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参数资料
| 型号： | SP7661ER-L |
| 厂商： | Exar Corporation |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A 26DFN |
| 产品变化通告： | SP76(55,61)ER-L/(TR) Obsolescence 29/Jul/2011 |
| 标准包装： | 500 |
| 系列： | Power Blox™ |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 20.2 V |
| 输入电压： | 4.75 V ~ 22 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 3A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 26-VFDFN 裸露焊盘 |
| 包装： | 散装 |
| 供应商设备封装： | 26-DFN（7x4） |
APPLICATIONS INFORMATION
Error Amplifier and Voltage Loop
The heart of the SP7661 voltage error loop
is a high performance, wide bandwidth
transconductance amplifier. Because of
the amplifier ’s current limited (+/-150μA)
transconductance, there are many ways to
compensate the voltage loop or to control the
COMP pin externally. If a simple, single-pole,
single-zero response is desired, then com -
pensation 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.
The common mode output of the error am -
plifier 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 a
nonsynchronous startup mode. Basically, the
synchronous rectifier 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 controller from “dragging
down” the output voltage during startup or
in fault modes.
VBST
GH
Voltage
VSWN
V(VCC)
The second feature is a 100% duty cycle
timeout that ensures synchronized refresh -
ing of the BST capacitor 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 BST capacitor.
The boost capacitor is used to generate a
high voltage drive supply for the high side
switch, which is Vcc above V IN .
Power MOSFETs
The SP7661 contains a pair of integrated low
resistance N-channel switches designed to
drive up to 3A of output current. 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 current could be
limited by thermal limitations of a particular
application by taking advantage of the inte -
grated-over-temperature protective scheme
employed in the SP7661. The SP7661 incor -
porates a built-in overtemperature protection
to prevent internal overheating.
Setting Output Voltages
The SP7661 can be set to different output
voltages. 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.
GL
Voltage
0V
V(VIN)
SWN
Voltage
-0V
-V(Diode) V
V(VIN)+V(VCC)
BST
Voltage
V(VCC)
TIME
V OUT = 0.80V [ R1 / R2 + 1 ] =>
R2 = R1 / [ ( V OUT / 0.80V ) – 1 ]
Where R1 = 10KΩ and for V OUT = 0.80V
setting, simply remove R2 from the board.
Furthermore, one could select the value of
the R1 and R2 combination to meet the exact
output voltage setting by restricting the R1
resistance range such that 10KΩ < R1 <
100KΩ for overall system loop stability.
Mar -07 Rev N
SP766 Wide Input Voltage Range 3A, 600kHz Buck Regulator
9
? 2007 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP7661ERL/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 3A, 600kHz, Buck Regulator |
| SP7661ER-L/TR | 功能描述:开关变换器、稳压器与控制器 WIDE INPUT VOLTAGE Range A600KHz RoHS:否 制造商:Texas Instruments 输出电压:1.2 V to 10 V 输出电流:300 mA 输出功率: 输入电压:3 V to 17 V 开关频率:1 MHz 工作温度范围: 安装风格:SMD/SMT 封装 / 箱体:WSON-8 封装:Reel |
| SP7662 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Evaluation Board Manual |
| SP7662_07 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Wide Input Voltage Range 12A, 300kHz, Buck Regulator |
| SP7662_1 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Evaluation Board Manual |
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