|
|
PDF MAX738AEWE Data sheet ( Hoja de datos )
| Número de pieza | MAX738AEWE | |
| Descripción | 5V / Step-Down / Current-Mode PWM DC-DC Converters | |
| Fabricantes | Maxim Integrated | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de MAX738AEWE (archivo pdf) en la parte inferior de esta página. Total 16 Páginas | ||
|
No Preview Available !
19-0165; Rev 2; 1/96
5V, Step-Down,
Current-Mode PWM DC-DC Converters
__________________General Description
The MAX730A/MAX738A/MAX744A are 5V-output
CMOS, step-down switching regulators. The MAX738A/
MAX744A accept inputs from 6V to 16V and deliver
750mA. The MAX744A guarantees 500mA load capa-
bility for inputs above 6V and has tighter oscillator fre-
quency limits for low-noise (radio) applications. The
MAX730A accepts inputs between 5.2V and 11V and
delivers 450mA for inputs above 6V. Typical efficien-
cies are 85% to 96%. Quiescent supply current is
1.7mA and only 6µA in shutdown.
Pulse-width modulation (PWM) current-mode control
provides precise output regulation and excellent tran-
sient responses. Output voltage accuracy is guaran-
teed to be ±5% over line, load, and temperature varia-
tions. Fixed-frequency switching 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.
The MAX730A/MAX738A/MAX744A also feature cycle-
by-cycle current limiting, overcurrent limiting, undervolt-
age lockout, and programmable soft-start protection.
___________________________Applications
Portable Instruments
Cellular Phones and Radios
Personal Communicators
Distributed Power Systems
Computer Peripherals
__________Typical Operating Circuit
________________________________Features
o 750mA Load Currents (MAX738A/MAX744A)
o High-Frequency, Current-Mode PWM
o 159kHz to 212.5kHz Guaranteed Oscillator
Frequency Limits (MAX744A)
o 85% to 96% Efficiencies
o 1.7mA Quiescent Current
o 6µA Shutdown Supply Current
o Single Preselected Inductor Value,
No Component Design Required
o Overcurrent, Soft-Start, and Undervoltage
Lockout Protection
o Cycle-by-Cycle Current Limiting
o 8-Pin DIP/SO Packages (MAX730A)
_________________Ordering Information
PART
TEMP. RANGE
PIN-PACKAGE
MAX730ACPA
0°C to +70°C
8 Plastic DIP
MAX730ACSA
0°C to +70°C
8 SO
MAX730AC/D
0°C to +70°C
Dice*
MAX730AEPA -40°C to +85°C
8 Plastic DIP
MAX730AESA -40°C to +85°C
8 SO
MAX730AMJA -55°C to +125°C 8 CERDIP
Ordering Information continued at end of data sheet.
*Contact factory for dice specifications.
_________________Pin Configurations
INPUT
6V TO 16V
68µF
V+
LX
ON/OFF
MAX738A
MAX744A
SHDN
OUT
REF
SS
CC
GND
33µH
OUTPUT
5V
100µF
TOP VIEW
SHDN 1
REF 2
SS 3
CC 4
MAX730A
MAX738A
MAX744A
DIP
8 V+
7 LX
6 GND
5 OUT
Pin Configurations continued on last page.
________________________________________________________________ Maxim Integrated Products 1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800
1 page  
5V, Step-Down,
Current-Mode PWM DC-DC Converters
____________________________Typical Operating Characteristics (continued)
(Circuit of Figure 3, TA = +25°C, unless otherwise noted.)
220
210
200
190
180
170
160
150
4
OSCILLATOR FREQUENCY vs.
SUPPLY VOLTAGE
(NOTE 3)
MAX730A
MAX744A
MAX738A
6 8 10 12 14 16
SUPPLY VOLTAGE (V)
MAX738A
OSCILLATOR FREQUENCY
vs. TEMPERATURE
200
(NOTE 4)
190 V+ = 6.0V
180
170 V+ = 16.0V
160
150 V+ = 12.0V
140 V+ = 9.0V
130
120
-60 -40 -20 0 20 40 60 80 100 120 140 160
TEMPERATURE (°C)
MAX730A
OSCILLATOR FREQUENCY
vs. TEMPERATURE
240
(NOTE 4)
220 V+ = 11.0V
200
V+ = 5.5V
180
160
V+ = 7.0V
V+ = 9.0V
140
0
-60 -40 -20 0 20 40 60 80 100 120 140 160
TEMPERATURE (°C)
MAX744A
OSCILLATOR FREQUENCY
vs. TEMPERATURE
210
(NOTE 4)
200 V+ = 6.0V
V+ = 16.0V
190
V+ = 9.0V
180
V+ = 12.0V
170
-60 -40 -20 0 20 40 60 80 100 120 140 160
TEMPERATURE (°C)
Note 3: Commercial temperature range external component values in Table 3.
