OMO ElectronicOMO Electronic
Expand menu
Hello, Sign inMy Account
0 Cart

MAX8546EUB+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18
General Description
The MAX8545/MAX8546/MAX8548 are voltage-mode
pulse-width-modulated (PWM), step-down DC-DC con-
trollers ideal for a variety of cost-sensitive applications.
They drive low-cost n-channel MOSFETs for both the
high-side switch and synchronous rectifier, and require
no external current-sense resistor. These devices can
supply output voltages as low as 0.8V.
The MAX8545/MAX8546/MAX8548 have a wide 2.7V to
28V input range, and do not need any additional bias
voltage. The output voltage can be precisely regulated
from 0.8V to 0.83 x V
IN
. These devices can provide effi-
ciency up to 95%. Lossless short-circuit and current-limit
protection is provided by monitoring the R
DS(ON)
of the
low-side MOSFET. The MAX8545 and MAX8548 have a
current-limit threshold of 320mV, while the MAX8546 has
a current-limit threshold of 165mV. All devices feature
foldback-current capability to minimize power dissipation
under short-circuit condition. Pulling the COMP/EN pin
low with an open-collector or low-capacitance, open-
drain device can shut down all devices.
The MAX8545/MAX8546 operate at 300kHz and the
MAX8548 operates at 100kHz. The MAX8545/MAX8546/
MAX8548 are compatible with low-cost aluminum elec-
trolytic capacitors. Input undervoltage lockout prevents
proper operation under power-sag operations to prevent
external MOSFETs from overheating. Internal soft-start is
included to reduce inrush current. These devices are
offered in space-saving 10-pin µMAX
®
packages.
Applications
Features
♦ 2.7V to 28V Input Range
♦ Foldback Short-Circuit Protection
♦ No Additional Bias Supply Needed
♦ 0.8V to 0.83 x V
IN
Output
♦ Up to 95% Efficiency
♦ Low-Cost External Components
♦ No Current-Sense Resistor
♦ All n-Channel MOSFET Design
♦ Adaptive Gate Drivers Eliminate Shoot-Through
♦ Lossless Overcurrent and Short-Circuit
Protection
♦ 300kHz Switching Frequency
(MAX8545/MAX8546)
♦ 100kHz Switching Frequency (MAX8548)
♦ Pin-Compatible with the MAX1967
♦ Thermal Shutdown
MAX8545/MAX8546/MAX8548
Low-Cost, Wide Input Range, Step-Down
Controllers with Foldback Current Limit
________________________________________________________________ Maxim Integrated Products 1
MAX8545
MAX8546
MAX8548
ON
OFF
OPTIONAL
BSTV
IN
COMP/
EN
VLV
CC
DH
LX
DL
GND
FB
INPUT
2.7V TO 28V
OUTPUT
0.8V TO
0.9 x V
IN
UP TO 6A
Typical Operating Circuit
Ordering Information
Pin Configuration appears at end of data sheet.
19-2795; Rev 2; 6/07
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.
PART
TEMP RANGE
PIN-
PACKAGE
PKG
CODE
MAX8545EUB
-40°C to +85°C
10 µMAX
U10-2
MAX8545EUB+
-40°C to +85°C
10 µMAX
U10-2
MAX8546EUB
-40°C to +85°C
10 µMAX
U10-2
MAX8546EUB+
-40°C to +85°C
10 µMAX
U10-2
MAX8548EUB
-40°C to +85°C
10 µMAX
U10-2
MAX8548EUB+
-40°C to +85°C
10 µMAX
U10-2
Selector Guide
PART
SWITCHING
FREQUENCY
(kHz)
CURRENT-LIMIT
THRESHOLD
(mV)
MAX8545 300 -320
MAX8546 300 -165
MAX8548 100 -320
Set-Top Boxes
Graphic Card and Video
Supplies
Desktops and Desknotes
PCI Express Power
Supplies
Telecom Power Supplies
Notebook Docking
Station Supplies
Cable Modems and
Routers
Networking Power
Supplies
+Denotes a lead-free package.
µMAX is a registered trademark of Maxim Integrated Products, Inc.
MAX8545/MAX8546/MAX8548
Low-Cost, Wide Input Range, Step-Down
Controllers with Foldback Current Limit
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= VL = V
CC
= 5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°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.
(All voltages referenced to GND unless otherwise noted.)
