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MAX1649EPA

P1-P3P4-P6P7-P9P10-P12
_______________General Description
The MAX1649/MAX1651 BiCMOS, step-down, DC-DC
switching controllers provide high efficiency over loads
ranging from 1mA to more than 2.5A. A unique, current-
limited pulse-frequency-modulated (PFM) control scheme
gives these devices the benefits of pulse-width-modula-
tion (PWM) converters (high efficiency at heavy loads),
while using only 100µA of supply current (vs. 2mA to
10mA for PWM converters). Dropout performance down
to 300mV is provided by a high switch duty cycle (96.5%)
and a low current-sense threshold (110mV).
A high switching frequency (up to 300kHz) allows these
devices to use miniature external components.
The MAX1649/MAX1651 have dropout voltages less
than 0.3V at 500mA and accept input voltages up to
16V. Output voltages are preset at 5V (MAX1649), or
3.3V (MAX1651). They can also be adjusted to any
voltage from 1.5V to the input voltage by using two
resistors.
These step-down controllers drive external P-channel
MOSFETs at loads greater than 12.5W. If less power is
required, use the MAX639/MAX640/MAX653 step-down
converters with on-chip FETs, which allow up to a
225mA load current.
________________________Applications
PDAs
High-Efficiency Step-Down Regulation
5V-to-3.3V Green PC Applications
Battery-Powered Applications
____________________________Features
♦ More than 90% Efficiency (10mA to 1.5A Loads)
♦ More than 12.5W Output Power
♦ Less than 0.3V Dropout Voltage at 500mA
♦ 100µA Max Quiescent Supply Current
♦ 5µA Max Shutdown Supply Current
♦ 16V Max Input Voltage
♦ 5V (MAX1649), 3.3V (MAX1651), or Adjustable
Output Voltage
♦ Current-Limited Control Scheme
♦ Up to 300kHz Switching Frequency
♦ Up to 96.5% Duty Cycle
______________Ordering Information
*Dice are tested at T
A
= +25°C.
MAX1649/MAX1651
5V/3.3V or Adjustable, High-Efficiency,
Low-Dropout, Step-Down DC-DC Controllers
________________________________________________________________ Maxim Integrated Products 1
1
2
3
4
8
7
6
5
GND
EXT
CS
V+
REF
SHDN
FB
OUT
DIP/SO
TOP VIEW
MAX1649
MAX1651
__________________Pin Configuration
__________Typical Operating Circuit
19-0305; Rev 3; 3/09
PART TEMP RANGE PIN-PACKAGE
MAX1649CPA
0°C to +70°C 8 Plastic DIP
MAX1649CSA 0°C to +70°C 8 SO
MAX1649C/D 0°C to +70°C Dice*
MAX1649EPA -40°C to +85°C 8 Plastic DIP
MAX1649ESA -40°C to +85°C 8 SO
MAX1651
V+
CSSHDN
FB GND
ON/OFF
P
EXT
REF
OUT
OUTPUT
3.3V
INPUT
3.6V TO 16V
MAX1651CPA
0°C to +70°C 8 Plastic DIP
MAX1651CSA 0°C to +70°C 8 SO
MAX1651C/D 0°C to +70°C Dice*
MAX1651EPA -40°C to +85°C 8 Plastic DIP
MAX1651ESA -40°C to +85°C 8 SO
EVALUATION KIT
AVAILABLE
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.
MAX1649/MAX1651
5V/3.3V or Adjustable, High-Efficiency,
Low-Dropout, Step-Down DC-DC Controllers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 5V, T
A
= T
MIN
to T
MAX
, 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.
PARAMETER SYMBOL MIN TYP MAX UNITS
1.4625 1.5 1.5375
FB Trip Point
1.470 1.5 1.530
V
I+
15
FB Input Current I
FB
±50
nA
±70
Output Voltage V
OUT
4.80 5.0 5.20
V
Supply Current
V+ Input Voltage Range V+ 3.0 16 V
78 100
µA
2
3.17 3.3 3.43
Reference Voltage V
REF
1.470 1.5 1.530
V
1.4625 1.5 1.5375
REF Load Regulation mV410
CONDITIONS
MAX1649E, MAX1651E
MAX1649, V+ = 5.5V to 16V
MAX1649C, MAX1651C
V+ = 10V, SHDN ≥ 1.6V (shutdown)
MAX1649C, MAX1651C
MAX1649C, MAX1651C, I
REF
= 0μA
MAX1649E, MAX1651E
MAX1649E, MAX1651E, I
REF
= 0μA
V
OUT
