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부품번호 | LD7120 기능 |
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기능 | Single Synchronous Buck PWM Controller | ||
제조업체 | Leadtrend | ||
로고 | |||
LD7120
2/21/2005
Single Synchronous Buck PWM Controller
General Description
The LD7120 is a single PWM controller designed to drive
N-channel MOSFET in a synchronous buck topology. The IC
integrates the controller, output adjustment, monitoring, and
protection functions in a single 8-pin package.
The LD7120 provides simple, single feedback loop, voltage
mode controller with fast transient response. Internal 0.8V
temperature-compensated reference voltage is designed to
meet low output voltage for further applications. A fixed
300KHz frequency oscillator reduces design complexity,
while balancing typical application cost and efficiency.
The LD7120 features over current protection. The output
current is monitored by sensing the voltage drop across the
MOSFET RDS(ON), which eliminates the need for a current
sensing resistor.
Features
• Operates from 5V
• Drives Two N-channel MOSFETs
• Fixed 300KHz Constant Switching Frequency
• Full 0~100% Duty-cycle
• Programmable Over Current Protection
• Internal Soft-start
• Fast Transient Response
• Under-voltage Lockout
Applications
• Motherboard
• Graphic Cards
• 5V Input DC/DC Converter
• Memory Supplies
• Cable Modem, Set Top Box and DSL Modems
• DSP and Core Communications Processor Supplies
Typical Application
Vin= 5V
R3
6.19K
R2
10K
C10
8.2nF
R1
1K
C12
0.1uF
C7
1uF
C5 C6
330uF 330uF
5
7
C9
470pF
6
VCC
BOOT
OCSET
UGATE
LD7120
PHASE
1
2
8
FB
4
LGATE
GND
3
Q1
Q2
C8
1uF
D1
CH551H-30
C1
0.1uF
L1 2uH
R6
NC
R4
2.15K
C13
NC
Leadtrend Technology Corporation
LD7120-DS-05 February 2005
R5
62 ohm
C11
18nF
1
R7
0 ohm
Vout
C2 C3 C4
470uF 470uF 0.1uF
Free Datasheet http://www.Datasheet4U.com
Electrical Characteristics
(TA = +25oC unless otherwise stated, VCC=5.0V)
PARAMETER
CONDITIONS
Vcc Supply Current
Nominal Supply
UGATE and LGATE Open
Power On Reset
Rising VCC POR Threshold
VCC POR Threshold Hysteresis
Oscillator
Frequency
Vcc=5V
Ramp Amplitude
Reference
Reference Voltage Tolerance
Nominal Reference Voltage
Error Amplifier
DC Gain
Gain Bandwidth Product
Gate Drivers
Upper Gate Source Current
Upper Gate Sink Current
Lower Gate Source Current
Lower Gate Sink Current
Protection/Disable
OCSET Current Source
Disable Threshold
LD7120
MIN
TYP
MAX UNITS
2.0 mA
4.1 4.3 4.5 V
0.4 V
250 300 340 KHz
1.5 Vp-p
2%
0.8 V
70
10
dB
MHz
-1 A
1A
-1 A
2A
17.5
20
22.5
µA
0.8 V
Leadtrend Technology Corporation
LD7120-DS-05 February 2005
4
Free Datasheet http://www.Datasheet4U.com
4페이지 LD7120
Vin
1uF
VCC
D1
1 BOOT
2 UGATE
LD7120
8
Vcc
4
PHASE
LGATE
Q1
Cboot
0.1uF
Q2
Vout
Fig. 9
Layout Consideration
Layout is very important in high switching convert design.
There are two sets of critical components in DC/DC
converter using LD7120.The switching components are the
most critical because they switch large amount of energy,
and therefore tend to generate large amount of noise. Next
are the small signal components, which connect to sensitive
nodes, or those supplying critical bypass current and signal
coupling. Care should be taken to separate these two sets
of components and their associated grounds. Below are
some guidelines for PCB layout while using LD7120.
1. Keep the bypass capacitor 1µF very close to IC.
2. Keep output voltage feed back network, FB pin and
OCSET pin related components (small signal
components) very close to IC.
3. Signal ground plane of FB and OCSET pin (small signal
components) should be connected to the power ground
plane with a via or only one point to minimize the effect
of power ground currents.
4. Switching node such as BOOT, UGATE, PHASE and
LGATE should be kept as small as possible and routed
away from FB and OCSET pin.
5. The PCB traces carrying discontinuous currents and
any high current path should be made as short and
wide as possible.
6. If possible, a multi-layer PCB is recommended. Please
refer to the EV kit of LD7120 for a PCB layout example.
Leadtrend Technology Corporation
LD7120-DS-05 February 2005
7
Free Datasheet http://www.Datasheet4U.com
7페이지 | |||
구 성 | 총 8 페이지수 | ||
다운로드 | [ LD7120.PDF 데이터시트 ] |
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구매 문의 | 일반 IC 문의 : 샘플 및 소량 구매 ----------------------------------------------------------------------- IGBT, TR 모듈, SCR 및 다이오드 모듈을 포함한 광범위한 전력 반도체를 판매합니다. 전력 반도체 전문업체 상호 : 아이지 인터내셔날 사이트 방문 : [ 홈페이지 ] [ 블로그 1 ] [ 블로그 2 ] |
부품번호 | 상세설명 및 기능 | 제조사 |
LD7120 | Single Synchronous Buck PWM Controller | Leadtrend |
LD7120A | Single Synchronous Buck PWM Controller | Leadtrend |
DataSheet.kr | 2020 | 연락처 | 링크모음 | 검색 | 사이트맵 |