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参数资料
| 型号： | NCP1530DM25R2 |
| 厂商： | ON Semiconductor |
| 文件页数： | 11/16页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK 2.5V 0.6A MICRO8 |
| 产品变化通告： | LTB Notification 03/Jan/2008 |
| 标准包装： | 4,000 |
| 类型： | 降压（降压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 2.5V |
| 输入电压： | 3.5 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 600kHz |
| 电流 - 输出： | 600mA |
| 同步整流器： | 无 |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-TSSOP，8-MSOP（0.118"，3.00mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | Micro8? |
NCP1530
DETAILED OPERATING DESCRIPTION
Introduction
The NCP1530 series are step?down converters with a
smart control scheme that operates with 600 kHz fixed
Pulse Width Modulation (PWM) at moderate to heavy load
currents, so that high efficiency, noise free output voltage
can be generated. In order to improve the system efficiency
at light loads, this device can be configured to work in
auto?mode. In auto?mode operation, the control unit will
detect the loading condition and switch to power saving
Pulse Frequency Modulation (PFM) control scheme at
light load. With these enhanced features, the converter can
achieve high operating efficiency for all loading
conditions. Additionally, the switching frequency can also
be synchronized to external clock signal in between
600 kHz to 1.2 MHz range. The converter uses peak
current mode PWM control as a core, with the high
switching frequency incorporated. Good line and load
regulation can be achieved easily with small value ceramic
input and output capacitors. Internal integrated
controlling the ramp up of the internal voltage reference.
The soft?start time can be user adjusted by an external
capacitor, C SS , connecting to the SS pin (pin 3). During
converter powerup, a 50 nA current flowing out from the
SS pin will charge?up the timing capacitor. The voltage
across the SS pin controls the ramp up of the internal
reference voltage by slowly releasing it until the nominal
value is reached. For an external timing capacitor of value
C SS = 100 pF, the soft?start time is about 5.0 ms including
the small logic delay time, Figure 33 and 34. In the case
where the SS pin is left floating, a small built?in capacitor
together with other parasitic capacitance will provide a
minimum intrinsic soft?start time of 500 m s. As the
soft?start function is implemented by simple circuitry, the
final timing depends on non?linear functions, where
accurate deterination of the soft?start timing is impossible.
However, for simplicity, the empirical formula below can
be used to estimate the soft?start time with respect to the
value of the external capacitor.
compensation voltage ramp ensures stable operation at all
operating modes. NCP1530 series are designed to support
tSS in m s [ 50
CSS in pF ) 500 m s
up to 600 mA output current with cycle?by?cycle current
limit protection.
The Internal Oscillator
The oscillator that governs the switching of the PWM
control cycle is self contained and no external timing
component is required to setup the switching frequency.
For PWM mode and auto?mode operation, all timing
signals required for proper operation are derived from the
internal oscillator. The internal fix frequency oscillator is
trimmed to run at 600 kHz " 20% over full temperature
range. In case the device is forced to operate at
Synchronization mode by applying an external clock signal
to SYN pin (pin 2), the external clock signal will supersede
the internal oscillator and take charge of the switching
operation.
Voltage Reference and Soft?Start
An internal high accuracy voltage reference is included
in NCP1530. This reference voltage governs all internal
reference levels in various functional blocks required for
proper operation. This reference voltage is precisely
trimmed to 1.2 V " 1.5% over full temperature range. The
reference voltage can be accessed externally at V REF pin
(pin 7), with an external capacitor, C REF of 1.0 m F, privding
up to 5.0 mA of loading. Additionally, NCP1530 has a
Soft?Start circuit built around the voltage reference block
that provide limits to the inrush current during start?up by
Current Mode Pulse?Width Modulation (PWM)
Control Scheme
With the SYN pin (pin 2) connected to V IN , the converter
will set to operate at constant switching frequency PWM
mode. NCP1530 uses peak current mode control scheme to
achieve good line and load regulation. The high switching
frequency, 600 kHz, and a carefully compensated internal
control loop, allows the use of low profile small value
ceramic type input and output capacitor for stable
operation. In current mode operation, the required ramp
function is generated by sensing the inductor current
(ISEN) and comparing with the voltage loop error
amplifier (OTA) output. The OTA output is derived from
feedback from the output voltage pin (V OUT ? Pin 6) and
the internal reference voltage (V REF ? Pin 7). See Figure 2.
On a cycle?by?cycle basis, the duty cycle is controlled to
keep the output voltage within regulation. The current
mode approach has outstanding line regulation
performance and good overall system stability.
Additionally, by monitoring the inductor current, a
cycle?by?cycle current limit protection is implemented.
Constant Frequency PWM scheme reduces output ripple
and noise, which is one of the important characteristics for
noise sensitive communication applications. The high
switching frequency allows the use of small size surface
mount components that saves significant PC board area and
improves layout compactness and EMI performance.
http://onsemi.com
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| NCP1530DM25R2G | 功能描述:直流/直流开关转换器 600mA PWM/PFM Buck 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 |
| NCP1530DM27R2 | 功能描述:直流/直流开关转换器 600mA PWM/PFM Buck 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 |
| NCP1530DM27R2G | 功能描述:直流/直流开关转换器 600mA PWM/PFM Buck 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 |
| NCP1530DM30R2 | 功能描述:直流/直流开关转换器 600mA PWM/PFM Buck 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 |
| NCP1530DM30R2G | 功能描述:直流/直流开关转换器 600mA PWM/PFM Buck 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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