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参数资料
| 型号： | MAX1947ETA25+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/11页 |
| 文件大小： | 0K |
| 描述： | IC REG BST SYNC 2.5V 0.25A 8TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 类型： | 升压（升压） |
| 输出类型： | 固定 |
| 输出数： | 1 |
| 输出电压： | 2.5V |
| 输入电压： | 0.7 V ~ 3.6 V |
| 频率 - 开关： | 最高 2MHz |
| 电流 - 输出： | 250mA |
| 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-WDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 供应商设备封装： | 8-TDFN-EP（3x3） |
| 其它名称： | MAX1947ETA25+TDKR |
Low Input/Output Voltage
Step-Up DC-DC Converter with RESET
Functional Diagram
BATT
STARTUP
OSCILLATOR
75ms TIMER
0.9 x REF
RESET
OUT
SHDN
SHUTDOWN
CIRCUITRY
ERROR
AMPLIFIER
REF
t ON
MAX TIMER
CONTROL
LOGIC AND
P*
t OFF
MIN TIMER
GATE DRIVERS
ZERO-CROSSING
AMPLIFIER
LX
N
REF
1.25V REFERENCE
CURRENT-LIMIT
AMPLIFIER
PGND
(REF)
MAX1947
GND
Control Scheme
The MAX1947 is a bootstrapped design. Upon turn-on,
a startup oscillator brings the output voltage high
enough to allow the main DC-DC circuitry to run. Once
the output voltage reaches 1.62V (typ) the main DC-DC
circuitry turns on and boosts the output voltage to the
final regulation point.
The unique minimum off-time, current-limited control
scheme is the key to the MAX1947’s low operating cur-
rent and high efficiency over a wide load range. The
architecture combines the high output power and effi-
ciency of a pulse-width modulation (PWM) device with
the ultra-low quiescent current of a traditional pulse-
skipping controller. The switching frequency can be as
high as 2MHz and depends upon the load current and
input voltage. The MAX1947 is designed to operate
using low-ESR ceramic capacitors, so output voltage
ripple due to ESR is very small (approximately 10mV P-P ).
Track Mode
The MAX1947 enters track mode when BATT is greater
than the output-voltage regulation point. Track mode
can only be entered under the following conditions:
*BODY DIODE CONTROL
V BATT > V OUT , V OUT > V OUT regulation point, and the
minimum off-time expires. During track mode, the syn-
chronous rectifier is turned on 100% of the time and the
output voltage tracks the battery voltage. Track mode is
exited by V OUT falling below the V OUT regulation point.
Synchronous Rectification
The internal synchronous rectifier eliminates the need
for an external Schottky diode, reducing cost and board
space. During the cycle off-time, the p-channel MOSFET
turns on and shunts the MOSFET body diode. As a
result, the synchronous rectifier significantly improves
efficiency without the addition of an external compo-
nent. Conversion efficiency can be as high as 94%.
RESET
The MAX1947 features an active-low push-pull RESET
output for use with a microcontroller (μC). It signals the
μC when the MAX1947 output voltage is within operat-
ing limits. During startup, RESET is held low. When the
RESET threshold (90% of the output regulation voltage)
is reached, a 75ms (min) timer begins counting. RESET
is switched high once the timer expires.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1947ETA30+ | 制造商:Maxim Integrated Products 功能描述:CONV DC-DC SGL-OUT STEP UP 8TDFN EP - Rail/Tube 制造商:Maxim Integrated Products 功能描述:STEP-UP DC-DC CONVERTER WITH ACTIVE-LOW |
| MAX1947ETA30+T | 功能描述:直流/直流开关转换器 Step-Up w/RESET 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 |
| MAX1947ETA30-T | 功能描述:直流/直流开关转换器 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 |
| MAX1947ETA33 | 制造商:Maxim Integrated Products 功能描述:LOW INPUT/OUTPUT VOLTAGE STEP-UP DC-DC CONVER - Rail/Tube |
| MAX1947ETA33+ | 制造商:Maxim Integrated Products 功能描述:CONV DC-DC SGL-OUT STEP UP 8TDFN EP - Rail/Tube |
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