19-2740; Rev 1; 6/09
IT
TION K
VALUA
E
BLE
AVAILA
2.35V to 5.5V, 0.5% Accurate, 1MHz PWM
Step-Down Controllers with Voltage Margining
General Description
The MAX1960/MAX1961/MAX1962 high-current, high-
efficiency voltage-mode step-down DC-DC controllers
operate from a 2.35V to 5.5V input and generate output
voltages down to 0.8V at up to 20A. An on-chip charge
pump generates a regulated 5V for MOSFET drive.
Additionally, adaptive dead-time drivers allow a
wide variety of MOSFETs to be used without risking
shoot-through.
Fixed-frequency PWM operation and external synchro-
nization make these controllers suitable for telecom
and datacom applications. The operating frequency is
programmable to either 500kHz or 1MHz, or from
450kHz to 1.2MHz with an external clock. A clock output
is provided to synchronize another converter for 180°
out-of-phase operation. A high closed-loop bandwidth
provides excellent transient response for applications
with dynamic loads.
Lossless current sensing in the MAX1960 and
MAX1961 is achieved by monitoring the drain-to-source
voltage of the low-side external FET. The current limit is
scalable to accommodate a wide variety of MOSFETs
and load currents. The MAX1962 has 10% accurate
sense-resistor-based current limiting.
The MAX1960 and MAX1962 have an adjustable output
voltage from 0.8V to 4.95V. The MAX1961 and
MAX1962 have four preset output voltages (1.5V, 1.8V,
2.5V, and 3.3V) and feature 0.5% voltage accuracy
over temperature, line, and load variations. The
MAX1960 and MAX1961 also feature voltage-margining
control inputs that shift the output voltage up or down
by 4% for system testing.
Features
o
0.5% Accurate Output
o
Operates from 2.35V to 5.5V Supply
o
Generates Low Output Voltage Down to 0.8V
o
o
o
o
o
o
o
o
o
o
On-Chip Charge Pump Provides 5V Gate Drive
Ceramic or Electrolytic Capacitors
94% Efficiency
External Synchronization from 450kHz to 1.2MHz
500kHz/1MHz Fixed-Frequency PWM Operation
Fast Transient Response
Two Converters Can Operate 180° Out-of-Phase
±4% Voltage Margining for System Test
10% Accurate Current Sensing (MAX1962)
Adaptive Dead Time Prevents Shoot-Through
MAX1960/MAX1961/MAX1962
Ordering Information
PART
MAX1960EEP
MAX1961EEP
MAX1962EEP
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
20 QSOP
20 QSOP
20 QSOP
Typical Operating Circuit
INPUT
2.35V TO 5.5V
C+
V
CC
C-
AV
DD
MAX1960
V
DD
Applications
ASIC, FPGA, DSP, and CPU Core and I/O Voltages
Cellular Base Stations
Telecom and Network Equipment
Server and Storage Systems
VOLTAGE
MARGINING
AND ON/OFF
CTL1
BST
CTL2
COMP
DH
OUTPUT
0.8 TO 0.87
✕
V
IN
UP TO 20A
REF
LX
DL
GND
PGND
ILIM
OPTIONAL
SYNCHRONIZATION
FSET/SYNC
Pin Configurations and Selector Guide appear at the end
of the data sheet.
CLKOUT
180° OUT-OF-PHASE
CLKOUT
FB
________________________________________________________________
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.
2.35V to 5.5V, 0.5% Accurate, 1MHz PWM
Step-Down Controllers with Voltage Margining
MAX1960/MAX1961/MAX1962
ABSOLUTE MAXIMUM RATINGS
V
CC
, CTL_, CS, FSET/SYNC, SEL, EN,
OUT to GND ..........................................................-0.3V to +6V
ILIM, COMP, REF, FB, CLKOUT,
C- to GND ..............................................-0.3V to V
AVDD
+ 0.3V
C+ to GND.............-0.3V to higher of V
VCC
+ 1V or V
VDD
+ 0.3V
V
DD
, AV
DD
to GND ..............-0.3V to higher of V
VCC
- 0.3V or 6V
DL to PGND ................................................-0.3V to V
VDD
+ 0.3V
BST to GND ............................................................-0.3V to +12V
DH to LX ...................................................................-0.3V to +6V
LX to BST..................................................................-6V to +0.3V
