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| 型号： | MAX1951ESA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 2A 8SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.8 V ~ 5.5 V |
| 输入电压： | 2.6 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1MHz |
| 电流 - 输出： | 2A |
| 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： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 8-SOIC |
1MHz, All-Ceramic, 2.6V to 5.5V Input,
2A PWM Step-Down DC-to-DC Regulators
Pin Description
Controller Block Function
The MAX1951/MAX1952 step-down converters use a
PIN NAME
FUNCTION
PWM current-mode control scheme. An open-loop com-
1
2
3
4
V CC
REF
GND
FB
Supply Voltage. Bypass V CC with 0.1μF
capacitor to ground and 10 Ω resistor to IN.
Reference Bypass. Bypass REF with 0.1μF
capacitor to ground.
Ground
Feedback Input. Connect FB to the output to
regulate using the internal feedback resistor
string (MAX1952). Connect an external resistor-
divider from the output to FB and GND to set
the output to a voltage between 0.8V and V IN
(MAX1951).
Regulator Compensation. Connect series RC
network from COMP to GND. Pull COMP below
parator compares the integrated voltage-feedback signal
against the sum of the amplified current-sense signal and
the slope compensation ramp. At each rising edge of the
internal clock, the internal high-side MOSFET turns on
until the PWM comparator trips. During this on-time, cur-
rent ramps up through the inductor, sourcing current to
the output and storing energy in the inductor. The current-
mode feedback system regulates the peak inductor cur-
rent as a function of the output voltage error signal. Since
the average inductor current is nearly the same as the
peak inductor current (<30% ripple current), the circuit
acts as a switch-mode transconductance amplifier. To
preserve inner-loop stability and eliminate inductor stair-
casing, a slope-compensation ramp is summed into the
main PWM comparator. During the second half of the
5
6
COMP 0.17V to shut down the regulator. COMP =
GND when V IN is less than 2.25V (see the
Compensation and Shutdown Mode section)
Power Ground. Internally connected to GND.
PGND Keep power ground and signal ground planes
separate.
cycle, the internal high-side p-channel MOSFET turns off,
and the internal low-side n-channel MOSFET turns on.
The inductor releases the stored energy as its current
ramps down while still providing current to the output. The
output capacitor stores charge when the inductor current
exceeds the load current, and discharges when the
inductor current is lower, smoothing the voltage across
7
8
LX
IN
Inductor Connection. Connect an inductor
between LX and the regulator output.
Power-Supply Voltage. Input voltage range
from 2.6V to 5.5V. Bypass IN with a 10μF (min)
ceramic capacitor to GND and a 10 Ω resistor
to V CC .
the load. Under overload conditions, when the inductor
current exceeds the current limit (see the Current Limit
section), the high-side MOSFET does not turn on at the
rising edge of the clock and the low-side MOSFET
remains on to let the inductor current ramp down.
Current Sense
An internal current-sense amplifier produces a current
signal proportional to the voltage generated by the
Detailed Description
The MAX1951/MAX1952 high-efficiency switching regula-
tors are small, simple, DC-to-DC step-down converters
capable of delivering up to 2A of output current. The
devices operate in pulse-width modulation (PWM) at a
fixed frequency of 1MHz from a 2.6V to 5.5V input voltage
and provide an output voltage from 0.8V to V IN , making
the MAX1951/MAX1952 ideal for on-board postregula-
tion applications. The high switching frequency allows
for the use of smaller external components, and internal
synchronous rectifiers improve efficiency and eliminate
the typical Schottky free-wheeling diode. Using the on-
resistance of the internal high-side MOSFET to sense
switching currents eliminates current-sense resistors,
further improving efficiency and cost. The MAX1951
total output error over load, line, and temperature (0°C
to +85°C) is less than 1%.
high-side MOSFET on-resistance and the inductor cur-
rent (R DS(ON) x I LX ). The amplified current-sense signal
and the internal slope compensation signal are
summed together into the comparator’s inverting input.
The PWM comparator turns off the internal high-side
MOSFET when this sum exceeds the output from the
voltage-error amplifier.
Current Limit
The internal high-side MOSFET has a current limit of 3.1A
(typ). If the current flowing out of LX exceeds this limit,
the high-side MOSFET turns off and the synchronous
rectifier turns on. This lowers the duty cycle and causes
the output voltage to droop until the current limit is no
longer exceeded. A synchronous rectifier current limit of
-0.6A (typ) protects the device from current flowing into
LX. If the negative current limit is exceeded, the synchro-
nous rectifier turns off, forcing the inductor current to flow
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1951ESA-TG05 | 功能描述:直流/直流开关调节器 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX1951EVKIT | 功能描述:直流/直流开关调节器 Evaluation Kit for the MAX1951 MAX1952 RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| MAX19526EVKIT+ | 制造商:Maxim Integrated Products 功能描述:ANALOG TO DIGITAL CONVERTER - Boxed Product (Development Kits) |
| MAX19526EXE+ | 功能描述:模数转换器 - ADC Integrated Circuits (ICs) Analog to Digital Converters - IC ADC 12BIT 8CH 40MSPS 144CTBGA RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
| MAX19526EXE+T | 功能描述:模数转换器 - ADC Integrated Circuits (ICs) Analog to Digital Converters - IC ADC 12BIT 8CH 40MSPS 144CTBGA RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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