欧美成人免费电影,国产欧美一区二区三区精品酒店,精品国产a毛片,色网在线免费观看

參數資料
型號: MC34270FB
廠商: MOTOROLA INC
元件分類: 穩壓器
英文描述: Single Output LDO, 250mA, Fixed(3.0V), Low Noise, Fast Transient Response 5-SOT-23 -40 to 85
中文描述: 0.5 A DUAL SWITCHING CONTROLLER, 700 kHz SWITCHING FREQ-MAX, PQFP32
封裝: PLASTIC, QFP-32
文件頁數: 6/12頁
文件大?。?/td> 364K
代理商: MC34270FB
MC34270 MC34271
6
MOTOROLA ANALOG IC DEVICE DATA
VDD LEVEL (V)
0
0
1000
R
F
Figure 9. Frequency versus Timing
TIMING RESISTANCE (k
, s)
Figure 10. VA, Vref versus VDD
100
10
5.0
4.0
3.0
2.0
1.0
0
100
1000
1.0
2.0
3.0
4.0
5.0
6.0
VDD = 6.0 V
TA = 25
°
C
RT = 169 k
TA = 25
°
C
VA
Vref
OPERATING DESCRIPTION
The MC34270 and MC34271 series are monolithic, fixed
frequency power switching regulators specifically designed
for dc to dc converter and battery powered applications.
These devices operate as fixed frequency, voltage mode
regulators containing all the active functions required to
directly implement step–up, step–down and voltage inverting
converters with a minimum number of external components.
Potential markets include battery powered, handheld,
automotive, computer, industrial and cost sensitive consumer
products. A description of each section is given below with
the representative block diagram shown in Figure 9.
Oscillator
The oscillator frequency is programmed by resistor RT.
The charge to discharge ratio is controlled to yield a 95%
maximum duty cycle at the switch outputs. During the fall
time of the internal sawtooth waveform, the oscillator
generates an internal blanking pulse that holds the inverting
input of the AND gates high, disabling the output switching
MOSFETs. The internal sawtooth waveform has a nominal
peak voltage of 3.3 V and a valley voltage of 1.7 V.
Pulse Width Modulators
Both pulse width modulators consist of a comparator with
the oscillator ramp voltage applied to the noninverting input,
while the error amplifier output is applied to the inverting
input. A third input to the comparator has a 0.5 mA typical
current source that can be used to implement soft start.
Output switch conduction is initiated when the ramp
waveform is discharged to the valley voltage. As the ramp
voltage increases to a voltage that exceeds the error
amplifier output, the latch resets, terminating output
MOSFET conduction for the duration of the oscillator ramp.
This PWM/latch combination prevents multiple output pulses
during a given oscillator cycle.
Each PWM circuit is enabled by a logic input. When
disabled, the entire block is turned off, drawing only leakage
current from the power source. Shared circuits, like the
reference and oscillator, can be activated by either EN1
or EN2.
Circuit #1 has an ELD output which may be used to drive
an LCD or backlight. Its output frequency is the oscillator
frequency divided by 1024.
Error Amplifiers and Reference
Each error amplifier is provided with access to both
inverting and noninverting inputs, and the output. The Error
Amplifiers’ Common Mode Input Range is 0 to 2.5 V. The
amplifiers have a minimum dc voltage gain of 60 dB. The
1.25 V reference has an accuracy of
±
4.0% at room
temperature.
External loop compensation is required for converter
stability. A simple low–pass filter is formed by connecting a
resistive divider from the output to the error amplifier
inverting input, and a series resistor–capacitor from the error
amplifier output also to the to the inverting input. The step
down converter is easiest to compensate for stability. The
step–up and voltage inverting configurations, when operated
as continuous conduction boost or flyback converters, are
more difficult to compensate, and may require a lower loop
design bandwidth.
MOSFET Switch Outputs
The output MOSFETs are designed to switch a maximum
of 60 V, with a peak drain current capability of 500 mA. In
circuit #1 an additional DRV1 output is provided for
interfacing with an external MOSFET.The gates of the
MOSFETs are held low when the circuit is disabled.
Auxiliary Output Voltages
Output voltages V0 through V4 are provided for use as
references or bias voltages. V0 is the circuit #2 output
voltage, when an internal FET switch is activated. The other
auxiliary output voltages are proportional to VB. The
amplifiers for V1 and V2 are powered from V0, while the
amplifiers for V3 and V4 are powered from VDD.
相關PDF資料
PDF描述
MC3447 BIDIRECTIONAL INSTRUMENTATION BUS(GPIB) TRANSCEIVER
MC3447P3 BIDIRECTIONAL INSTRUMENTATION BUS(GPIB) TRANSCEIVER
MC3447P BIDIRECTIONAL INSTRUMENTATION BUS(GPIB) TRANSCEIVER
MC3447L BIDIRECTIONAL INSTRUMENTATION BUS(GPIB) TRANSCEIVER
MC3448AL QUAD THREE-STATE BUS TRANSCEIVER WITH TERMINATION NETWORKS
相關代理商/技術參數
參數描述
MC34271FB 制造商:Rochester Electronics LLC 功能描述:- Bulk
MC34280FTB 制造商:ON Semiconductor 功能描述:
MC3430 制造商:mCube 功能描述:
MC3430P 制造商:Motorola Inc 功能描述:
MC34311 制造商:SPC Multicomp 功能描述:HEADER R/ANGLE 2WAY 制造商:SPC Multicomp 功能描述:HEADER, R/ANGLE, 2WAY 制造商:SPC Multicomp 功能描述:WIRE-BOARD CONNECTOR, RCPT, 2POS, 4.2MM; Series:2261(5561); Pitch Spacing:4.2mm; Contact Termination:Through Hole Right Angle; No. of Contacts:2; No. of Rows:2; Connector Mounting:PCB; Gender:Receptacle; Contact Material:Copper Alloy;RoHS Compliant: Yes
主站蜘蛛池模板: 青阳县| 蒲城县| 建湖县| 长泰县| 石林| 虹口区| 团风县| 临颍县| 会东县| 天等县| 兴化市| 双柏县| 广汉市| 绩溪县| 防城港市| 油尖旺区| 长沙市| 城市| 蓝田县| 喀喇沁旗| 芒康县| 辽阳市| 东源县| 岗巴县| 淮南市| 濮阳市| 营山县| 怀集县| 合阳县| 宜都市| 桃园县| 财经| 屏东市| 承德市| 搜索| 贵港市| 崇文区| 隆回县| 高碑店市| 桐柏县| 稻城县|