The MAX15054 is a high-side, n-channel MOSFET driver
for high-voltage applications capable of switching at high
frequencies. This device is controlled by a CMOS logiclevel signal referenced to ground and features a very
short (12ns, typ) propagation delay from input to output.
The high-voltage operation and high source/sink-current
capability make the MAX15054 ideal for HB LED drivers
and DC-DC converters.
The MAX15054 is well suited to complement other Maxim
LED driver products such as the MAX16814, MAX16838,
MAX16833, MAX16834, and MAX16826. The MAX15054
adds a high-side driver to those products that include only a
low-side driver; it then allows for buck-boost configurations
for multistring drivers similar to the MAX16814, MAX16838,
and MAX16826, and for buck-boost conversion with output
referenced to ground for single-string drivers such as the
MAX16834 and MAX16833.
The MAX15054 is available in the industry-standard 6-pin
SOT23 package and operates over the -40NC to +125NC
automotive temperature range.
and DC-DC Applications
Features
Input Voltage on High-Side n-Channel MOSFET Up
S
to 60V
S Up to 13.5V Logic Input Independent of Supply
Voltage
S 2A Peak Source and Sink Current
S 12ns Propagation Delay
S Rise and Fall Times of 6ns while Driving 1000pF
Capacitance
S Low Input Capacitance
S Low-Side and High-Side Undervoltage Protection
S Allows Buck-Boost Topology Referred to Ground
for LED Drivers and DC-DC Converters
S Allows Buck-Boost Topology for Multistring LED
Drivers
S 6-Pin SOT23 Package
Ordering Information
MAX15054
Applications
HB LED Drivers for Single and Multiple Strings
LED Backlight Drivers
High-Side Driver for DC-DC Converters
(Buck, Buck-Boost, Half-Bridge, Full-Bridge)
PARTTEMP RANGE
MAX15054AUT+
-40NC to +125NC
PIN-
PACKAGE
6 SOT23ACOM
+Denotes a lead(Pb)-free/RoHS-compliant package.
Pin Configuration appears at end of data sheet.
TOP
MARK
Typical Operating Circuits
V
IN
V
DD
C
1
GND
C
2
R
1
R
2
INGATE NDRV
EN
V
CC
C
3
R
3
V
DRV
C
4
DIM
COMP
R
4
SGNDPGND
C
4
CFB
D
1
MAX15054
MAX16838
HI
LEDGND
HDRV
DRAIN
OUT1
OUT2
BST
C
BST
Q1
LX
OV
R
7
ISET
FLT
CS
RT
R
6
D
3
L1
C
D
2
R
5
5
R
8
R
9
Typical Operating Circuits continued at end of data sheet.
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-
layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
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
(VDD = V
unless otherwise noted.) (Note 2)
Operating Supply VoltageV
VDD Quiescent Supply CurrentI
BST Quiescent Supply CurrentI
BST Operating Supply Current I
High-Side MOSFET Driver for HB LED Drivers
and DC-DC Applications
Pin Description
PINNAMEFUNCTION
1HI
2GNDGround
3V
MAX15054
4BST
5HDRVHigh-Side Gate-Driver Output. Driver output to drive the high-side external MOSFET gate.
6LXSource Connection for High-Side MOSFET. LX also serves as a return terminal for the high-side driver.
DD
Functional Diagram
5V CMOS Logic Input. HI is referenced to GND and is capable of withstanding voltages up to 13.5V for
any VDD voltage.
Input Supply Voltage. Valid supply voltage ranges from 4.6V to 5.5V. Bypass VDD to GND with a 0.1FF
ceramic capacitor as close as possible to the device.
Boost Flying Capacitor Connection. Connect a minimum of a 0.1FF ceramic capacitor between BST
and LX for the high-side MOSFET driver supply. Connect a bootstrap Schottky diode between VDD
and BST.
BST
HIGH-SIDE
UVLO
EXTERNAL
GND
D
1
MAX15054
V
DD
LOW-SIDE
UVLO
HI
Detailed Description
The MAX15054 n-channel MOSFET driver controls an
external high-side MOSFET in high-voltage, high-current
applications. This driver operates with a supply voltage of
4.6V to 5.5V, and consumes only 300FA of supply current
during typical switching operations (fSW = 500kHz) and
no-load conditions. The MAX15054 provides 2.5A (typ)
sink/source peak current and is capable of operating with
large capacitive loads and with switching frequencies
up to 2MHz. The device is used to drive the high-side
MOSFET without requiring an isolation device such as an
optocoupler or a drive transformer.
