收藏本站
4V to 72V Input LDOs with Boost Preregulator
R 1 = R 2 × ? BSOUT ? 1 ?
Setting the Boost
Output Voltage (V BSOUT )
The MAX5092_/MAX5093_ feature Dual Mode? opera-
tion for the internal boost converter output voltage.
These devices operate in a preset output-voltage mode
or an adjustable output-voltage mode. In preset mode,
internal trimmed feedback resistors set V BSOUT to a
fixed 7V. Select the preset mode by directly connecting
BSFB to SGND (Figures 4 and 5). Ensure a low-imped-
ance path between BSFB and SGND to limit the tran-
sient at BSFB to below 100mV. In adjustable mode,
connect BSFB to the center tap of an external resistor-
divider connected between BSOUT and SGND to pro-
gram V BSOUT (Figures 6 and 7). Program (V BSOUT <
V OUT + V BST_DIS ) for lower V BSOUT ripple. Note that
the current drawn by the resistor-divider at BSOUT
adds to the quiescent current and the shutdown current
of the IC. Use the resistor-divider only if V BSOUT is
required to be significantly different than 7V. Select
499k Ω or lower resistance value for the bottom resistor
(R2) of the divider connected to SGND. The top resistor
(R1) value is calculated as:
? V ?
? V BSFB ?
Schottky Diode Selection (MAX5093_)
The MAX5093_ requires an external diode connected
between LX and BSOUT (Figures 5 and 7). Proper
selection of an external diode can offer a lower forward-
voltage drop and a higher reverse-voltage handling
capability. Since the high switching frequency of the IC
demands a high-speed rectifier, Schottky diodes are
recommended for most applications because of their
fast recovery time and low forward-voltage drop.
Ensure that the diode’s peak current rating is greater
than or equal to the peak current limit of internal boost
converter MOSFET. A diode average forward current
rating of at least 1A is recommended. Additionally, the
diode reverse breakdown voltage must be greater than
the worst-case load-dump-condition voltage.
CT Capacitor Selection
The MAX5092_/MAX5093_ contain an open-drain
power-on-reset output ( RESET ) that indicates when the
LDO output voltage (V OUT ) is out of regulation. When
V OUT rises above 92% of the nominal output voltage,
RESET goes high impedance after a user-programma-
ble time delay. This time duration is programmable by a
capacitor (C CT ) from CT to SGND (Figures 4–7). For a
chosen RESET active timeout period (t DELAY ), calculate
the required capacitor value as:
where V BSFB is the regulation voltage at BSFB (1.24V
typ) and V BSOUT is the desired output voltage for
BSOUT.
C CT =
2 × 10 ? 6 × t DELAY
1 . 24
R 4 = R 5 × ? OUT ? 1 ?
Setting the LDO Output Voltage (V OUT )
The LDO output voltage is also Dual Mode (preset and
adjustable). Preset mode is selected by connecting
SET to SGND (Figures 4 and 5). In preset mode, V OUT
regulates to 3.3V (MAX5092A/MAX5093A) or 5V
(MAX5092B/MAX5093B) by internal trimmed feedback
resistors. Adjustable mode is selected by connecting
SET to the center tap of an external resistor-divider
connected between OUT and SGND (Figures 6 and 7).
Note that the current drawn by the resistor-divider at
OUT adds to the quiescent current of the LDO. Use the
resistor-divider only if V OUT is required to be signifi-
cantly different than the preset voltage. Select 100k Ω or
lower value for the bottom resistor (R5) of the divider
connected to SGND. The top resistor (R4) value is cal-
culated as:
? V ?
? V SET ?
where V SET is the regulation voltage at SET (1.24V typ)
and V OUT is the desired output voltage for the LDO
output.
When V OUT drops below 90% of the LDO output regula-
tion voltage, a 5mA pulldown current from CT to SGND
discharges C CT . The time required to discharge CT
determines the delay necessary to pull RESET low. This
delay provides glitch immunity to the RESET function.
The glitch immunity delay is directly proportional to the
CT capacitor and is approximately 70μs for a 0.1μF
capacitor at CT.
Dual Mode is a trademark of Maxim Integrated Products, Inc.
______________________________________________________________________________________
19
发布紧急采购，3分钟左右您将得到回复。

采购需求

(若只采购一条型号，填写一行即可)

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

发布成功！您可以继续发布采购。也可以进入我的后台，查看报价

*型号 *数量 厂商 批号 封装
添加更多采购

我的联系方式

*
*
*
相关PDF资料
MAX620EWN IC DVR QUAD HISIDE MOSFET 18SOIC
MAX626CPA+ IC DRIVER MOSFET DUAL 8-DIP
MAX662EVKIT-SO EVAL KIT FOR MAX662
MAX6947ATE+T IC LED DRIVER LINEAR 16-TQFN
MAX6948BGWA+T IC LED DVR PWM GPIO 25WLP
MAX6964ATG+T IC LED DRIVER LINEAR 24-TQFN
MAX6965ATE+T IC LED DRIVER LINEAR 16-TQFN
MAX6967ATE+ IC LED DRIVER LINEAR 16-TQFN
相关代理商/技术参数
MAX5093 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:4V to 72V Input LDOs with Boost Preregulator
MAX5093AATE+ 功能描述:低压差稳压器 - LDO 4V to 72V LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX5093AATE+T 功能描述:低压差稳压器 - LDO 4V to 72V LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX5093BATE+ 功能描述:低压差稳压器 - LDO 4V to 72V LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX5093BATE+T 功能描述:低压差稳压器 - LDO 4V to 72V LDO RoHS:否 制造商:Texas Instruments 最大输入电压:36 V 输出电压:1.4 V to 20.5 V 回动电压（最大值）:307 mV 输出电流:1 A 负载调节:0.3 % 输出端数量: 输出类型:Fixed 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-20
MAX5094A 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:High-Performance, Single-Ended, Current-Mode PWM Controllers
MAX5094AASA 功能描述:电流型 PWM 控制器 Single-Ended 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
MAX5094AASA+ 功能描述:电流型 PWM 控制器 Single-Ended 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