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参数资料
| 型号： | SP6121CN-L/TR |
| 厂商： | Exar Corporation |
| 文件页数： | 4/16页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 8NSOIC |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 560kHz |
| 占空比： | 100% |
| 电源电压： | 3 V ~ 5.5 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： | 0°C ~ 70°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
FUNCTIONAL DIAGRAM
1V
-
DRIVER ENABLE
Reference
1.25V
+
-
SHUTDOWN
V CC
FAULT
GM
300mV
+
V FB 3
0.4V/ms
SOFTSTART
+
-
ERROR
AMP
5 μ A
PWM COMP
-
+
RESET
Dominant
S
Q
PWM
Logic
Synchronous
Driver
8 PDRV
7 NDRV
COMP 4
V CC 1
R
2 GND
ISET 6
2.79V ON
2.69V OFF
-
+
PDRV
UVLO
750mV RAMP
F = 500kHz
Reset
Dominant
S
Q
FAULT
COMP
30 μ A
(3300 ppm/ ° C)
+
Over Current
(Gated S&H)
SHUTDOWN
R
X 3.3
+
ISENSE 5
-
530mV
(3300 ppm/ ° C)
-
THEORY OF OPERATION
General Overview
The SP6121 is a constant frequency, voltage
mode, synchronous PWM controller designed
for low voltage, DC/DC step down converters.
It is intended to provide complete control for a
high power, high efficiency, precisely regulated
output voltage from a highly integrated 8-pin
solution.
The internal free-running oscillator accurately
sets the PWM frequency at 500kHz without
requiring any external elements and allows the
use of physically small, low value external com-
ponents without compromising performance. A
transconductance amplifier is used for the error
amplifier, which compares an attenuated sample
of the output voltage with a precision reference
voltage. The output of the error amplifier
(COMP), is compared to a 0.75V peak-to-peak
ramp waveform to provide PWM control. The
COMP pin provides access to the output of the
error amplifier and allows the use of external
components to stabilize the voltage loop.
High efficiency is obtained through the use of
synchronous rectification. Synchronous regula-
tors replace the catch diode in the standard buck
converter with a low R DS(ON) N-channel
MOSFET switch allowing for significant effi-
ciency improvements. The SP6121 includes two
fast MOSFET drivers with internal non-overlap
circuitry and drives a complementary pair of
power transistors, P-channel on the high side,
and N-channel on the low side. The use of a P-
channel high side device minimizes complexity
and external component count by eliminating
the need for a charge pump that would otherwise
be required to fully enhance an N-channel de-
vice. It also allows inherent 100% duty cycle for
low dropout operation in the event of a low input
supply voltage condition.
The SP6121 includes an internal 0.4V/ms soft-
start circuit that provides controlled ramp up of
the output voltage, preventing overshoot and
inrush current at power up.
Current limiting is implemented by monitoring
the voltage drop across the R DS(ON) of the high
side P-channel MOSFET while it is conducting,
thereby eliminating the need for an external
sense resistor. The over-current comparator has
a built-in threshold of 160mV that can be pro-
grammed to higher values using a single exter-
nal resistor, connected to the I SET pin, whose
Date: 11/29/04
SP6121 Low Voltage, Synchronous Step Down PWM Controller
4
? Copyright 2004 Sipex Corporation
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SP6121EB | 功能描述:电压模式 PWM 控制器 Low Voltage, 8 Pin Sync Buck Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| SP6122 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122_04 | 制造商:SIPEX 制造商全称:Sipex Corporation 功能描述:Low Voltage, Micro 8, PFET, Buck Controller Ideal for 1A to 5A, Small Footprint, DC-DC Power Converters |
| SP6122ACU | 制造商:Rochester Electronics LLC 功能描述: 制造商:Exar Corporation 功能描述: |
| SP6122ACU/TR | 制造商:Exar Corporation 功能描述: |
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