC
actively pulls to GND.
Battery Input. Connect to a battery voltage between 5V and 26V.
_______________Detailed Description
The MAX1614 uses an internal, monolithic charge pump
and low-dropout linear regulator to supply the required
8V V
GS
voltage to fully enhance an n-channel MOSFET
high-side switch (Figure 1). The charge pump typically
supplies 30µA, charging 800pF of gate capacitance in
400µs (V
BATT
= 15V). For slower turn-on times, simply
add a small capacitor between the GATE and SRC
pins. When turned off, GATE and SRC pull low and typi-
cally discharge an 800pF gate capacitance in 80µs.
The MAX1614 provides separate on/off control inputs
(ON and
OFF). ON
and
OFF
connect, respectively, to
the
SET
and
RESET
inputs of an internal flip-flop. When
ON
is pulsed low (with
OFF
= high), the internal charge
pump turns on, and GATE is pumped to 8V above SRC,
turning on the external MOSFETs. The charge pump
maintains gate drive to the external MOSFETs until
OFF
is pulsed low. When this happens, the internal charge
pump turns off, and GATE discharges to ground
through an internal switch. For slower turn-on times,
simply add a small capacitor.
lower voltages (e.g., 3V or 5V) poses no problem if the
gate outputs driving these pins can sink at least 2µA
while high.
Although the MAX1614 shutdown function was designed
to operate with a single pushbutton on/off switch, it can
also be driven by a single gate. Connect
ON
to GND
and drive
OFF
directly (Figure 2).
Maximum Switching Rate
The MAX1614 is not intended for fast switching appli-
cations. In fact, it is specifically designed to limit the
rate of change of the load current,
∆I/∆t.
The maximum
switching rate is limited by the turn-on time, which is a
function of the charge-pump output current and the
total capacitance on GATE (C
GATE
). Calculate the turn-
on time as a function of external MOSFET gate capaci-
tance using the Gate Charging Current vs. V
BATT
graph
in the
Typical Operating Characteristics.
Since turn-off
time is small compared to turn-on time, the maximum
switching rate is approximately 1/t
ON
.
Adding Gate Capacitance
The charge pump uses an internal monolithic transfer
capacitor to charge the external MOSFET gates.
Normally, the external MOSFET’s gate capacitance is
sufficient to serve as a reservoir capacitor. If the
MOSFETs are located at a significant distance from the
MAX1614, place a local bypass capacitor (100pF typ)
across the GATE and SRC pins. For slower turn-on
times, simply add a small capacitor between GATE and
SRC.
__________ Applications Information
Connecting
ON
/
OFF
to 3V or 5V Logic
ON
and
OFF
internally connect to 2µA max pullup
current sources (Figure 1). The open-circuit voltage
for
ON
and
OFF
ranges from 7V to 10.5V (nominally
8.5V). Since the current sources are relatively weak,
connecting
ON
and
OFF
directly to logic powered from
_______________________________________________________________________________________
5
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