- 您现在的位置：买卖IC网 > PDF目录15505 > MIC3808YM (Micrel Inc)IC REG CTRLR ISO PWM CM 8-SOIC PDF资料下载
参数资料
| 型号： | MIC3808YM |
| 厂商： | Micrel Inc |
| 文件页数： | 8/11页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR ISO PWM CM 8-SOIC |
| 标准包装： | 95 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 占空比： | 50% |
| 电源电压： | 2 V ~ 14 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 管件 |
| 产品目录页面： | 1086 (CN2011-ZH PDF) |
| 其它名称： | 576-1769-5 MIC3808YM-ND |
MIC3808/3809
Functional Diagram
Micrel
Overcurrent
FB
2
3.65V
COMP
1
CS
3
Peak Current
8
V DD
Comparator
0.75V
2.2V
2.0V
Error
Comparator
0.5V
14V
V DD OK
Amplifier
Oscillator
7
OUTA
S
Q
0.8V
R
PWM
Comparator
PWM
Latch
V DD —1V
S1
1.2R
S
Q
T
Q
S2
Q
R
/Q
R
0.5V
V DD
Soft Start
R
6
OUTB
Voltage
Reference
Slope = 1V/ms
4
RC
Figure 1. MIC3808 Block Diagram
5
GND
Functional Description
The MIC3808/9 is a high-speed power supply controller with
push-pull output drive capability. MIC3808 has a higher V DD
turn-on threshold and more hysteresis between V DD turn-on
and turn-off than the MIC3809. The outputs of the controller
operate in a push-pull fashion with a guaranteed dead time
between them. A block diagram of the MIC3808/9 controller
is shown in Figure 1.
V DD and Turn-on Sequence
The oscillator and output gate drive signals are disabled
when V DD is lower than the turn on threshold. Circuitry in the
output drivers eliminates glitching or random pulsing during
the start-up sequence. The oscillator is enabled when V DD is
applied and reaches the turn-on threshold. The V DD com-
parator also turns off the internal soft-start discharge FET,
slowly bringing up the COMP pin voltage.
The V DD pin is internally clamped. As V DD approaches this
clamp voltage, the V DD current will increase over the normal
current draw of the IC. Exceeding the V DD zener shunt
voltage may cause excessive power dissipation in the
MIC3808/9.
Soft-Start
The soft start feature helps reduce surge currents at the
power supply input source. An internal current source and
capacitor ramp up from 0V to near Vdd at a typical rate of
1V/ms. The softstart feature limits the output voltage of the
error amplifier at the COMP pin. As the softstart voltage rises,
it allows the COMP pin voltage to rise, which in turn allows the
duty cycle of the output drivers to increase. The internal
softstart voltage is discharged and remains discharged dur-
ing the following conditions:
1. The V DD voltage drops below the turn-off
threshold
2. The voltage on the CS pin exceeds the
overcurrent comparator threshold
Once the internal softstart discharge FET is turned on, it
cannot be turned off until the internal softstart voltage drops
down below 0.5V. This insures a clean restart.
Oscillator
The oscillator operates at twice the switching frequency of
either OUTA or OUTB. The oscillator generates a sawtooth
waveform on the RC pin. The rising edge of the waveform is
controlled by the external resistor/capacitor combination.
The fall time is set by the on-resistance of the discharge FET
(see Figure 2). The fall time sets the delay (dead time)
between the turn-off of one output driver and the turn-on of the
other driver. A toggle flip-flop insures that drive signals to
OUTA and OUTB are alternated and therefore insures a
maximum duty cycle of less than 50% for each output driver.
Graphs of component values vs. oscillator frequency and
dead time are shown in the typical characteristic section of
this specification.
MIC3808/3809
8
April 2005
相关PDF资料 |
PDF描述 |
|---|---|
| MIC3809YM | IC REG CTRLR ISO PWM CM 8-SOIC |
| MIC38C45YM | IC REG CTRLR BST FLYBK ISO 8SOIC |
| MIC2174-1YMM | IC REG CTRLR BUCK PWM 10-MSOP |
| MIC2174C-1YMM | IC REG CTRLR BUCK PWM 10-MSOP |
| MIC2166YMME | IC REG CTRLR PWM HYBRID 10-MSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MIC3808YM TR | 功能描述:DC/DC 开关控制器 Push-Pull DC/DC Controller (Lead Free) RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MIC3808YMM | 功能描述:DC/DC 开关控制器 Push-Pull DC/DC Controller (Lead Free) RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MIC3808YMM TR | 功能描述:DC/DC 开关控制器 Push-Pull DC/DC Controller (Lead Free) RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MIC3809 | 制造商:MIC 制造商全称:MIC GROUP RECTIFIERS 功能描述:Push-Pull PWM Controller |
| MIC3809BM | 功能描述:IC REG CTRLR ISO PWM CM 8-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:40-VFQFN 裸露焊盘 包装:带卷 (TR) |
发布紧急采购，3分钟左右您将得到回复。