PGND to GND, or V
DD
to AV
DD
............................-0.3V to +0.3V
Continuous Power Dissipation (T
A
= +70°C)
20-Pin QSOP (derate up to +70°C)..............................727mW
20-Pin QSOP (derate above +70°C) ........................9.1mW/°C
Operating Temperature Range (Extended).........-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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
VCC
= 3.3V, Circuits of Figures 9–12,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
V
CC
Input Voltage Range
V
CC
Input Voltage UVLO
V
DD
Input Voltage UVLO
Output Voltage
MAX1960/MAX1962 (measured at FB)
DC Output Accuracy
SEL = GND
MAX1961/
SEL = REF
MAX1962 (FB = V
DD
),
SEL not connected
measured at output
SEL = V
DD
MAX1960/MAX1961
MAX1960/MAX1961
0V to full load
V
VCC
= 2.7V to 5.5V
-0.2
1
In shutdown
FSET/SYNC = GND
FSET/SYNC = V
CC
f = 1MHz
f = 500kHz
450
880
450
80
90
83
92
11
15
15
2
10
1280
500
1000
550
1120
1200
Rising or falling, hysteresis = 33mV (typ)
Rising or falling, hysteresis = 44mV (typ)
CONDITIONS
MIN
2.35
1.95
3.9
0.8
0.796
1.492
1.791
2.487
3.272
+3.8
-3.8
0.800
1.500
1.800
2.500
3.300
+4
-4
0.08
0.1
+0.2
3
100
0.804
1.508
1.809
2.514
3.336
+4.2
-4.2
%
%
%
%
µA
mS
Ω
cycles
kHz
kHz
%
%
mA
µA
V
TYP
MAX
5.5
2.3
4.45
UNITS
V
V
V
V
Positive Voltage-Margining Shift
Negative Voltage-Margining Shift
Load Regulation Error
Line Regulation Error
FB Input Bias Current
Feedback Transconductance
COMP Discharge Resistance
DC-DC Soft-Start Time
Switching Frequency
SYNC Frequency Range
Maximum Duty Cycle
Maximum Duty Cycle
Quiescent Supply Current
Shutdown Supply Current
2
_______________________________________________________________________________________
2.35V to 5.5V, 0.5% Accurate, 1MHz PWM
Step-Down Controllers with Voltage Margining
ELECTRICAL CHARACTERISTICS (continued)
(V
VCC
= 3.3V, Circuits of Figures 9–12,
T
A
= 0°C to +85°C.
Typical values are at T
A
= +25°C, unless otherwise noted.)
PARAMETER
CONDITIONS
2.7V
≤
V
VCC
≤
5.5V, I
LOAD
= 1mA to 50mA
V
DD
Output Voltage
2.35V
≤
V
VCC
≤
2.7V, I
LOAD
= 1mA to 35mA, C1
= 4.7µF, C6 = 22µF (Note 1)
2.35V
≤
V
VCC
≤
3.6V with tripler, I
LOAD
= 1 to
50mA (circuit of Figure 12) (Note 1)
Reference Voltage (No Load)
Reference Load Regulation
Positive Current-Limit Threshold
(V
PGND
- V
LX
)
Negative Current-Limit Threshold
(V
LX
- V
PGND
)
CS Bias Current
OUT Bias Current
Current-Limit Threshold (Positive
Direction, Fixed, V
PGND
- V
LX
)
Current-Limit Threshold (Negative
Direction, Fixed, V
LX
- V
PGND
)
Current-Limit Threshold (Positive
Direction, Adjustable, V
PGND
- V
LX
)
Current-Limit Threshold (Negative
Direction, Adjustable, V
LX
- V
PGND
)
Thermal-Shutdown Threshold
DH Gate-Driver On-Resistance
DL Gate-Driver On-Resistance (Pullup)
DL Gate-Driver On-Resistance (Pulldown)
Minimum Adaptive Dead Time
FSET/SYNC Pulse Width
FSET/SYNC Rise/Fall Time
CTL_, FSET/SYNC, EN Input High Voltage
CTL_, FSET/SYNC, EN Input Low Voltage
CTL_, FSET/SYNC, EN Input Current
CLKOUT V
OL
CLKOUT V
OH
CLKOUT Rise/Fall Time
Sinking 1mA
Sourcing 1mA
C
LOAD
= 100pF (Note 1)
V
VCC
-
0.2V
-50µA to +50µA
V
OUT
= 0.8V
MAX1962
V
OUT
= 2.0V
V
OUT
= 3.3V
MAX1962, V
OUT
= 0.8V to 3.3V
MAX1962, V
CS
= 3.3V
MAX1961/MAX1962, V
OUT
= 3.3V
MAX1960/MAX1961, ILIM = V
DD
MAX1960/MAX1961, ILIM = V
DD
MAX1960/MAX1961, R
ILIM
= 160kΩ
R
ILIM
= 400kΩ
MAX1960/MAX1961, R
ILIM
= 160kΩ
R
ILIM
= 400kΩ
15°C hysteresis
V
BST
- V
LX
= 5V, pulling up or down
DL high state
DL low state
DH falling to DL rising
DH rising to DL falling
Minimum high time (Note 1)
Minimum low time (Note 1)
(Note 1)
V
VCC
= 2.35V to 5.5V
V
VCC
= 2.35V to 5.5V
-1
0.01
V
VCC
-
0.01V
40
2.0
0.8
+1
0.1
200
200
100
58
50
100