HDRV
LX
LEVEL
SHIFT UP
LEVEL SHIFT
DOWN
The high-side driver is controlled by a CMOS logic
referenced to ground and is powered by a bootstrap
circuit formed by an external diode and capacitor.
Undervoltage lockout (UVLO) protection is provided for
both the high- and low-side driver supplies (BST and
VDD) and includes a UVLO hysteresis of 0.2V (typ).
The MAX15054’s fast switching times and very short
propagation delays (11ns, typ) are ideal for highfrequency applications. Internal logic circuitry prevents
shoot-through during output state changes and minimizes
package power dissipation.
The MAX15054 drives an external high-side MOSFET.
Both the high- and low-side supplies feature separate
UVLO protection that monitors each driver’s input supply
voltage (BST-LX and VDD). The low-side supply UVLO
threshold (V
the driver output low when VDD falls below 4V (typ)
irrespective of the high-side UVLO condition.
The high-side driver UVLO threshold (V
referenced to LX, and pulls HDRV low when V
below 3.6V (typ) with respect to LX. After the MAX15054 is
first energized (VDD > V
(C
BST
does not switch since the BST-to-LX voltage is below
V
BST_UVLO
BST-LX supply through an external Schottky diode and
within a short time C
V
to exceed V
BST
and follows HI. The hysteresis is 0.2V (typ) for both UVLO
thresholds.
The MAX15054 driver contains low on-resistance
p-channel and n-channel devices in a totem pole
configuration for the driver output stage. This allows for
rapid turn-on and turn-off of high gate-charge (Qg)
external switching MOSFETs. The driver exhibits low
drain-to-source resistance (R
lower operating temperatures. Lower R
higher source and sink currents from the device as
the external MOSFET gate capacitance charges and
discharges at a quicker rate, resulting in faster switching
speeds. The peak source and sink current provided by
the driver is 2.5A (typ).
Propagation delay from the logic input (HI) to the driver
output is 12ns (typ) (Figure 1). The internal driver also
contains break-before-make logic to eliminate shootthrough conditions that cause unnecessarily high
operating supply currents, efficiency reduction, and
voltage spikes at VDD.
Voltage from HDRV to LX is approximately equal to VDD
minus the diode drop of the bootstrap diode when in a
high state, and zero when in a low state.
DD_UVLO
) between BST and LX is not charged, and HDRV
. An internal charging circuit charges the
) is referenced to GND and pulls
BST_UVLO
DD_UVLO
charges through VDD and causes
BST
BST_UVLO
), the bootstrap capacitor
. HDRV then starts switching
Output Driver
) that decreases for
DS(ON)
DS(ON)
) is
falls
BST
means
and DC-DC Applications
Bootstrap Diode
Connect an external Schottky diode between VDD and
BST, in conjunction with an external bootstrap capacitor
(C
), to provide the voltage required to turn on the
BST
MOSFET (see the Typical Operating Circuits). The diode
charges the bootstrap capacitor from V
high-side switch is off, and isolates VDD when HDRV is
pulled high when the driver turns on.
Bootstrap Capacitor
The bootstrap capacitor (C
used to ensure adequate charge is available to switch
the high-side MOSFET. This capacitor is charged from
VDD by an external bootstrap diode when the MOSFET
is off. The bootstrap capacitor value should be selected
carefully to avoid oscillations during turn-on and turnoff at the HDRV output. Choose a capacitor value at
least 20 times greater than the total gate capacitance
of the MOSFET being switched. Use a low-ESR ceramic
capacitor (typically a minimum 0.1FF is needed). The
high-side MOSFET’s continuous on-time is limited due
to the charge loss from the high-side driver’s quiescent
current. The maximum on-time is dependent on the size
of C
BST
, I
(125FA, max), and V
BST
) between BST and LX is
BST
BST_UVLO
Driver Logic Input (HI)
The MAX15054 features a 5V CMOS logic input. The
required logic-input levels are independent of VDD and
are capable of withstanding up to 13.5V. For example,
the MAX15054 can be powered by a 5V supply while the
logic inputs are provided from 12V logic. Additionally, HI
is protected against voltage spikes up to 15V, regardless
of the VDD voltage. The logic input has 900mV hysteresis
to avoid double pulsing during signal transition. The logic
input is a high-impedance input (300kI, typ) and should
not be left unconnected to ensure the input logic state is
at a known level. With the logic input unconnected, HDRV
pulls low as VDD rises above the UVLO threshold. The
PWM output from the controller must assume a proper
state while powering up the device.
For the latest package outline information and land patterns, go
to www.maxim-ic.com/packages.
PACKAGE TYPEPACKAGE CODEDOCUMENT NO.
6 SOT23U6+1
21-0058
MAX15054
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.
Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 9