< V+
V+ = 16V, SHDN ≤ 0.4V (operating, switch off)
V+ = 16V, SHDN ≥ 1.6V (shutdown)
Supply Voltage, V+ to GND.......................................-0.3V, +17V
REF, SHDN, FB, CS, EXT, OUT .......................-0.3V, (V+ + 0.3V)
Continuous Power Dissipation (T
A
= +70°C)
Plastic DIP (derate 9.09mW/°C above +70°C) .............727mW
SO (derate 5.88mW/°C above +70°C)..........................471mW
Operating Temperature Ranges
MAX1649C_A, MAX1651C_A ..............................0°C to +70°C
MAX1649E_A, MAX1651E_A............................-40°C to +85°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10sec) .............................+300°C
0µA ≤ I
REF
≤ 100µA, sourcing only
3V ≤ V+ ≤ 16VREF Line Regulation 40 100 µV/V
2.6
mV/V
1.7
Output Voltage
Line Regulation
Circuit of
Figure 1
MAX1649, 5.5V ≤ V+ ≤ 16V,
I
LOAD
= 1A
MAX1651, 3.6V ≤ V+ ≤ 16V,
I
LOAD
= 1A
-47
mV/A
MAX1649, 0A ≤ I
LOAD
≤ 1.5A,
V
IN
= 10V
MAX1651, 0A ≤ I
LOAD
≤ 1.5A,
V
IN
= 5V
-45
Output Voltage
Load Regulation
Circuit of
Figure 1
90
%
MAX1649, V+ = 10V,
I
LOAD
= 1A
MAX1651, V+ = 5V,
I
LOAD
= 1A
90
Efficiency
Circuit of
Figure 1
SHDN Input Current V+ = 16V, SHDN = 0V or V+ 1 µA
SHDN Input Voltage High V
IH
3V ≤ V+ ≤ 16V 1.6 V
SHDN Input Voltage Low V
IL
3V ≤ V+ ≤ 16V 0.4 V
MAX1651, V+ = 3.6V to 16V
MAX1649/MAX1651
5V/3.3V or Adjustable, High-Efficiency,
Low-Dropout, Step-Down DC-DC Controllers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SYMBOL MIN TYP MAX UNITSCONDITIONS
3V ≤ V+ ≤ 16VCS Input Current ±1 µA
C
EXT
= 0.001µF, V+ = 12VEXT Rise Time 25 ns
C
EXT
= 0.001µF, V+ = 12VEXT Fall Time 25 ns
Current-Limit Trip Level
(V+ to CS)
mVV
CS
3V ≤ V+ ≤ 16V 80 110 140
t
ON
t
ON
+ t
OFF
x 100%
Maximum Duty Cycle 95 96.5 %
80
66
SUPPLY CURRENT vs. TEMPERATURE
68
78
I+ (μA)
76
74
-60 -20 60 140
MAX1649-TOC06
TEMPERATURE (°C)
20 100-40 0 8040 120
72
70
V+ = 10V
V+ = 16V
V+ = 4V
4.0
0
SHUTDOWN CURRENT
vs. TEMPERATURE
0.5
3.5
I+ (μA)
3.0
2.5
-60 -20 60 140
MAX1649-TOC05
TEMPERATURE (°C)
20 100-40 0 8040 120
2.0
1.5
V+ = 8V
V+ = 16V
V+ = 4V
1.0
V+ = 12VSwitch Maximum On-Time 24 32 40 µst
ON
(max)
V+ = 12VSwitch Minimum Off-Time 0.8 1.1 1.8 µst
OFF
(min)
-60 -20 60 140
EXT RISE AND FALL TIMES
vs. TEMPERATURE (1nF)
MAX1649/51-01
TEMPERATURE (°C)
t
RISE
& t
FALL
(ns)
20 100-40 0 8040 120
60
55
50
45
40
35
30
25
20
15
V+ = 15V, t
FALL
V+ = 15V, t
RISE
V+ = 5V, t
FALL
V+ = 5V, t
RISE
C
EXT
= 1nF
1 10 10k
LOAD CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
60
50
40
100 1k
0.1
MAX1649/51-A1
EFFICIENCY
vs. LOAD CURRENT (V
OUT
= 5V)
V
OUT
= 5V
CIRCUIT OF
FIGURE 1
TOP TO
BOTTOM:
V
IN
= 6V
V
IN
= 8V
V
IN
= 10V
V
IN
= 12V
V
IN
= 15V
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
40
-60 -20 60 140
EXT RISE AND FALL TIMES
vs. TEMPERATURE (5nF)
80
MAX1649/51-02
TEMPERATURE (°C)
t
RISE
& t
FALL
(ns)
20 100-40 0 8040 120
60
100
140
120
160
200
180
240
220
V+ = 15V, t
FALL
V+ = 15V, t
RISE
V+ = 5V, t
FALL
V+ = 5V, t
RISE
C
EXT
= 5nF
1 10 10k
LOAD CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
60
50
40
100 1k
0.1
MAX1649/51-A2
EFFICIENCY
vs. LOAD CURRENT (V
OUT
= 3.3V)
V
OUT
= 3.3V
CIRCUIT OF
FIGURE 1
TOP TO
BOTTOM:
V
IN
= 4.3V
V
IN
= 5V
V
IN
= 8V
V
IN
= 10V
V
IN
= 12V
V
IN
= 15V
P1-P3P4-P6P7-P9P10-P12

MAX1649EPA

Mfr. #:
Buy MAX1649EPA
Manufacturer:
Maxim Integrated
Description:
LDO Voltage Controllers 5V/3.3V or Adjustable, High-Efficiency, Low-Dropout, Step-Down DC-DC Controller
Lifecycle:
New from this manufacturer.
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