V
IN
to GND ............................................................-0.3V to +30V
V
CC
to GND .............................-0.3V, lower of 6V or (VL + 0.3V)
FB to GND ................................................................-0.3V to +6V
BST to GND ............................................................-0.3V to +36V
VL, DL, COMP to GND ..............................-0.3V to (V
CC
+ 0.3V)
BST to LX..................................................................-0.3V to +6V
DH to LX....................................................-0.3V to (V
BST
+ 0.3V)
VL Short to GND ......................................................................5s
LX to GND ................................................................-1V to +30V
Input Current (any pin) .....................................................±50mA
Continuous Power Dissipation (T
A
= +70°C)
10-Pin µMAX (derate 5.6mW/°C above +70°C) ..........444mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
V
CC
= VL, V
IN
separate from V
CC
4.9
28.0
V
IN
Operating Range V
IN
V
IN
= VL = V
CC
2.7 5.5
V
V
IN
Undervoltage Lockout
(UVLO) Trip Level
Rising and falling edge, hysteresis = 2%
2.35 2.50 2.66
V
V
IN
Operating Supply Current V
FB
= 0.88V (no switching)
0.7
1.2 mA
VL Output Voltage
5.5V < V
IN
< 28V, V
CC
= VL,
1mA < I
LOAD
< 25mA
4.7 5 5.3 V
Thermal Shutdown
Rising temperature, typical
hysteresis = 10°C (Note 1)
+160
°C
OSCILLATOR
MAX8545, MAX8546
250 300
360
Frequency f
OSC
MAX8548 80
100
120
kHz
DH output, MAX8545, MAX8546 5
Minimum Duty Cycle DC
MIN
MAX8548 10
%
DH output, MAX8545, MAX8546 83 86
Maximum Duty Cycle
DC
MAX
MAX8548 90 95
%
SOFT-START
MAX8545, MAX8546 6.6
Digital Ramp Period
MAX8548
10.2
ms
MAX8545, MAX8546 V
OUT
/ 64
Soft-Start Levels
MAX8548
V
OUT
/ 32
V
MAX8545/MAX8546/MAX8548
Low-Cost, Wide Input Range, Step-Down
Controllers with Foldback Current Limit
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= VL = V
CC
= 5V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL
CONDITIONS
TYP
MAX
UNITS
ERROR AMPLIFIER
2.7V < V
CC
< 5.5V, 0°C to +85°C
0.787 0.800 0.815
FB Regulation Voltage
2.7V < V
CC
< 5.5V, -40°C to +85°C
0.782 0.800 0.815
V
FB to COMP/EN Gain
4000
V / V
FB to COMP/EN
Transconductance
-5µA < I
COMP/EN
< +5µA 70
108
160 µS
FB Input Bias Current V
FB
= 0.88V 1 2 µA
COMP/EN Source Current V
COMP/EN
= 0V 15 46 100 µA
LX to GND, MAX8545, MAX8548,
V
FB
= 0.8V
-355 -320 -280
Current-Limit Threshold Voltage
(Across Low-Side MOSFET)
LX to GND MAX8546, V
FB
= 0.8V
-185 -165 -140
mV
LX to GND, V
FB
= 0V,
MAX8545, MAX8548
-105
-75 -45
Foldback Current-Limit Threshold
Voltage (Across Low-Side
MOSFET) When Output is Short
MAX8546, LX to GND, V
FB
= 0 -53 -38 -22
mV
MOSFET DRIVERS
Rising edge, DH going low to DL going high
96
Break-Before-Make Time
Falling edge, DL going low to DH going high
28
ns
DH On-Resistance in Low State 1.6 4 Ω
DH On-Resistance in High State 2.5 5.5 Ω
DL On-Resistance in Low State 1.1 2.5 Ω
DL On-Resistance in High State 2.5 5.5 Ω
BST Leakage Current V
BST
= 33V, V
LX
= 28V, V
FB
= 0.88V 0 50 µA
LX Leakage Current V
BST
= 33V, V
LX
= 28V, V
FB
= 0.88V 33 100 µA
Note 1: Thermal shutdown disables the buck regulator when the die reaches this temperature. Soft-start is reset but the VL regulator
remains on.
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18

MAX8546EUB+T

Mfr. #:
Buy MAX8546EUB+T
Manufacturer:
Maxim Integrated
Description:
Switching Controllers Wide Input Range Step-Down Controller
Lifecycle:
New from this manufacturer.
Delivery:
DHL FedEx Ups TNT EMS
Payment:
T/T Paypal Visa MoneyGram Western Union

Products related to this Datasheet