1.8V Operate PWM control Step-Up / Flyback switching regulator IC - New Japan Radio
Description
NJU7677
1.
8V Operate PWM control Step-Up / Flyback switching regulator IC
■ GENERAL DESCRIPTION
The NJU7677 is a high-speed switching regulator control IC for PWM control step-up and fly-back converter that operates from 1.
8V.
It incorporates a totem pole driver output, which can directly drive an external MOS-FET.
The NJU7677 also has a soft-start function, dead time control and timer latch for short circuit protection and their times are all adjustable with external parts.
It is available in a small and thin 8-lead MSOP (TVSP) package.
It is suitable for battery powered applications.
■ PACKAGE OUTLINE
NJU7677RB1 (MSOP8 (TVSP8))
■ FEATURES
● PWM switching control
● Operating Voltage
1.
8V to 7V
● Wide Oscillator Range 300kHz to 1MHz
● Maximum Duty Cycle 90% typ.
● Quiescent Current ● Soft-Start Function
600µA typ.
Internal : 4ms typ.
or adjustable
● Dead Time Control
● Timer Latch for Short Circuit Protection
● C-MOS Technology
● Package Outline
NJU7677RB1 : MSOP8 (TVSP8)*
*MEET JEDEC MO-187-DA / THIN TYPE
■ PIN CONFIGURATION
PIN FUNCTION 1 8 1.
V+
2
7
2.
FB 3.
IN-
3 6 4.
SCP 5.
DTC
4 5 6.
RT
7.
GND
NJU7677RB1
8.
OUT
Ver.
2012-08-03
-1-
NJU7677
■ BLOCK DIAGRAM
FB
IN-
1V Vref
V+
ER⋅AMP
Soft Start
Latch
UVLO
SCP
1V
2µA SCP
2kΩ 1V
0.
5 RT
A
DTC
0.
65V 0.
15V
OSC 0.
5V
PW M
Buffer
OUT
0.
6V
RT RT
GND
-2-
Ver.
2012-08-03
NJU7677
■ ABSOLUTE MAXIMUM RATINGS
PARAMETER
Supply Voltage Output Pin Current Power Dissipation Operating Temperature Range Storage Temperature Range
SYMBOL V+
IO PD TOPR TSTG
MAXIMUM RATINGS
+8 ±50 320 -40 to +85 -40 to +125
(Ta=25°C)
UNIT
V mA mW °C °C
■ RECOMMENDED OPERATING CONDITIONS
PARAMETER
Operating Voltage Oscillator Timing Resistor Oscillation Frequency
SYMBOL V+
RT fOSC
MIN.
1.
8 30 300
(Ta=25°C)
TYP.
MAX.
UNIT
–7V 47 120 kΩ 700 1,000 kHz
■ ELECTRICAL CHARACTERISTICS
PARAMETER
SYMBOL
TEST CONDITION
Under Voltage Lockout Block ON Threshold Voltage OFF Threshold Voltage Hysteresis Vol...
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