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参数资料
| 型号： | SP6654ER-L/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 9/17页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 0.8A 10DFN |
| 标准包装： | 3,000 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1 V ~ 5.5 V |
| 输入电压： | 2.7 V ~ 5.5 V |
| 电流 - 输出： | 800mA |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 10-VFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 10-DFN（3x3） |
OPERATION: Continued
regulation. Once RESET occurs T ON minimum
is reset, and the T OFF one-shot is triggered to
blank the loop comparator from starting a new
charge cycle for a minimum period. This blank-
ing period occurs during the noisy LX transition
to discharge, where spurious comparator states
may occur. For T OFF > T BLANK the loop is in a
L = Inductor value
I OUT = Load current
R CH = PMOS on resistance, 0.3 ? typ.
If the I OUT * R CH term is negligible compared
with (V IN - V OUT ), the above equation simplifies
to:
discharge or wait state until the loop comparator
starts the next charge cycle by DRVON going
high.
I LR ≈
K ON
L
(V IN - V OUT ) * (V OUT + I OUT * R DC )
If an over current occurs during charge the loop
is interrupted and DRVON is RESET. The off-
time one-shot pulse width is widened to T OFF =
K OFF / V OUT , which holds the loop in discharge
for that time. At the end of the off-time the loop
is released and controlled by VOLOW. In this
manner maximum inductor current is controlled
on a cycle-by-cycle basis. An assertion of UVLO
(undervoltage lockout) or TSD (thermal shut-
down) holds the loop in no-charge until the fault
has ended.
On-Time Control - Discharge Phase
The discharge phase follows with the high side
PMOS switch opening and the low side NMOS
switch closing to provide a discharge path for
the inductor current. The decreasing inductor
current and the load current cause the output
voltage to drop. Under normal load conditions
when the inductor current is below the pro-
grammed limit, the off-time will continue until
the output voltage falls below the regulation
threshold, which initiates a new charge cycle via
the loop comparator.
The inductor current “floats” in continuous con-
duction mode. During this mode the inductor
For most applications, the inductor current ripple
controlled by the SP6654 is constant regardless
of input and output voltage. Because the output
voltage ripple is equal to:
V OUT (ripple) = I LR * R ESR
where:
R ESR = ESR of the output capacitor
the output ripple of the SP6654 regulator is
independent of the input and output voltages.
For battery powered applications, where the
battery voltage changes significantly, the SP6654
provides constant output voltage ripple through-
out the battery lifetime. This greatly simplifies
the LC filter design.
The maximum loop frequency in CCM is de-
fined by the equation:
F LP ≈
K ON * [V IN + I OUT * (R DC - R CH )]
where:
F LP = CCM loop frequency
R DC = NMOS on resistance, 0.3 ? typ.
Ignoring conduction losses simplifies the loop
frequency to:
peak current is below the programmed limit and
the valley current is above zero. This is to satisfy
load currents that are greater than half the mini-
F LP ≈
1
K ON
*
V OUT
V IN
* (V IN - V OUT )
mum current ripple. The current ripple, I LR , is
defined by the equation:
AND’ing the loop comparator and the on-timer
reduces the switching frequency for load cur-
I LR ≈
K ON
L
*
V IN - V OUT - I OUT * R CH
V IN - V OUT
rents below half the inductor ripple current. This
increases light load efficiency. The minimum
on-time insures that the inductor current ripple
where:
is a minimum of K ON /L, more than the load
Date: 2/1/05
SP6654 High Efficiency 800mA Synchronous Buck Regulator
9
? Copyright 2005 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP6654EU | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP6654EU/TR | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Efficiency 800mA Synchronous Buck Regulator |
| SP6654EU-L | 功能描述:DC/DC 开关控制器 High Eff 800mA Synchronous 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 |
| SP6654EU-L/TR | 功能描述:DC/DC 开关控制器 High Eff 800mA Synchronous 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 |
| SP6655 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:High Efficiency 400mA Synchronous Buck Regulator Ideal for portable designs powered with Li Ion battery |
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