ST730 [STMICROELECTRONICS]
5V STEP-DOWN, CURRENT-MODE PWM DC-DC CONVERTERS; 5V降压，电流模式PWM DC -DC转换器
| 型号： | ST730 |
| 厂家： | 
ST |
| 描述： | 5V STEP-DOWN, CURRENT-MODE PWM DC-DC CONVERTERS |
| 文件： | 总9页 (文件大小：262K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ST730A
5V STEP-DOWN,
CURRENT-MODE PWM DC-DC CONVERTERS
■
■
UP TO 450mA LOAD CURRENTS
200kHz HIGH-FREQUENCY
CURRENT-MODE PWM
■
■
85% TO 96% EFFICIENCIES
33µH OR 100µH PRE-SELECTED
INDUCTOR VALUE, NO COMPONENT
DESIGN REQUIRED
■
■
■
■
0.8mA QUIESCENT CURRENT
0.3µA SHUTDOWN SUPPLY CURRENT
ADJUSTABLE OUTPUT VOLTAGE
OVERCURRENT, SOFT-START AND
UNDERVOLTAGE LOCKOUT PROTECTION
CYCLE-BY-CYCLE CURRENT LIMITING
PACKAGE AVAILABLE: DIP-8 AND SO-8
DIP-8
SO-8
precise output regulation and excellent transient
responses. Output voltage accuracy is
guaranteed to be ±5% over line, load, and
temperature varations.
■
■
Fixed-frequency switching and absence of
subharmonic ruipple allows easy filtering of output
ripple and noise, as well as the use of small
external components. This regulators require only
DESCRIPTION
The ST730A is a 5V output CMOS, step-down
switching regulator. The ST730A accepts inputs
between 5.2V and 11V and delivers 450mA.
Typical efficiencies are 85% to 96%.
Quiescent supply current is 0.8mA and only 0.3µA
in shutdown mode. The output does not exhibit
frequency over this specified range. Pulse-width
modulation (PWM) current-mode control provides
a
single inductor value to work in most
applications, so no inductor design is necessary.
Typical applications are: Cellular phones & radios,
portable Instruments, Portable Communications
Equipments and Computer Peripherals.
SCHEMATIC DIAGRAM
January 2003
1/9
ST730A
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter²
Value
Unit
V
DC Input Voltage
-0.3 to 12
V
V
CC
V
Switch Pin Voltage
-0.3 to (V + 0.3)
LX
CC
V
Shutdown Voltage (SHDN)
-0.3 to (V + 0.3)
V
SHDN
CC
V ,V
Soft Start (SS) and Compensation Capacitor (CC) Pins Voltage
Switching Peak Current
-0.3 to (V + 0.3)
V
S
C
CC
I
2
A
LX
I
Reference Current
2.5
mA
REF
Continuous Power Dissipation at T =70°C (DIP-8)
550
344
mW
mW
A
P
TOT
(SO-8)
T
Storage Temperature Range
-40 to +150
°C
stg
Operating Junction Temperature Range (C series)
(B series)
0 to +70
-40 to +85
°C
°C
T
op
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is
not implied.
THERMAL DATA
Symbol
Parameter
SO-8
DIP-8
Unit
R
Thermal Resistance Junction-ambient (*)
160
100
°C/W
thj-amb
(*) This value depends from thermal design of PCB on which the device is mounted.
ORDERING CODES
TYPE
DIP8
SO-8
SO-8 (T&R)
ST730AB
ST730AC
ST730ABN
ST730ACN
ST730ABD
ST730ACD
ST730ABD-TR
ST730ACD-TR
2/9
ST730A
CONNECTION DIAGRAM (top view)
PIN DESCRIPTION
Pin N°
Symbol
Name and Function
Shutdown control (active low): If connected to GND the IC is in shutdown.
1
SHDN
Connect to V for normal operation (ON MODE)
CC
2
3
4
5
REF
SS
Reference Output Voltage: (1.25V): Bypass to GND with a capacitor that does not
exceed 47nF
Soft Start: a capacitor between SS and GND provides soft-start and short-circuit
protections.
CC
Compensation Capacitor Input: externally compensates the outer (voltage)
feedback loop. Connect to OUT with 330pF capacitor
OUT
Output Voltage Sense Input: provides regulation of feedback sensing. Connect to
5V output.
