_______________General Description
The MAX750A/MAX758A are adjustable-output, CMOS,
step-down, DC-DC switching regulators. The
MAX758A accepts inputs from 4V to 16V and delivers
750mA, while the MAX750A accepts inputs from 4V to
11V and delivers 450mA. Typical efficiencies are 85%
to 90%. Typical quiescent current is 1.7mA, or only
6A in shutdown mode. The output does not exhibit
any ripple at subharmonics of the switching frequency
over its specified range.
Pulse-width-modulation (PWM) current-mode control
provides precise output regulation and excellent tran-
sient responses. Output voltage accuracy is guaran-
teed to be 4.5% plus feedback-resistor tolerance over
line, load, and temperature variations. Fixed-frequency
switching and absence of subharmonic ripple allows
easy filtering of output ripple and noise, as well as the
use of small external components. These regulators
require only a single inductor value to work in most
applications, so no inductor design is necessary.
________________________Applications
Cellular Phones & Radios
Portable Communications Equipment
Portable Instruments
Computer Peripherals
____________________________Features
o
Up to 750mA Load Currents
o
160kHz High-Frequency, Current-Mode PWM
o
85% to 96% Efficiencies
o
33H or 100H Pre-Selected Inductor Value,
No Component Design Required
o
1.7mA Quiescent Supply Current
o
6A Shutdown Supply Current
o
Adjustable Output Voltage
o
Overcurrent, Soft-Start, and Undervoltage
Lockout Protection
o
Cycle-by-Cycle Current Limiting
o
8-Pin DIP/SO Packages (MAX750A)
______________Ordering Information
Ordering Information continued on last page.
* Contact factory for dice specifications.
**Contact factory for availability and processing to MIL-STD-883.
MAX750A/MAX758A
Adjustable, Step-Down,
Current-Mode PWM Regulators
________________________________________________________________
Maxim Integrated Products
1
1
2
3
4
8
7
6
5
V+
LX
GND
I.C.
CC
SS
REF
SHDN
DIP
TOP VIEW
MAX750A
MAX758A
1
2
3
4
8
7
6
5
V+
LX
GND
I.C.
CC
SS
REF
MAX750A
SO
SHDN
_________________Pin Configurations
OUTPUT ADJ.
FROM
VREF TO V+
INPUT
4V TO 16V
LX
CC
GND
SS
MAX750A
MAX758A
SHDN
V+
REF
33H
ON/OFF
__________Typical Operating Circuit
Call toll free 1-800-998-8800 for free samples or literature.
19-0195; Rev 0; 10/93
PART
TEMP. RANGE
PIN-PACKAGE
MAX750A
CPA
0C to +70C
8 Plastic DIP
MAX750ACSA
0C to +70C
8 SO
MAX750AC/D
0C to +70C
Dice*
MAX750AMJA
-55C to +125C
8 CERDIP**
MAX750AESA
-40C to +85C
8 SO
MAX750AEPA
-40C to +85C
8 Plastic DIP
Pin Configurations continued on last page.
MAX750A/MAX758A
Adjustable, Step-Down,
Current-Mode PWM Regulators
2
_______________________________________________________________________________________
Pin Voltages
V+ (MAX750A).........................................................+12V, -0.3V
V+ (MAX758A).........................................................+18V, -0.3V
LX (MAX750A) ....................................(V+ - 12V) to (V+ + 0.3V)
LX (MAX758A) ....................................(V+ - 21V) to (V+ + 0.3V)
SS, CC,
SHDN.............................................-0.3V to (V+ + 0.3V)
Peak Switch Current (I
LX
).........................................................2A
Reference Current (I
REF