Note 4: Wide temperature range external component values in Table 3.
Note 5: Standby and shutdown current includes all external component leakage currents. Capacitor leakage currents dominate at TA > +85°C,
Sanyo OS-CON capacitors were used.
Note 6: Operation beyond the specifications listed in the electrical characteristics may exceed the power dissipation ratings of the device.
_______________________________________________________________________________________ 5
5 Page 
5V, Step-Down,
Current-Mode PWM DC-DC Converters
Table 2. Component Values and Suppliers
Production
Method
MAX730AC/MAX738AC/MAX744AC
Commercial Temp. Range
Inductors
Capacitors
MAX730AE/M, MAX738AE/M, MAX744AE/M
Wide Temp. Range
Inductors
Capacitors
Surface
Mount
L1 = 33µH to 100µH
Sumida (708) 956-0666
CD54-101KC (MAX730AC)
CD105-101KC
(MAX738AC/MAX744AC)
Coiltronics (407) 241-7876
CTX100 series
C3 = 68µF, 16V
C4 = 100µF, 6.3V
Matsuo (714) 969-2491
267 series
Sprague (603) 224-1961
595D/293D series
L1 = 33µH
Sumida (708) 956-0666
CD54-330N (MAX730AC)
CD105-330N
(MAX738AE/M, MAX744AE/M)
Coiltronics (407) 241-7876
CTX50 series
C3 = 68µF, 16V
C4 = 100µF, 6.3V
Matsuo (714) 969-2491
267 series
Sprague (603) 224-1961
595D/293D series
C3 = 150µF, 16V
C4 = 220µF, 10V
Miniature
Through-
Hole
L1 = 33µH to 100µH
Sumida (708) 956-0666
RCH654-101K (MAX730A)
RCH895-101K
(MAX738A/MAX744A)
C3 = 150µF, 16V
C4 = 150µF, 16V or
390µF, 6.3V
Nichicon (708) 843-7500
PL series
Low-ESR electrolytics
L1 = 33µH
Sumida (708) 956-0666
RCH654-330M (MAX730A)
RCH895-330M
(MAX738A/MAX744A)
L1 = 100µH
C3 = 150µF, 16V
C4 = 390µF, 6.3V
Sanyo (619) 661-6322
OS-CON series
Low-ESR
organic semiconductor
(Rated from -55°C to +105°C)
Mallory (317) 273-0090
THF series
C3 = 100µF, 20V
C4 = 220µF, 10V
(Rated from -55°C to +125°C)
Low-Cost
Through-
Hole
Maxim
MAXL001
100µH iron-power toroid
Renco (516) 586-5566
RL1284-100
Maxim
MAXC001
150µF, low-ESR
electrolytic
United Chemicon
(708) 843-7500
Printed Circuit Layouts
A good layout is essential for clean, stable operation.
The layouts and component placement diagrams given
in Figures 4, 5, 6, and 7 have been successfully tested
over a wide range of operating conditions. Note that the
1µF bypass capacitor (C2) must be positioned as close
to the V+ and GND pins as possible. Also, place the out-
put capacitor as close to the OUT and GND pins as pos-
sible. The traces connecting the input and output filter
capacitors and the catch diode must be short to mini-
mize inductance and capacitance. For this reason, avoid
using sockets, and solder the IC directly to the PC
board. Use an uninterrupted ground plane if possible.
Output-Ripple Filtering
A simple lowpass pi-filter (Figure 3) can be added to
the output to reduce output ripple to about 5mVp-p.
The cutoff frequency shown is 21kHz. Since the filter
inductor is in series with the circuit output, its resis-
tance should be minimized so the voltage drop across
it is not excessive.
______________________________________________________________________________________ 11
11 Page | ||
| Páginas | Total 16 Páginas | |
| PDF Descargar | [ Datasheet MAX738AEWE.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| MAX738AEWE | 5V / Step-Down / Current-Mode PWM DC-DC Converters | Maxim Integrated |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |