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GM3843A の電気的特性と機能

GM3843AのメーカーはGammaです、この部品の機能は「(GM3842A - GM3845A) HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS」です。


製品の詳細 ( Datasheet PDF )

部品番号 GM3843A
部品説明 (GM3842A - GM3845A) HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS
メーカ Gamma
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GM3843A Datasheet, GM3843A PDF,ピン配置, 機能
www.DataSheet4U.com
Description
GM384XA series is high performance with fixed-frequency
current mode PWM controllers. They are specially de-
signed for off-Line and DC-to-DC converter applications.
They require minimal external components to precisely tai-
lor performance in a wide variety of applications.
GM384XA series includes a trimmed oscillator for precise
duty cycle control, a temperature-compensated reference,
high gain error amplifier, a current-sensing comparator,
and a high-current totem pole output for driving a power
MOSFET.
On-chip protection features include undervoltage lockouts
with hysteresis for both input and reference, cycle-by-cycle
current limiting, programmable output deadtime, and a
latch for single pulse metering. All these are in a simple
DIP-8 or SOP-8 package!
GM3842A and GM3844A have UVLO thresholds of 16V
(on)/10V(off); GM3843A and GM3845A have UVLO thresh-
olds of 8.4V (on)/ 7.6V (off). GM3842A and GM3843A oper-
ate within 100% duty cycle; GM3844A and GM3845A oper-
ate within 50% duty cycle.
Features
Low Start-Up and Operating Current
Automatic Feed Forward Compensation
Current Mode Operating Frequency up to
500kHz
Trimmed Oscillator Discharge Current for
Precise Duty Cycle Control
Latching PWM for Cycle-By-Cycle Current
Limiting
Undervoltage Lockout with Hysteresis
High Current Totem Pole Output
The GM384XA Have Start-up Current 0.17mA
SIMPLIFIED BLOCK DIAGRAM
Vref 8
RT/ CT 4
Voltage Feedback Input 2
Output Compensation 1
5.0V
REFERENCE
R
R VREF
Undervoltage
LOCKOUT
VCC
7
VCC
Undervoltage
LOCKOUT
OSCILLATOR
Error
Amplifier
+
-
Latching
PWM
5
GND
7 VC
6 Output
5 Power Ground
3 Current Sense Input
www.gammamicro.com 1

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GM3843A pdf, ピン配列
ABSOLUTE MAXIMUM RATINGS
PARAMETER
SYMBOL
Supply Voltage (low impedance source)
Output Current, Source or Sink *
Input Voltage (analog inputs pins 2)
Maximum Power Dissipation (TA= 25°C)
Error Amp Output Sink Current
Storage Temperature Range
Lead Temperature (soldering 5 sec.)
VCC
IO
VI
PD
ISINK(E.A)
Tstg
TL
* Note: Maximum Package Power Dissipation Limits must be observed.
VALUE
30
±1.0
- 0.3 to + 5.5
1.0
10
- 65 to + 150
260
UNIT
V
A
V
W
mA
°C
°C
PACKAGE PIN DESCRIPTION
PIN lead
1
2
3
4
5
6
7
8
FUNCTION
COMP
FUNCTION
This pin is Error Amplifier output and is made available for loop compensation.
VFB
This is the inverting input of the Error Amplifier. It is normally connected to the
switching power supply output through a resistor divider.
ISENSE
A voltage proportional to inductor current connected to this input. The PWM
uses this information to terminate the output switch conduction.
RT/ CT
GND
Oscillator frequency and maximum Output cycle are programmed by connecting
resistor RT to VREF and capacitor CT to ground.
This pin is the combined control circuitry and power ground.
Output
This output directly drives the gate of a power MOSFET. Peak current up to 1.0A
are sourced and sunk by this pin.
VCC
VREF
This pin is the positive supply of the control integrated circuit (IC)
This is the reference output. It provides charging current for capacitor CT
through resistor RT.
3


3Pages


GM3843A 電子部品, 半導体
ELECTRICAL CHARACTERISTICS (Continued)
(TA = 0°C to 70°C, *VCC=15V, CT=3.3nF, RT=10kW, unless otherwise specified )
CHARACTERISTICS
SYMBOL
TEST CONDITIONS
MIN
PWM Section
Maximum Duty Cycle
Minimum Duty Cycle
Total Standby Current
Start-Up Current
Operating Supply Current
Zener Voltage
D(MAX)
D(MIN)
GM3842A, GM3843A
GM3844A, GM3845A
IST
ICC(OPR)
VZ
GM3842A/ 43A/ 44A/ 45A
VPIN3= VPIN2=0V
ICC= 25mA
95
47
30
* Adjust VCC above the Startup threshold before setting to 15 V.
Note1: Parameter measured at trip point of latch with VPIN2 = 0.
Note2: Gain defined as A=DVPIN1 / DVPIN3 ; 0 VPIN3 0.8V
Note3: These parameters, although guaranteed, are not 100% tested in production
TYP MAX UNIT
97
48
0.17
13
38
100
50
0
0.3
17
%
%
%
mA
mA
V
TYPICAL PERFORMANCE CHARACTERISTICS
RT
(KW)
50
CT= 1nF
20
CT= 1000pF
CT= 200pF
CT= 500pF
10
CT= 5nF
5
CT= 10pF
CT= 2nF
2 VCC= 15V
1 TA=25°C
10 20 30
50
100 200 300 500
fosc
(kHz)
Figure 1. Timing Resistor vs. Oscillator Frequency
%
VCC= 15V
TA=25°C
50
30
CT= 5nF
20
CT= 10pF
10 CT= 2nF
CT= 1nF
5
CT= 500pF
CT= 200pF
CT= 1000pF
3
2
1
10 20 30 50
100 200 300 500
fosc
(kHz)
Figure 2. Output Dead-Time vs. Oscillator Frequency
6

6 Page



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部品番号部品説明メーカ
GM3843A

(GM3842A - GM3845A) HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS

Gamma
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