) ...................................................2.5mA
Power Dissipation (T
A
= +70C)
8-Pin Plastic DIP (derate 9.09mW/C above +70C) .....727mW
8-Pin SO (derate 5.88mW/C above +70C)..................471mW
16-Pin Wide SO (derate 9.52mW/C above +70C) ......762mW
8-Pin CERDIP (derate 8.00mW/C above +70C)..........640mW
Operating Temperature Ranges:
MAX75_AC_ _ .......................................................0C to +70C
MAX75_AE_ _ ....................................................-40C to +85C
MAX75_AMJA ..................................................-55C to +125C
Junction Temperatures:
MAX75_AC_ _/AE_ _ ......................................................+150C
MAX75_AMJA ................................................................+175C
Storage Temperature Range .............................-65C to +160C
Lead Temperature (soldering, 10sec) .............................+300C
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 3, V+ = 9V for the MAX750A, V+ = 12V for the MAX758A, V
OUT
= 5V, R2 = 40.20k
, R3 = 13.0k
, I
LOAD
= 0mA,
T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
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
UNITS
Load Regulation
0.0005
%/V
Line Regulation
0.15
Input Voltage Range
4.0
11.0
V
%/mA
Efficiency
92
%
Supply Current
1.7
3.0
mA
4.75
5.00
5.25
Output Voltage
(Note 1)
V
6.0
100.0
A
2.0
Shutdown Input
Threshold
0.25
V
1.0
A
Short-Circuit Current
1.5
A
CONDITIONS
SHDN = 0V
I
LOAD
= 0mA to 450mA
V
IH
V+ = 4.0V to 16.0V
V+ = 4.0V to 11.0V
I
LOAD
= 0mA to 750mA
V+ = 9.0V, I
LOAD
= 300mA
V
IL
V+ = 12V, I
LOAD
= 750mA
ABSOLUTE MAXIMUM RATINGS
V+ = 6.0V to 11.0V;
0mA < I
LOAD
< 450mA for MAX750AC,
0mA < I
LOAD
< 450mA for MAX750AE,
0mA < I
LOAD
< 300mA for MAX750AM
V+ = 6.0V to 16.0V;
0mA < I
LOAD
< 450mA for MAX758AC/AE,
0mA < I
LOAD
< 350mA for MAX758AM
V+ = 10.2V to 16.0V,
0mA < I
LOAD
< 750mA
Shutdown Supply
Current (Note 2)
Shutdown Input
Leakage Current
MAX750A
MIN
TYP
MAX
MAX758A
MIN
TYP
MAX
6.0
100.0
2.0
0.15
4.0
16.0
0.0005
90
0.25
87
1.0
1.7
3.0
1.5
4.75
5.00
5.25
4.75
5.00
5.25
MAX750A/MAX758A
Adjustable, Step-Down,
Current-Mode PWM Regulators
_______________________________________________________________________________________
3
Note 1:
Output voltage tolerance over temperature is 4.5% plus the tolerances of R3 and R4 in Figure 3.
Note 2:
The standby current typically settles to 25A (over temperature) within 2 seconds; however, to decrease test time, the part
is guaranteed at a 100A maximum value.
PARAMETER
MAX758A
MIN
TYP
MAX
MAX750A
MIN
TYP
MAX
UNITS
3.75
4.00
3.5
0.5
1.0
1.15
1.22
1.30
50
130
160
190
7500
3.75
4.00
Undervoltage
Lockout
3.5
V
LX On Resistance
0.5
LX Leakage Current
1.0
A
Reference Voltage
1.15
1.22
1.30
V
Reference Drift
50
ppm/C
Oscillator Frequency
kHz
Compensation Pin
Impedance
7500
CONDITIONS
V+ rising
V+ falling
I
LX
= 500mA
T
A
= +25C
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 3, V+ = 9V for the MAX750A, V+ = 12V for the MAX758A, V
OUT
= 5V, R2 = 40.20k
, R3 = 13.0k
, I
LOAD
= 0mA,
T
A
= T
MIN
to T
MAX
, unless otherwise noted.)
__________________________________________Typical Operating Characteristics
(Circuit of Figure 3, V
OUT
= 5V, T
A
= +25C, unless otherwise noted.)
