IC CTRLR PWM STP-DN TRIPL 32WQFN

MAX15048ETJ+

Manufacturer Part NumberMAX15048ETJ+
DescriptionIC CTRLR PWM STP-DN TRIPL 32WQFN
ManufacturerMaxim Integrated Products
MAX15048ETJ+ datasheet
 


Specifications of MAX15048ETJ+

ApplicationsPower Supply Controller, SequencerVoltage - Supply4.7 V ~ 23 V
Current - Supply6mAOperating Temperature-40°C ~ 85°C
Mounting TypeSurface MountPackage / Case32-WQFN Exposed Pad
Number Of Outputs3Output Voltage5 V
Input Voltage4.7 V to 23 VSupply Current6 mA
Switching Frequency200 KHzMounting StyleSMD/SMT
Maximum Operating Temperature+ 85 CMinimum Operating Temperature- 40 C
Lead Free Status / RoHS StatusLead free / RoHS CompliantVoltage - Input-
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MOSFET Gate Drivers and
Internal Boost Switch
DREG_ is the supply input for the low-side MOSFET
driver. Connect DREG_ to REG externally. Every time
the low-side MOSFET switches on, high peak current
is drawn from DREG_ for a short time. Adding an RC
filter (1I to 4.7I and 220nF ceramic capacitors are
typical) from REG to DREG_ filters out these high-peak
currents. Alternatively, DREG_ can be connected to an
). Note that the DREG_ volt-
external source (V
DREG-EXT
age should be high enough to fully enhance the low-side
MOSFET. To avoid partial enhancing of the MOSFETs,
use V
to set the UVLO externally using EN1.
DREG-EXT
BST_ supplies the power for the high-side MOSFET drivers.
The MAX15048/MAX15049 consist of an internal switch
between DREG_ and BST_ to boost DH_ voltage above
V
, providing the necessary gate-to-source voltage to
IN
turn on the high-side MOSFET. Connect a bootstrap
0.1FF or higher ceramic capacitor between BST_ and
LX_.
The high-side (DH_) and low-side (DL_) drivers drive the
gates of the external n-channel MOSFETs. The drivers’
1A peak source-and-sink-current capability provides
ample drive for the fast rise and fall times of the switch-
ing MOSFETs. Faster rise and fall times result in reduced
switching losses.
The gate-driver circuitry also provides a break-before-
make time (35ns typ) to prevent shoot-through currents
during transition.
MAX15048 Coincident/
Ratiometric Tracking (EN_)
The enable input (EN_) in conjunction with digital soft-
start and soft-stop provide coincident/ratiometric track-
ing. Track an output voltage by connecting a resistive
voltage-divider from the output being tracked to the
enable/tracking input. For example, for V
cidentally track V
, connect the same resistive
OUT1
voltage-divider used for FB2 from OUT1 to EN2
to SGND. See Figure 2 and the Typical Operating
Characteristics (Coincident Tracking).
Track ratiometrically by connecting EN_ to SGND. This
synchonizes the soft-start and soft-stop of all the control-
lers’ references, and hence their respective output volt-
ages track ratiometrically. See Figure 2 and the Typical
Operating Characteristics (Ratiometric Tracking).
For the MAX15048, the output short-circuit fault situa-
tions at master or slave outputs are handled carefully
______________________________________________________________________________________
Triple-Output Buck Controllers
with Tracking/Sequencing
so that either the master or slave output does not stay
on when the other outputs are shorted to ground. When
the slave is shorted and enters in hiccup mode, both
the master and the other slave soft-stop. When the
master is shorted and the part enters hiccup mode, the
slaves ratiometrically soft-stop. Coming out of the hic-
cup, all outputs soft-start coincidently or ratiometrically
depending on their initial configuration. See the Typical
Operating Characteristics for the output behavior dur-
ing the fault conditions. During the thermal shutdown or
power-off when the input falls below its UVLO, the output
voltages fall down at a rate depending on the respective
output capacitor and load.
See Figure 1 for a graphical representation of coinci-
dent/ratiometric tracking (MAX15048) or sequencing
(MAX15049).
to coin-
OUT2
SOFT-START
* THE FALLING EDGES OF THE MAX15049 DEPEND ON THE LOAD CURRENT.
Figure 1. Graphical Representation of Coincident Tracking,
Ratiometric Tracking (MAX15048), or Sequencing (MAX15049)
V
OUT1
V
OUT2
V
OUT3
SOFT-START
SOFT-STOP
a) COINCIDENT TRACKING OUTPUTS
V
OUT1
V
OUT2
V
OUT3
SOFT-START
SOFT-STOP
b) RATIOMETRIC TRACKING OUTPUTS
V
OUT1
V
OUT2
V
OUT3
c) SEQUENCED OUTPUTS*
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