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| 型号： | MAX1974EUB+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/15页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 1A 10UMAX |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 50 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 0.75 V ~ 5.5 V |
| 输入电压： | 2.6 V ~ 5.5 V |
| PWM 型： | 电流模式 |
| 频率 - 开关： | 1.4MHz |
| 电流 - 输出： | 1A |
| 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： | 10-TFSOP，10-MSOP（0.118"，3.00mm 宽） |
| 包装： | 管件 |
| 供应商设备封装： | 10-µMAX |
Smallest 1A, 1.4MHz Step-Down Regulators
Voltage Margining and Shutdown
A voltage-margining feature is provided on the
Table 1. CTL_ Input Functions (MAX1973)
MAX1973 to shift the output voltage up or down by 4%.
Voltage margining is useful for the automatic testing of
systems at high and low supply conditions to find
potential failures. See Table 1 for the MAX1973 voltage
margining and shutdown truth table.
A shutdown feature is included on both the MAX1973
and the MAX1974. Shutdown turns off the IC and
reduces the supply current about 0.1μA. For the
MAX1974, drive ON high for normal operation, or low
for shutdown. For the MAX1973, drive both CTL1 and
CTL2 high for normal operation, or drive both low for
CTL1
GND
GND
IN
IN
CTL2
GND
IN
GND
IN
FUNCTION
Shutdown
Positive voltage margining,
regulation voltage increased 4% from
normal operation
Negative voltage margining,
regulation voltage lowered 4% from
normal operation
Normal operation
shutdown. For a simple enable/shutdown function with
no voltage margining on the MAX1973, connect CTL1
Table 2. Preset Output Voltages
to CTL2 and drive as one input.
Power-OK Output (POK)
FBSEL
OUTPUT VOLTAGE
MAX1973 MAX1974
A power-OK output (POK) is provided on the MAX1974.
This is an open-drain output indicating when the output
voltage is in regulation. If the output voltage falls below
90% of its nominal value, POK goes low. POK remains
low until the output voltage rises to 92.5% of its nominal
GND
IN
Not Connected
1.8V
2.5V
Adjustable down
to 1.25V
1V
1.5V
Adjustable down to
0.75V
value. At that point, POK goes high impedance. To use
POK as a logic output, connect a 10k ? to 100k ? pullup
resistor from POK to the power supply of the logic
receiving the POK signal. POK continues to function in
shutdown or UVLO. Note that a minimum voltage of 1V
at IN is required to ensure that POK provides a valid
output. When V IN drops to zero, POK is high imped-
ance. See the Typical Operating Characteristics.
Applications Information
Output Voltage Selection
The output voltage can be set to one of two preset val-
ues, or can be set by an external resistor-divider. For
preset output voltages, connect FB to the output as
shown in Figures 2 and 3. Connect FBSEL to GND or IN
to select the desired preset output voltage (see Table 2).
To set the output voltage to a value other than the preset
values, FBSEL is not connected, and FB is connected to
a voltage-divider as shown in Figures 4 and 5. Select a
value for R2 in the 1k ? to 22k ? range, and then calcu-
late the value of R1 from the following equation:
For the MAX1973, V FB = 1.25V, allowing its output to be
set down to 1.25V. For the MAX1974, V FB = 0.75V,
allowing its output to be set down to 0.75V
The MAX1973/MAX1974 PWM circuitry is capable of a
stable minimum duty cycle of 17%. This limits the mini-
mum output voltage that can be generated to 0.17 ?
V IN . Instability may result for V IN /V OUT ratios below 0.17.
Inductor Selection
A 2.2μH to 4.7μH inductor with a saturation current of at
least 1.25A is recommended for full-load (1mA) applica-
tions. For lower load currents, the inductor current rating
can be reduced. For most applications, use an inductor
with a current rating 1.25 times the maximum required
output current. For best efficiency, the inductor ’ s DC
resistance should be as small as possible. See Table 3
for recommended inductors and manufacturers.
For most designs, the inductor value (L INIT ) can be
derived from the following equation:
R 1 = R 2 × ? OUT ? 1 ?
? V ?
? V FB ?
L INIT =
V OUT ( V IN ? V OUT )
V IN × LIR × I OUT ( MAX ) × f SW
______________________________________________________________________________________
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1974EUB+ | 功能描述:直流/直流开关调节器 1A 1.4MHz Step-Down Regulator 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 |
| MAX1974EUB+T | 功能描述:直流/直流开关调节器 1A 1.4MHz Step-Down Regulator 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 |
| MAX1974EUB-G05 | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1974EUB-T | 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 |
| MAX1974EUB-TG05 | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
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