100
60
0
600
MAX750A
EFFICIENCY vs. OUTPUT CURRENT
70
MAX750A/58A-1
OUTPUT CURRENT (mA)
EFFICIENCY (%)
200
400
90
80
800
1000
V+ = 5.5V
V+ = 7V
V+ = 9V
V+ = 11V
(NOTES 3, 6)
100
60
0
600
MAX758A
EFFICIENCY vs. OUTPUT CURRENT
70
MAX750A/58A-2
OUTPUT CURRENT (mA)
EFFICIENCY (%)
200
400
90
80
800
1000
V+ = 6V
V+ = 8V
V+ = 12V
V+ = 16V
(NOTES 3, 6)
130
170
210
MAX750A/MAX758A
Adjustable, Step-Down,
Current-Mode PWM Regulators
4
_______________________________________________________________________________________
0
0
MAX758A
PEAK INDUCTOR CURRENT
vs. OUTPUT CURRENT
200
1000
MAX1750A/58A-4
OUTPUT CURRENT (mA)
PEAK INDUCTOR CURRENT (mA)
600
400
800
100 200 300 400 500 600 700 800
V+ = 6.6V
V+ 8.0V TO 16.0V
L1 = 100H
C4 = 300F
0
0
MAX758A
PEAK INDUCTOR CURRENT
vs. OUTPUT CURRENT
100
500
MAX1750A/58A-5
OUTPUT CURRENT (mA)
PEAK INDUCTOR CURRENT (mA)
300
200
400
100
150
200
250
300
L1 = 18H
C4 = 1000F
600
700
50
V+ = 10.2V
V+ = 8.0V
V+ = 6.6V
V+ = 6.0V
150
4
OSCILLATOR FREQUENCY
vs. SUPPLY VOLTAGE
160
200
MAX1750A/58A-6
SUPPLY VOLTAGE (V)
OSCILLATOR FREQUENCY (kHz)
180
170
190
8
10
12
14
16
210
220
6
MAX750A
MAX758A
(NOTE 3)
0
0
MAX758A
NO-LOAD SUPPLY CURRENT vs. SUPPLY VOLTAGE
0.5
2.5
MAX1750A/58A-7
SUPPLY VOLTAGE (V)
NO-LOAD SUPPLY CURRENT (mA)
1.5
1.0
2.0
4
6
8
10
14
3.0
2
12
16
UNDERVOLTAGE
LOCKOUT V+ FALLING
(OPERATION ENDS)
UNDERVOLTAGE
LOCKOUT V+ RISING
(OPERATION BEGINS)
(NOTES 3, 5)
2.0
0
-60
60
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
0.5
MAX750A/58A-8
TEMPERATURE (C)
NO-LOAD SUPPLY CURRENT (mA)
-20
20
1.5
1.0
100
140
2.5
2.0
-40
0
40
80
120
MAX750A, V+ = 9.0V
MAX758A, V+ = 12.0V
(NOTES 4, 5)
8
0
-60
60
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
2
MAX750A/58A-9
TEMPERATURE (C)
SHUTDOWN SUPPLY CURRENT (
A)
-20
20
6
4
100
140
10
12
-40
0
40
80
120
14
16
18
20
MAX758A ONLY, V+ = 16V
MAX758A ONLY, V+ = 12V
V+ = 9V
V+ = 6V
(NOTES 4, 5)
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 3, V
OUT
= 5V, T
A
= +25C, unless otherwise noted.)
TEMPERATURE (C)
OSCILLATOR FREQUENCY (kHz)
MAX750A
OSCILLATOR FREQUENCY vs. TEMPERATURE
-60
20 40
80
120
-40 -20
0
60
100
140
240
200
180
160
220
0
140
V+ = 9.0V
V+ = 7.0V
(NOTE 4)
V+ = 5.5V
V+ = 11.0V
200
180
170
160
TEMPERATURE (C)
OSCILLATOR FREQUENCY (kHz)
MAX758A
OSCILLATOR FREQUENCY vs. TEMPERATURE
190
140
-60
20
40
80
120
-40 -20
0
60
100
140
150
130
120
V+ = 6.0V
V+ = 16.0V
V+ = 12.0V
V+ = 9.0V
(NOTE 4)
MAX750A/MAX758A
Adjustable, Step-Down,
Current-Mode PWM Regulators
_______________________________________________________________________________________
5
800
4
16
MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE
1000
MAX750A/58A-10
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
8
12
1400
1200
6
10
14
MAX750A
MAX758A
(NOTES 3, 6)
200
4
16
MAXIMUM OUTPUT CURRENT
vs. SUPPLY VOLTAGE, R1 OMITTED
1000
MAX750A/58A-11
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
8
12
1400
1200
6
10
14
600
800
400
MAX750A
MAX758A
(NOTES 3, 6)
MAX758A
SWITCHING WAVEFORMS
CONTINUOUS CONDUCTION
2
s/div
A: SWITCH VOLTAGE (LX PIN), 5V/div, 0V TO +12V
B: INDUCTOR CURRENT, 200mA/div
C: OUTPUT VOLTAGE RIPPLE, 50mV/div
COUT = 390
F, V+ = 12V, IOUT = 150mA
MAX758A
SWITCHING WAVEFORMS
DISCONTINUOUS CONDUCTION
2
s/div
A: SWITCH VOLTAGE (LX PIN), 5V/div, 0V TO +12V
B: INDUCTOR CURRENT, 100mA/div
C: OUTPUT VOLTAGE RIPPLE, 50mV/div
COUT = 390
F, V+ = 12V, IOUT = 20mA
12V
0V
200mA
0mA
5V
A
B
C
12V
0V
100mA
0mA
5V
A
B
C
_____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 3, V
OUT
= 5V, T
A
= +25C, unless otherwise noted.)
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