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参数资料
| 型号： | NCP1450ASN19T1 |
| 厂商： | ON Semiconductor |
| 文件页数： | 19/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST PWM VM 5TSOP |
| 产品变化通告： | LTB Notification 03/Jan/2008 |
| 标准包装： | 1 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 216kHz |
| 占空比： | 90% |
| 电源电压： | 0.6 V ~ 5.5 V |
| 降压： | 无 |
| 升压： | 是 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 6-TSOP（0.059"，1.50mm 宽）5 引线 |
| 包装： | 剪切带 (CT) |
| 其它名称： | NCP1450ASN19TOSCT |
NCP1450A
Diode
The diode is the largest source of loss in DC?DC
converters. The most importance parameters which affect
their efficiency are the forward voltage drop, V D , and the
reverse recovery time, trr. The forward voltage drop creates
a loss just by having a voltage across the device while a
current flowing through it. The reverse recovery time
generates a loss when the diode is reverse biased, and the
current appears to actually flow backwards through the
diode due to the minority carriers being swept from the P?N
junction. A Schottky diode with the following
characteristics is recommended:
Small forward voltage, V F t 0.3 V
Small reverse leakage current
Fast reverse recovery time/switching speed
Rated current larger than peak inductor current,
I rated u I PK
Reverse voltage larger than output voltage,
more efficient switch than a BJT transistor. However, the
MOSFET requires a higher voltage to turn on as compared
with BJT transistors. An enhancement N?channel MOSFET
can be selected by the following guidelines:
1. Low ON?resistance, R DS(on) , typically < 0.1 W .
2. Low gate threshold voltage, V GS(th) , must be <
V OUT , typically < 1.5 V, it is especially important
for the low V OUT device, like V OUT = 1.9 V.
3. Rated continuous drain current, I D , should be
larger than the peak inductor current, i.e. I D > I PK .
4. Gate capacitance should be 1200 pF or less.
For bipolar NPN transistor, medium power transistor with
continuous collector current typically 1 A to 5 A and V CE(sat)
< 0.2 V should be employed. The driving capability is
determined by the DC current gain, H FE , of the transistor and
the base resistor, Rb; and the controller ’s EXT pin must be
able to supply the necessary driving current.
Rb can be calculated by the following equation:
Rb + OUT *
V reverse u V OUT
Input Capacitor
V
Ib
0.7
*
0.4
| IEXTH|
Ib + PK
Cb v
The input capacitor can stabilize the input voltage and
minimize peak current ripple from the source. The value of
the capacitor depends on the impedance of the input source
used. Small Equivalent Series Resistance (ESR) Tantalum
or ceramic capacitor with a value of 10 m F should be
suitable.
Output Capacitor
The output capacitor is used for sustaining the output
voltage when the external MOSFET or bipolar transistor is
switched on and smoothing the ripple voltage. Low ESR
capacitor should be used to reduce output ripple voltage. In
general, a 100 m F to 220 m F low ESR (0.10 W to 0.30 W )
Tantalum capacitor should be appropriate.
External Switch Transistor
An enhancement N?channel MOSFET or a bipolar NPN
transistor can be used as the external switch transistor.
For enhancement N?channel MOSFET, since
enhancement MOSFET is a voltage driven device, it is a
External Component Reference Data
I
HFE
Since the pulse current flows through the transistor, the
exact Rb value should be finely tuned by the experiment.
Generally, a small Rb value can increase the output current
capability, but the efficiency will decrease due to more
energy is used to drive the transistor.
Moreover, a speed?up capacitor, Cb, should be connected
in parallel with Rb to reduce switching loss and improve
efficiency. Cb can be calculated by the equation below:
1
2 p Rb fOSC 0.7
It is due to the variation in the characteristics of the
transistor used. The calculated value should be used as the
initial test value and the optimized value should be obtained
by the experiment.
Inductor
Inductor
External
Output
Device
NCP1450ASN19T1
NCP1450ASN30T1
NCP1450ASN50T1
NCP1450ASN19T1
NCP1450ASN30T1
NCP1450ASN50T1
V OUT
1.9 V
3.0 V
5.0 V
1.9 V
3.0 V
5.0 V
Model
CD54
CD54
CD54
CD54
CD54
CD54
Value
12 m H
10 m H
10 m H
12 m H
10 m H
10 m H
Transistor
NTGS3446T1
NTGS3446T1
NTGS3446T1
MMJT9410
MMJT9410
MMJT9410
Diode
MBRM110L
MBRM110L
MBRM110L
MBRM110L
MBRM110L
MBRM110L
Capacitor
220 m F
220 m F
220 m F
220 m F
220 m F
220 m F
http://onsemi.com
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| NCP1450ASN19T1G | 功能描述:直流/直流开关转换器 1.9V 1A Boost DC-DC PWM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP1450ASN27T1 | 功能描述:直流/直流开关转换器 2.7V 1A Boost DC-DC RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP1450ASN27T1G | 功能描述:直流/直流开关转换器 2.7V 1A Boost DC-DC PWM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP1450ASN30T1 | 功能描述:直流/直流开关转换器 3V 1A Boost DC-DC RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| NCP1450ASN30T1G | 功能描述:直流/直流开关转换器 3V 1A Boost DC-DC PWM RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
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