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| 型号： | MAX8505EEE+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 9/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 3A 16QSOP |
| 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 ~ 4.68 V |
| 输入电压： | 2.6 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 500kHz，1MHz |
| 电流 - 输出： | 3A |
| 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： | 16-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-QSOP |
3A, 1MHz, 1% Accurate, Internal Switch
Step-Down Regulator with Power-OK
Pin Description
PIN
1, 3, 14, 16
2, 4
5
6
7
8
9
10
11
12
13, 15
NAME
LX
IN
BST
V CC
POK
CTL
COMP
FB
REF
GND
PGND
FUNCTION
Inductor Connection. Connect an inductor between these pins and the regulator output. All LX pins must
be connected together externally. Connect a 3300pF ceramic capacitor from LX to PGND.
Power-Supply Inputs. Ranges from 2.6V to 5.5V. Bypass with two ceramic 22μF capacitors to GND. All IN
pins must be connected together externally.
Bootstrapped Voltage Input. High-side driver supply pin. Bypass to LX with a 0.1μF capacitor. Charged
from IN with an external Schottky diode.
Supply Voltage and Gate-Drive Supply for Low-Side Driver. Decouple with a 10 ? resistor and bypass to
GND with 0.1μF.
Power-OK Output. Open-drain output of a window comparator that pulls POK low when the FB pin is
outside the 0.8V ± 12% range.
Output Control. When at GND, the regulator is off. When at V CC , the regulator is operating at 1MHz. For a
500kHz application, raise the pin to 2/3 V CC .
Regulator Loop Compensation. Connect a series RC network to GND. This pin is pulled to GND when the
output is shut down, or in UVLO or thermal shutdown.
Feedback Input. This pin regulates to 0.8V. Use an external resistive-divider from the output to set the
output voltage.
Place a capacitor at this pin to set the soft-start time. This pin goes to 0V when the part is shut down.
Ground
Power Ground. Connect this pin to GND at a single point.
Detailed Description
The MAX8505 is a high-efficiency synchronous buck
regulator capable of delivering up to 3A of output
current. It operates in PWM mode at a high fixed
frequency of 500kHz or 1MHz, thereby reducing
external component size. The MAX8505 operates from
a 2.6V to 5.5V input voltage and can produce an output
voltage from 0.8V to 0.85 V IN .
Controller Block Function
The MAX8505 step-down converter uses a PWM
current-mode control scheme. An open-loop comparator
compares the voltage-feedback error 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, current 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 current as a
function of the output-voltage error signal. Since the aver-
age inductor current is nearly the same as the peak
inductor current, the circuit acts as a switch-mode
transconductance amplifier. To preserve inner-loop
stability and eliminate inductor staircasing, a slope-
compensation ramp is summed into the main PWM com-
parator. During the second half of the cycle, the internal
high-side N-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
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 high-
side MOSFET on-resistance and the inductor current
(R DS(ON) 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 feedback voltage from the
voltage-error amplifier.
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相关代理商/技术参数 |
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|---|---|
| MAX8505EVKIT | 制造商:Maxim Integrated Products 功能描述:3A, 1MHZ, 1% ACCURATE, INTERNAL SWITCH STEP-D - Bulk |
| MAX8506ETE | 功能描述:直流/直流开关转换器 PWM Step-Down DC/DC Converter 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 |
| MAX8506ETE+ | 功能描述:直流/直流开关转换器 DC/DC Converter DC/DC Converter 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 |
| MAX8506ETE+T | 功能描述:直流/直流开关转换器 DC/DC Converter DC/DC Converter 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 |
| MAX8506ETE-T | 功能描述:直流/直流开关转换器 DC/DC Converter DC/DC Converter 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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