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参数资料
| 型号： | SP7653EB |
| 厂商： | Exar Corporation |
| 文件页数： | 6/15页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP7653 |
| 标准包装： | 1 |
| 系列： | * |
THEORY OF OPERATION
pin externally. If a simple, single-pole single-
zero response is desired, then compensation can
be as simple as an RC circuit to Ground. If a
more complex compensation is required, then
the amplifier has enough bandwidth (45 ° at 4
MHz) and enough gain (60dB) to run Type III
compensation schemes with adequate gain and
phase margins at crossover frequencies greater
than 50kHz.
VBST
GH
Voltage
VSWN
V(VCC)
GL
Voltage
0V
The common mode output of the error amplifier
is 0.9V to 2.2V. Therefore, the PWM voltage
ramp has been set between 1.1V and 2.2V to
ensure proper 0% to 100% duty cycle capability.
The voltage loop also includes two other very
important features. One is an asynchronous
startup mode. Basically, the synchronous recti-
fier cannot turn on unless the high side switch
has attempted to turn on or the SS pin has
exceeded 1.7V. This feature prevents the con-
troller from “dragging down” the output voltage
during startup or in fault modes. The second
V(VIN)
SWN
Voltage
-0V
-V(Diode) V
V(VIN)+V(VCC)
BST
Voltage
V(VCC)
TIME
R2 =
feature is a 100% duty cycle timeout that en-
sures synchronized refreshing of the Boost ca-
pacitor at very high duty ratios. In the event that
the high side NFET is on for 20 continuous
clock cycles, a reset is given to the PWM flip-
flop half way through the 21 st cycle. This forces
GL to rise for the cycle, in turn refreshing the
Boost capacitor. The boost capacitor is used to
generate a high voltage drive supply for the high
side switch, which is 5V above V IN .
Power MOSFETs
The SP7653 contains a pair of integrated low
resistance N-channel switches designed for up
to 3Amps. Care should be taken to de-rate the
output current based on the thermal conditions
in the system such as ambient temperature,
airflow and heat sinking. Maximum output cur-
rent could be limited by thermal limitations of a
particular application by taking advantage of
the integrated-over-temperature protective
scheme employed in the SP7653. The SP7653
incorporates a built-in overtemperature protec-
tion to prevent internal overheating.
Setting Output Voltages
The SP7653 can be set to different output volt-
ages. The relationship in the following formula
is based on a voltage divider from the output to
the feedback pin V FB , which is set to an internal
reference voltage of 0.80V. Standard 1% metal
film resistors of surface mount size 0603 are
recommended.
V OUT = 0.80V ( R1 / R2 + 1 ) =>
R1 .
{ ( V OUT / 0.80V ) – 1 }
Where R1 = 68.1K and for V OUT = 0.80V
setting, simply remove R2 from the board. Fur-
thermore, one could select the value of the R1
and R2 combination to meet the exact output
voltage setting by restricting the resistance range
of R1 such that 50K < R1 < 100K for overall
system loop stability.
Date: 2/17/06
SP7653 Wide Input Voltage Range, 1.3MHz, Buck Regulator
? Copyright 2006 Sipex Corporation
Date: /20/06
SP7653 Wide Input Voltage Range, .3MHz, Buck Regulator
6
? Copyright 2006 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7653ER | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 1.3MHz,Buck Regulator |
| SP7653ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 1.3MHz, Buck Regulator |
| SP7653ERL | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 1.3MHz, Buck Regulator |
| SP7653ER-L | 功能描述:DC/DC 开关控制器 Regulator 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 |
| SP7653ERL/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 1.3MHz, Buck Regulator |
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