Rainbow Electronics MAX833 User Manual
19-0167; Rev 2; 6/95
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
5V/3.3V/3V/Adjustable-Output, 1A,
Step-Down, PWM, Switch-Mode DC-DC Regulators
_______________General Description
The MAX830/MAX831/MAX832/MAX833 are monolithic,
bipolar, pulse-width-modulation (PWM), switch-mode, stepdown DC-DC regulators. Each is rated at 1A. Very few
external components are needed for standard operation
because the power switch, oscillator, feedback, and control
circuitry are all on-chip. Employing a classic buck topology,
these regulators perform high-current step-down functions.
These regulators have excellent dynamic and transient
response characteristics, while featuring cycle-by-cycle current limiting to protect against overcurrent faults and shortcircuit output faults. They have a wide 8V to 30V input
range. Outputs for the MAX831/MAX832/MAX833 are fixed
at 5V/3.3V/3V, respectively. The MAX830 output is
adjustable.
Available in 16-pin SO packages, the MAX830–MAX833
have a preset 100kHz oscillator frequency. In addition,
the preset current limit and micropower shutdown can be
externally controlled. See the MAX724/MAX726 data
sheet for more applications information.
_______________________Applications
Distributed Power from High-Voltage Buses
High-Current, High-Voltage Step-Down Applications
Multiple-Output Buck Converter
___________________________Features
♦ Input Range: Up to 30V
♦ 1A On-Chip Power Switch
♦ Adjustable Output (MAX830)
Fixed Outputs: 5V (MAX831)
3.3V (MAX832)
3V (MAX833)
♦ 100kHz Switching Frequency
♦ Excellent Dynamic Characteristics
♦ Few External Components
♦ 8mAQuiescent Current
♦ 16-Pin SOPackage
♦ Evaluation Kit Available
______________Ordering Information
PART TEMP. RANGE PIN-PACKAGE
MAX830CWE 0°C to +70°C 16 Wide SO
MAX831CWE 0°C to +70°C 16 Wide SO
MAX832CWE 0°C to +70°C 16 Wide SO
MAX833CWE 0°C to +70°C 16 Wide SO
MAX830–MAX833
__________Typical Operating Circuit
INPUT
8V TO 30V
100µF
10k
0.047µF
* CoilCraft DO3316-104
V
V
IN
C
MAX831
GND
V
SENSE
SW
100µH*
MBR350
STEP-DOWN CONVERTER
________________________________________________________________
OUTPUT
5V AT 1A
470µF
__________________Pin Configuration
TOP VIEW
V
IN
1
V
2
IN
V
IN
3
V
IN
MAX830
4
GND
I
GND
(FB) SENSE
( ) ARE FOR MAX830
* THIS THERMAL RESISTANCE NUMBER IS WITH THE DEVICE WELL MOUNTED
ON 1 oz. COPPER WITH THERMAL PASTE BETWEEN THE IC AND THE
UNDERLYING GROUND PLANE. LOWER THERMAL RESISTANCE IS POSSIBLE
(SEE APPLICATIONS SECTION).
MAX831
5
MAX832
MAX833
6
LIM
7
8
Wide SO
Tj (
= +125°C, θ
MAX)
Maxim Integrated Products
Call toll free 1-800-998-8800 for free samples or literature.
jA =
V
SW
16
V
15
SW
V
14
SW
V
13
SW
GND
12
V
11
C
GND
10
SHUT
9
+55°C/W*
1
5V/3.3V/3V/Adjustable-Output, 1A,
Step-Down, PWM, Switch-Mode DC-DC Regulators
ABSOLUTE MAXIMUM RATINGS
Input Voltage..................................................40V
Switch Voltage with Respect to Input Voltage................50V
Switch Voltage with Respect to GND
negative) (Note 1).....................................20V
(V
SW
FB/SENSE Voltage ...................................-0.3V, +10V
SHUT Voltage (not to exceed V
Note 1: Do not exceed switch-to-input voltage limitation.
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.
)............................30V
IN
ELECTRICAL CHARACTERISTICS
(VIN= 25V, TA= T
MAX830–MAX833
MAX830–MAX833
Input Supply Voltage Range 830V
Switch-On Voltage (Note 2)
Switch-Off Leakage
Supply Current (Note 3)
Minimum Supply Voltage (Note 5)
Switch-Current Limit (Note 6)
Maximum Duty Cycle
Switching Frequency
Switching-Frequency Line Regulation 8V ≤ VIN≤ 30V 0.03 0.10 %/V
Error-Amplifier Voltage Gain 1V ≤ VC≤ 4V 2000 V/V
Error-Amplifier Transconductance
Error-Amplifier Source Current
Error-Amplifier Sink Current
to T
MIN
PARAMETER CONDITIONS
, unless otherwise noted. Typical values are at TA = +25°C.)
MAX
ISW= 0.2A 1.1
ISW= 1A 1.4
VIN= 25V, VSW= 0V 150
VIN= 30V, VSW= 0V 250
VIN≤ 30V, V
MAX833) or V
V
= 0.1V (Note 4) 140 500 µA
SHUT
Normal mode
Startup mode 3.5 4.8
I
open
LIM
R
= 10kΩ (Note 7)
LIM
R
= 7kΩ (Note 7)
LIM
VFBor V
SENSE
VFB= 2.0V (MAX830) or
= 2.0V
V
SENSE
(MAX831/832/833)
VFB= 2.5V (MAX830) or
= 5.5V
V
SENSE
(MAX831/832/833)
= 5.5V (MAX831/MAX832/
SENSE
= 2.5V (MAX830)
FB
= 0V (Note 6)
Voltage (forced)..........................................5.5V
I
LIM
Operating Temperature Range.....................0°C to +70°C
Junction Temperature Range.....................0°C to +125°C
Storage Temperature Range ...................-65°C to +160°C
Lead Temperature (soldering, 10sec)....................+300°C
MIN TYP MAX UNITS
V
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
TA= +25°C
811
7.3 8.0
1.2 1.7 2.2
1.2
0.8
85 90 %
90 100 110
85 120
20
3000 5000 9000 µmho
100 140 225
0.6 1.0 1.7 mATA= +25°C
µA
mA
V
A
kHz
µATA= +25°C
2 _______________________________________________________________________________________
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