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MAX8544EEP+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27
General Description
The MAX8543/MAX8544 current-mode, constant-fre-
quency PWM buck controllers operate from a 3V to
13.2V input supply and generate adjustable 0.8V to 0.9
x V
IN
output voltages at loads up to 25A. They feature
adjustable switching frequency and synchronization for
noise-sensitive applications.
The MAX8543/MAX8544 can start with (or without) a pre-
existing bias on the output, without discharging the out-
put. This feature simplifies tracking supply designs for
core and I/O applications and redundant supply designs.
The MAX8543/MAX8544 use the DC resistance of the
output inductor as the current-sense element for loss-
less, low-cost current sensing. The current-sense
threshold can be set to four discrete levels to accom-
modate inductors with different DC resistance values.
The MAX8544 features a power-OK monitor and two
MAX8544 controllers that can operate at 180° out-of-
phase for dual-output applications.
Applications
Base Stations
Networks and Telecom
Storage
Servers
Features
♦ Prebias Startup/Monotonic
♦ 1% Output Accuracy
♦ Ceramic, Polymer, or Electrolytic Capacitors
♦ 200kHz to 1MHz Adjustable Frequency
♦ 160kHz to 1.2MHz Synchronization
♦ Lossless, Foldback Current Limit
♦ Overvoltage Protection
♦ Enable (On/Off)
♦ Adjustable Soft-Start
♦ MAX8544
Latch-Off/Autorecovery
Power-OK Monitor
Out-of-Phase Clock Output
MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
MAX8543
ON
OPTIONAL
SYNCHRONIZATION
OFF
BST
VL
V
IN
= 3V
TO 5.5V
COMP
ILIM
FSYNC
EN
SS
PGND
GND
IN
DH
LX
DL
CS+
CS-
FB
INPUT 3V TO 13.2V
OUTPUT
0.8V TO 0.9 x V
IN
UP TO 25A
POK (MAX8544)
Typical Operating Circuit
19-3155; Rev 0; 5/04
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
PART TEMP RANGE
PIN-PACKAGE
MAX8543EEE -40°C to +85°C 16 QSOP
MAX8544EEP -40°C to +85°C 20 QSOP
Pin Configurations appear at end of data sheet.
MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
IN
= 13.2V, V
BST
- V
LX
= 5V, T
A
= 0°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.
IN, EN, CS+, CS- to GND .......................................-0.3V to +14V
BST, DH to LX ..........................................................-0.3V to +6V
BST to GND ............................................................-0.3V to +20V
DL, COMP, ILIM2, SS, SYNCO,
FSYNC to GND .......................................-0.3V to (V
VL
+ 0.3V)
VL, FB, POK, ILIM1, ILIM, MODE to GND ................-0.3V to +6V
PGND to GND .......................................................-0.3V to +0.3V
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate 8.3mW/°C above +70°C) .......666.7mW
20-Pin QSOP (derate 9.1mW/°C above +70°C) .......727.3mW
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 CONDITIONS
MIN TYP MAX
UNITS
Operating Input Voltage Range VL connected to IN for V
IN
< 5.5V 3.0
13.2
V
Quiescent Supply Current V
FB
= 0.9V, no switching 2 3 mA
EN = GND, MODE = GND, IN not connected to VL
10
Shutdown Supply Current
EN = GND, VL = IN, MODE = GND 20
µA
VL Undervoltage-Lockout Trip Level V
VL
rising, typical hysteresis is 80mV
2.52
2.7
2.88
