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| 型号： | MAX1649ESA+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM 8-SOIC |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 控制器 |
| 输出数： | 1 |
| 频率 - 最大： | 300kHz |
| 占空比： | 96.5% |
| 电源电压： | 3 V ~ 16 V |
| 降压： | 是 |
| 升压： | 无 |
| 回扫： | 无 |
| 反相： | 无 |
| 倍增器： | 无 |
| 除法器： | 无 |
| Cuk： | 无 |
| 隔离： | 无 |
| 工作温度： | -40°C ~ 85°C |
| 封装/外壳： | 8-SOIC（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
5V/3.3V or Adjustable, High-Efficiency,
Low-Dropout, Step-Down DC-DC Controllers
______________________________________________________________Pin Description
PIN NAME
FUNCTION
Sense Input for fixed 5V or 3.3V output operation. OUT is internally connected to the on-chip voltage divider.
1
2
3
4
5
6
7
8
OUT
FB
SHDN
REF
V+
CS
EXT
GND
V IN
Although it is connected to the output of the circuit, OUT does not supply current. Leave OUT unconnected for
adjustable-output operation.
Feedback Input. Connect to GND for fixed-output operation. Connect a resistor divider between OUT, FB, and
GND for adjustable-output operation. See Setting the Output Voltage section.
Active-High Shutdown Input. Part is placed in shutdown when SHDN is driven high. In shutdown mode, the refer-
ence, output, and external MOSFET are turned off. Connect to GND for normal operation.
1.5V Reference Output that can source 100μA. Bypass with 0.1μF.
Positive Power-Supply Input
Current-Sense Input. Connect current-sense resistor between V+ and CS. When the voltage across the resistor
equals the current-limit trip level, the external MOSFET is turned off.
Gate Drive for External P-Channel MOSFET. EXT swings between V+ and GND.
Ground
The MAX1649/MAX1651 offer four main improvements
over prior solutions:
V+
5
C4
0.1 μ F
C1
100 μ F
1) The converters operate with miniature surface-mount
inductors, due to their 300kHz switching frequency.
MAX1649
MAX1651
CS
R1
0.05 Ω
6
P1
2) The current-limited PFM control scheme allows
greater than 90% efficiencies over a wide range of
load currents (10mA to 1.5A).
3) Dropout voltage has been reduced to less than
3
SHDN
EXT
7
Si9430 *
L1
OUTPUT
@ 1.5A
300mV for many applications.
4) The quiescent supply current is only 100μA.
4
REF
OUT
1
47 μ H **
PFM Control Scheme
FB
GND
The MAX1649/MAX1651 use a proprietary, current-limit-
C3
0.1 μ F
2
8
D1
NSQ03A02L
C2
330 μ F
ed PFM control scheme. As with traditional PFM con-
verters, the external power MOSFET is turned on when
the voltage comparator senses that the output is out of
regulation. However, unlike traditional PFM converters,
* SILICONIX SURFACE-MOUNT MOSFET
** SUMIDA CDRH125-470
Figure 1. Typical Application Circuit
_______________Detailed Description
The MAX1649/MAX1651 are BiCMOS, step-down,
switch-mode power-supply controllers that provide
adjustable and fixed outputs of 5V and 3.3V, respec-
tively. Their unique control scheme combines the
advantages of pulse-frequency-modulation (low supply
current) and pulse-width-modulation (high efficiency at
high loads). An external P-channel power MOSFET
allows peak currents in excess of 3A, increasing the
output current capability over previous PFM devices.
Figure 2 is the block diagram.
switching is accomplished through the combination of a
peak current limit and a pair of one-shots that set the
maximum switch on-time (32μs) and minimum switch
off-time (1.1μs). Once off, the off-time one-shot holds
the switch off for 1.1μs. After this minimum time, the
switch either 1) stays off if the output is in regulation, or
2) turns on again if the output is out of regulation.
The MAX1649/MAX1651 also limit the peak inductor cur-
rent, which allows them to run in continuous-conduction
mode and maintain high efficiency with heavy loads
(Figure 3). This current-limiting feature is a key compo-
nent of the control circuitry. Once turned on, the switch
stays on until either 1) the maximum on-time one-shot
turns it off (32μs later), or 2) the current limit is reached.
EXT swings from V+ to GND and provides the drive out-
put for an external P-channel power MOSFET.
6
_______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1649EVKIT | 功能描述:DC/DC 开关控制器 Evaluation Kit for the MAX649 MAX651 MAX652 and MAX1649 MAX1651 RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1649EVKIT-SO | 功能描述:DC/DC 开关控制器 3V or Adjustable High-Efficiency Low-Dropout Step-Down DC-DC Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX1649MJA | 功能描述:DC/DC 开关控制器 3V or Adjustable High-Efficiency Low-Dropout Step-Down DC-DC Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK |
| MAX164BCNG | 功能描述:模数转换器 - ADC 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 |
| MAX164BCNG+ | 功能描述:模数转换器 - ADC 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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