- 您现在的位置：买卖IC网 > PDF目录1841 > MAX1951AESA+T (Maxim Integrated Products)IC REG BUCK SYNC ADJ 2A 8SOIC PDF资料下载
参数资料
| 型号： | MAX1951AESA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/12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, 2A, 2.6V to 5.5V Input, PWM DC-DC
Step-Down Regulator with Enable
Pin Description
internal clock, the internal high-side MOSFET turns on
until the PWM comparator trips. During this on-time, cur-
PIN NAME
FUNCTION
rent ramps up through the inductor, sourcing current to
1
2
3
4
5
V CC
EN
GND
FB
COMP
Supply Voltage. Bypass with a 0.1μF capacitor
to ground and a 10 ? resistor to IN.
Enable Input. Connect to V CC for normal
operation. Connect to GND to disable the
MAX1951A.
Signal Ground
Feedback Input. 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 .
Regulator Compensation. Connect series RC
network to GND.
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
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
6
Power Ground. Internally connected to GND.
PGND Keep power ground and signal ground planes
separate.
output capacitor stores charge when the inductor current
exceeds the load current, and discharges when the
inductor current is lower, smoothing the voltage across
the load. Under overload conditions, when the inductor
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 with a 10μF (min)
ceramic capacitor to GND and a 10 ? resistor
to V CC .
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
high-side MOSFET on-resistance and the inductor cur-
Detailed Description
The MAX1951A high-efficiency switching regulator is a
small, simple, current-mode DC-DC step-down convert-
er capable of delivering up to 2A of output current. The
device operates in pulse-width modulation (PWM) at a
fixed frequency of 1MHz from a 2.6V to 5.5V input volt-
age and provides an output voltage from 0.8V to V IN ,
making the MAX1951A ideal for on-board postregula-
tion applications. The high switching frequency allows
for the use of smaller external components, and an
internal synchronous rectifier improves efficiency and
eliminates the typical Schottky free-wheeling diode.
Using the on-resistance of the internal high-side MOS-
FET to sense switching currents eliminates current-
sense resistors, further improving efficiency and cost.
The MAX1951A total output error over load, line, and
temperature (-40°C to +85°C) is less than 1.5%.
Controller Block Function
The MAX1951A step-down converter uses a PWM cur-
rent-mode control scheme. An open-loop comparator
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
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 exceed-
ed. A synchronous rectifier current limit of -0.6A (typ) pro-
tects the device from current flowing into LX. If the
negative current limit is exceeded, the synchronous recti-
fier turns off, forcing the inductor current to flow through
the high-side MOSFET body diode, back to the input, until
the beginning of the next cycle or until the inductor cur-
rent drops to zero. The MAX1951A utilizes a pulse-skip
mode to prevent overheating during short-circuit output
conditions. The device enters pulse-skip mode when the
FB voltage drops below 300mV, limiting the current to 3A
(typ) and reducing power dissipation. Normal operation
resumes upon removal of the short-circuit condition.
6
_______________________________________________________________________________________
相关PDF资料 |
PDF描述 |
|---|---|
| MAX1951ESA+W | IC REG BUCK SYNC ADJ 2A 8SOIC |
| MAX1954AEUB+T | IC REG CTRLR BUCK PWM CM 10-UMAX |
| MAX1954EUB+ | IC REG CTRLR BUCK PWM CM 10-UMAX |
| MAX1956ETI+T | IC REG CTRLR BUCK PWM VM 28-TQFN |
| MAX1961EEP+ | IC REG CTRLR BUCK PWM VM 20-QSOP |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1951ESA | 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 |
| MAX1951ESA+ | 功能描述:直流/直流开关调节器 1MHz 2A 2.6-5.5V PWM DC/DC Step-Down 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 |
| MAX1951ESA+T | 功能描述:直流/直流开关调节器 1MHz 2A 2.6-5.5V PWM DC/DC Step-Down 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 |
| MAX1951ESA+TW | 功能描述:直流/直流开关调节器 1MHz 2A 2.6-5.5V PWM DC/DC Step-Down 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 |
| MAX1951ESA+W | 功能描述:直流/直流开关调节器 1MHz 2A 2.6-5.5V PWM DC/DC Step-Down 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 |
发布紧急采购，3分钟左右您将得到回复。