250
90
245
44
45
38
38
MIN
4.75
4.45
4.75
1.269
1.280
3
53
50
48
50
20
30
74
67
114
279
107
271
+160
1.8
1.8
0.5
35
26
TYP
MAX
5.25
5.25
5.25
1.291
62
55
58
68
50
50
90
85
135
306
125
296
3.5
3.5
1.6
mV
µA
µA
mV
mV
mV
mV
°C
Ω
Ω
Ω
ns
ns
ns
V
V
µA
V
V
ns
mV
UNITS
V
V
V
V
mV
MAX1960/MAX1961/MAX1962
_______________________________________________________________________________________
3
2.35V to 5.5V, 0.5% Accurate, 1MHz PWM
Step-Down Controllers with Voltage Margining
MAX1960/MAX1961/MAX1962
ELECTRICAL CHARACTERISTICS
(V
VCC
= 3.3V, Circuits of Figures 9–12,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
V
CC
Input Voltage Range
V
CC
Input Voltage UVLO
V
DD
Input Voltage UVLO
Output Voltage
MAX1960/MAX1962 (measured at FB)
SEL = GND
DC Output Accuracy
MAX1961/MAX1962
(FB = V
DD
),
measured at output
MAX1960/MAX1961
MAX1960/MAX1961
SEL = REF
SEL not connected
SEL = V
DD
Positive Voltage-Margining Shift
Negative Voltage-Margining Shift
FB Input Bias Current
Feedback Transconductance
COMP Discharge Resistance
Switching Frequency
SYNC Frequency Range
Maximum Duty Cycle
Maximum Duty Cycle
Quiescent Supply Current
Shutdown Supply Current
2.7V
≤
V
VCC
≤
5.5V, I
LOAD
= 1mA to 50mA
V
DD
Output Voltage
2.35V
≤
V
VCC
≤
2.7V, I
LOAD
= 1mA to 35mA,
C1 = 4.7µF, C6 = 22µF
2.35V
≤
V
VCC
≤
3.6V with tripler, I
LOAD
= 1mA
to 50mA (circuit of Figure 12)
Reference Voltage (No Load)
Positive Current-Limit Threshold
(V
CS
- V
OUT
)
Negative Current-Limit Threshold
(V
OUT
- V
CS
)
CS Bias Current
OUT Bias Current
Current-Limit Threshold (Positive
Direction, Fixed, V
PGND
- V
LX
)
Current-Limit Threshold (Negative
Direction, Fixed, V
LX
- V
PGND
)
Current-Limit Threshold (Positive
Direction, Adjustable, V
PGND
- V
LX
)
MAX1962, V
OUT
= 2V
MAX1962, V
OUT
= 2V
MAX1962, V
CS
= 3.3V
MAX1961/MAX1962, V
OUT
= 3.3V
MAX1960/MAX1961, ILIM = V
DD
MAX1960/MAX1961, ILIM = V
DD
MAX1960/MAX1961, R
ILIM
= 160kΩ
R
ILIM
= 400kΩ
58
50
100
250
4.75
4.45
4.75
1.267
45
42
f = 1MHz
f = 500kHz
In shutdown
FSET/SYNC = GND
FSET/SYNC = V
CC
450
880
450
80
90
15
15
5.25
5.25
5.25
1.291
56
64
50
50
90
85
135
306
V
mV
mV
µA
µA
mV
mV
mV
V
Rising or falling
Rising or falling
CONDITIONS
MIN
2.35
1.95
3.90
0.8
0.795
1.492
1.789
2.482
3.272
3.8
-3.8
-0.2
1
0.805
1.508
1.809
2.517
3.339
4.2
-4.2
+0.2
3
100
550
1120
1200
%
%
µA
mS
Ω
kHz
kHz
%
%
mA
µA
V
TYP
MAX
5.50
2.3
4.45
UNITS
V
V
V
V
4
_______________________________________________________________________________________
2.35V to 5.5V, 0.5% Accurate, 1MHz PWM
Step-Down Controllers with Voltage Margining
ELECTRICAL CHARACTERISTICS (continued)
(V
VCC
= 3.3V, Circuits of Figures 9–12,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Current-Limit Threshold (Negative
Direction, Adjustable, V
LX
- V
PGND
)
DH Gate-Driver On-Resistance
DL Gate-Driver On-Resistance (Pullup)
DL Gate-Driver On-Resistance (Pulldown)
FSET/SYNC Pulse Width
FSET/SYNC Rise/Fall Time
CTL_, FSET/SYNC, EN Input High Voltage
CTL_, FSET/SYNC, EN Input Low Voltage
CTL_, FSET/SYNC, EN Input Current
CLKOUT V
OL
CLKOUT V
OH
CLKOUT Rise/Fall Time
Sinking 1mA
Sourcing 1mA
C
LOAD
= 100pF
V
VCC
-
0.2V
40
V
VCC
= 2.35V to 5.5V
V
VCC
= 2.35V to 5.5V
-1
2.0
0.8
+1
0.1
R
ILIM
= 400kΩ
V
BST
- V
LX
= 5V, pulling up or down
DL high state
DL low state
Minimum high time
Minimum low time
200
200
100
CONDITIONS
MAX1960/MAX1961, R
ILIM
= 160kΩ
MIN
90
245
TYP
MAX
125
296
3.5
3.5
1.6
UNITS
mV
Ω
Ω
Ω
ns
ns
V
V
µA
V
V
ns
MAX1960/MAX1961/MAX1962
Note 1:
Guaranteed by design.
Note 2:
Specifications at -40°C are guaranteed by design, and not production tested.
_______________________________________________________________________________________
5
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