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参数资料
| 型号： | SP7655EB |
| 厂商： | Exar Corporation |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | EVAL BOARD FOR SP7655 |
| 标准包装： | 1 |
| 系列： | * |
PIN DESCRIPTION
Pin #
1-3
4,8,19-21
5
6
7
9
10-13
14-16,23-26
17
18
22
Pin Name
P GND
GND
V FB
COMP
UVIN
SS
V IN
LX
NC
BST
Vcc
Description
Ground connection for the synchronous rectifier
Ground Pin. The control circuitry of the IC and lower power driver are
referenced to this pin. Return separately from other ground traces to the (-)
terminal of C OUT .
Feedback Voltage and Short Circuit Detection pin. It is the inverting input of
the Error Amplifier and serves as the output voltage feedback point for the
Buck Converter. The output voltage is sensed and can be adjusted through
an external resistor divider. Whenever V FB drops 0.25V below the positive
reference, a short circuit fault is detected and the IC enters hiccup mode.
Output of the Error Amplifier. It is internally connected to the inverting input of
the PWM comparator. An optimal filter combination is chosen and connected
to this pin and either ground or V FB to stabilize the voltage mode loop.
UVLO input for V IN voltage. Connect a resistor divider between V IN and UV IN
to set minimum operating voltage.
Soft Start. Connect an external capacitor between SS and GND to set the
soft start rate based on the 10μA source current. The SS pin is held low via a
1mA (min) current during all fault conditions.
Input connection to the high side N-channel MOSFET. Place a decoupling
capacitor between this pin and PGND.
Connect an inductor between this pin and V OUT
No Connect
High side driver supply pin. Connect BST to the external boost diode and
capacitor as shown in the Typical Application Circuit on page 1. High side
driver is connected between BST pin and SWN pin.
Input for external 5V bias supply
General Overview
The SP7655 is a fixed frequency, voltage mode,
synchronous PWM regulator optimized for high
efficiency. The part has been designed to be
especially attractive for high voltage applica-
tions utilizing 5V to power the controller and
2.5V to 28V for step down conversion.
The heart of the SP7655 is a wide bandwidth
transconductance amplifier designed to accom-
modate Type II and Type III compensation
schemes. A precision 0.8V reference, present on
the positive terminal of the error amplifier,
permits the programming of the output voltage
down to 0.8V via the V FB pin. The output of the
error amplifier, COMP, compared to a 1.1V
peak-to-peak ramp is responsible for trailing
edge PWM control. This voltage ramp, and
PWM control logic are governed by the internal
oscillator that accurately sets the PWM fre-
quency to 300kHz.
THEORY OF OPERATION
The SP7655 contains two unique control fea-
tures that are very powerful in distributed appli-
cations. First, asynchronous driver control is
enabled during startup, to prohibit the low side
switch from pulling down the output until the
high side switch has attempted to turn on. Sec-
ond, a 100% duty cycle timeout ensures that the
low side switch is periodically enhanced during
extended periods at 100% duty cycle. This guar-
antees the synchronized refreshing of the BST
capacitor during very large duty cycle ratios.
The SP7655 also contains a number of valuable
protection features. Programmable V IN UVLO
allows the user to set the exact value at which the
conversion voltage can safely begin down con-
version, and an internal V CC UVLO which en-
sures that the controller itself has enough volt-
age to operate properly. Other protection fea-
Rev E: 3/2 /07
SP7655 Wide Input Voltage Range 8A, 300kHz, Buck Regulator
? 2007 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7655ER | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7655ER/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 8Amp 300kHz, Buck Regulator |
| SP7655ERL | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 8Amp 300kHz, Buck Regulator |
| SP7655ER-L | 功能描述:线性稳压器 - 标准 Buck Regulator RoHS:否 制造商:STMicroelectronics 输出类型: 极性: 输出电压:1.8 V 输出电流:150 mA 负载调节: 最大输入电压:5.5 V 线路调整率: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SOT-323-5L |
| SP7655ERL/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range, 8Amp 300kHz, Buck Regulator |
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