V
Output Voltage Adjust Range (V
OUT
) (Note 1) 0.8 V
VL Output Voltage 5.5V < V
IN
< 13.2V, 1mA < I
VL
< 75mA 4.5 5 5.5 V
VL Output Current 75 mA
VOLTAGE REFERENCE
SS Shutdown Resistance From SS to GND, V
EN
= 0V 20
100
Ω
SS Soft-Start Current V
REF
= 0.625V 14 24 34 µA
Soft-Start Ramp Time Output from 0% to 100%, C
REF
= 0.01µF to 1µF 33
ms/µF
ERROR AMPLIFIER
FB Regulation Voltage
0.792
0.8
0.808
V
Transconductance 70
110 160
µS
COMP Shutdown Resistance From COMP to GND, V
EN
= 0V 20
100
Ω
FB Input Leakage Current V
FB
= 0.9V 5
100
nA
FB Input Common-Mode Range
-0.1
+0.9
V
CURRENT-SENSE AMPLIFIER
V
ILIM1
= 0V 8.8 11
13.2
V
ILIM1
= (1/3)V
VL
4.8 6 7.2
V
ILIM1
= (2/3)V
VL
3.2 4 4.8
Voltage Gain V
OUT
= 0 to 13V
V
ILIM1
= V
VL
2.4 3 3.6
V / V
CURRENT LIMIT
ILIM2 Output Current (MAX8544 Only) R
ILIM2
= 50kΩ to 200kΩ 4.5 5 5.5 µA
ILIM1 Input Current V
ILIM1
= 0V or V
VL
-1 +1 µA
MAX8543/MAX8544
Step-Down Controllers with Prebias Startup,
Lossless Sensing, Synchronization, and OVP
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= 13.2V, V
BST
- V
LX
= 5V, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER CONDITIONS
MIN
TYP
UNITS
V
CS+
- V
CS-
,
V
ILIM1
= 0V
38.5
50
56.5
V
CS+
- V
CS-
,
V
ILIM1
= (1/3)V
VL
85
100 115
V
CS+
- V
CS-
, V
ILIM1
= (2/3)V
VL
127.5 150 172.5
V
CS+
- V
CS-
,
V
ILIM1
= V
VL
170 200 230
V
LX
- V
PGND
, R
ILIM2
= 50kΩ (MAX8544 only)
-42.5
-50
-57.5
V
LX
- V
PGND
, R
ILIM2
= 200kΩ (MAX8544 only)
-160 -200 -240
V
LX
- V
PGND
, V
FB
= 0.8V (MAX8543 only)
-110 -130 -150
Current-Limit Threshold
V
LX
- V
PGND
, V
FB
= 0V (MAX8543 only) -20 -30 -40
mV
Negative Current-Limit Threshold % of positive-direction current limit V
LX
- V
PGND
-25 -50 -85 %
CS+, CS- Input Current V
CS+
= V
CS-
= 0 or 5V -40
+40
µA
CS+, CS- Input Common-Mode Range 0
13.2
V
OSCILLATOR
R
FSYNC
= 18.2kΩ
800 1000 1200
Switching Frequency
R
FSYNC
= 158kΩ
200
kHz
Minimum Off-Time Measured at DH
150 220 270
ns
Minimum On-Time Measured at DH 90
145
ns
FSYNC Synchronization Range
160
1200
kHz
FSYNC Input High Pulse Width
100
ns
FSYNC Input Low Pulse Width
100
ns
FSYNC Rise/Fall Time
100
ns
SYNCO Phase Shift from DH Rising
R
FSYNC
= 18.2kΩ, free-running mode,
at maximum duty cycle
165 180 195
Degrees
SYNCO Output Low Level I
SYNCO
= 5mA 0.4 V
SYNCO Output High Level I
SYNCO
= 5mA
V
VL
- 1V
V
MOSFET DRIVERS
(V
BST
- V
LX
) = 5V 1 2.5
DH On-Resistance, High State
(V
BST
- V
LX
) = 3V 1.2
Ω
(V
BST
- V
LX
) = 5V 1 2.5
DH On-Resistance, Low State
(V
BST
- V
LX
) = 3V 1.2
Ω
V
VL
= 5V 1 2.5
DL On-Resistance, High State
V
VL
= 3V 1.2
Ω
V
VL
= 5V 0.6 1.7
DL On-Resistance, Low State
V
VL
= 3V 0.8
Ω
Low-side off to high-side on 55
Break-Before-Make Dead Time
High-side off to low-side on 40
ns
LX, BST, IN Leakage Current V
BST
= 18.7V, V
LX
= 13.2V, V
IN
= 13.2V 5 µA
THERMAL PROTECTION
Thermal Shutdown Rising temperature
+160
°C
Thermal-Shutdown Hysteresis 15 °C
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P21P22-P24P25-P27

MAX8544EEP+T

Mfr. #:
Buy MAX8544EEP+T
Manufacturer:
Maxim Integrated
Description:
Switching Controllers Step-Down Controller
Lifecycle:
New from this manufacturer.
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