6
7
8
GND
LX
Ground
Switch Output. Drain of internal P-Channel Power MOSFET
V
Supply Voltage Input. Bypass to GND with 1µF ceramic capacitance and large
value electrolytic capacitor in parallel. The 1µF capacitor must be as close as
CC
possible to the GND and V pins
CC
3/9
ST730A
ELECTRICAL CHARACTERISTICS (V =5V, I = 0mA, T = T
to T
, unless otherwise specified.)
MAX
CC
O
A
MIN
Symbol
Parameter
Input Voltage
Test Conditions
Min.
4
Typ.
Max.
11
Unit
V
V
CC
V
Output Voltage
Line Regulation
Load Regulatio
Power Efficency
Supply Current
V
V
= 6 to 11V
I =0 to 450mA
O
4.75
5
5.25
V
O
CC
∆V
∆V
η
= 5.2 to 11V
0.15
0.005
92
%/V
%/mA
%
O
O
CC
I
I
= 0 to 450mA
=300mA
O
O
I
ON Mode
OFF Mode, SHDN=0
0.8
0.3
2.5
100
mA
µA
SUPPLY
V
SHDN Input High Threshold
SHDN Input Low Threshold
2
V
V
IH
V
0.25
1
IL
SHDN
I
Shutdown Input Leakage
Current
µA
V
Under Voltage Lockout
LX On Resistance
LX Leakage Current
Reference Voltage
V
Falling
2.7
0.5
1
3
V
Ω
LOCK
CC
R
I =500mA
LX
DS(on)
I
V
= 12V
V = 0V
LX
µA
LX
CC
V
T = 25°C
1.17
1.24
50
1.31
V
REF
A
∆V
Temperature Reference
Drift
ppm/°C
REF
f
Switching Frequency
B series
C series
180
160
200
220
280
OSC
KHz
R
Compensation Pin
Impedance
7500
Ω
C
TYPICAL APPLICATION CIRCUIT
4/9
ST730A
TYPICAL PERFORMANCE CHARACTERISTICS (unless otherwise specified T = 25°C
j
Figure 1 : Efficency vs Output Current
Figure 4 : Oscillator Frequency vs Input Voltage
Figure 2 : Supply Current vs Temperature
Figure 5 : Peak Inductor Current vs Output
Current
Figure 3 : Oscillator Frequency vs Temperature
Figure 6 : Output Voltage vs Output Current
5/9
ST730A
Figure 7 : Switching Waveforms, Continuous
Figure 9 : Line Transient
Conduction
V =6V to 11V, I =300mA
I
O
Figure 8 : Switching Waveforms, Discontinuous
Figure 10 : Load Transient
Conduction
V =6V to 11V, I =300mA
I
O
6/9
ST730A
Plastic DIP-8 MECHANICAL DATA
mm.
inch
TYP.
0.130
DIM.
MIN.
TYP
MAX.
MIN.
MAX.
A
a1
B
3.3
0.7
1.39
0.91
0.028
0.055
0.036
1.65
1.04
0.065
0.041
B1
b
0.5
0.020
b1
D
E
0.38
0.5
9.8
0.015
0.020
0.386
8.8
0.346
0.100
0.300
0.300
e
2.54
7.62
7.62
e3
e4
F
7.1
4.8
0.280
0.189
I
L
3.3
0.130
Z
0.44
1.6
0.017
0.063
P001F
7/9
ST730A
SO-8 MECHANICAL DATA
mm.
inch
TYP.
DIM.
MIN.
TYP
MAX.
MIN.
MAX.
A
A1
A2
B
1.35
1.75
0.053
0.069
0.10
1.10
0.33
0.19
4.80
3.80
0.25
1.65
0.51
0.25
5.00
4.00
0.04
0.010
0.065
0.020
0.010
0.197
0.157
0.043
0.013
0.007
0.189
0.150
C
D
E
e
1.27
0.050
H
5.80
0.25
0.40
6.20
0.50
1.27
0.228
0.010
0.016
0.244
0.020
0.050
h
L
k
˚ (max.)
8
ddd
0.1
0.04
0016023/C
8/9
ST730A
ormation furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
nsequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
entioned in this publication are subject to change without notice. This publication supersedes and replaces all information
eviously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
stems without express written approval of STMicroelectronics.
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