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| 型号： | MAX1774EEI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 11/21页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ DL 28QSOP |
| 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： | 2 |
| 输出电压： | 1 V ~ 5.5 V |
| 输入电压： | 2.7 V ~ 28 V |
| 频率 - 开关： | 1.25MHz |
| 电流 - 输出： | 1.5A，2A |
| 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： | 28-SSOP（0.154"，3.90mm 宽） |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 28-QSOP |
Dual, High-Efficiency, Step-Down
Converter with Backup Battery Switchover
Pin Description (continued)
PIN
QSOP
—
13
QFN
10
11
NAME
LXB2
BIN
FUNCTION
Backup Converter Switching Node. Connect LXB2 to LXB as close to the IC as possible.
Backup Battery Input. Connect BIN to the output of the backup boost regulator. Bypass BIN with a 10μF or
greater capacitor to GND. When the MAX1774 is in backup mode, BIN powers the main output.
Backup Disable Input. Driving BKOFF below +0.5V disables the backup mode. In backup mode, the
14
12
BKOFF
device enters shutdown when this pin is pulled low. BKOFF can be driven from a digital signal or can be
used as a low battery detector to disable the backup converter when the backup battery is low.
15
16
17
18
—
19
13
14
15
16
17, 25,
29
18
ACI
DBI
LBI
REF
N.C.
FBM
AC Adapter Low-Voltage Detect Input. Connect to adapter DC input. When the voltage at ACI falls
below the voltage at INS plus +0.22V, ACO asserts.
Dead Battery Input. Connect DBI to the main battery through a resistive voltage-divider. When DBI drops
below +1.20V, no AC adapter is connected ( ACO is low, but main output still available), BKUP asserts.
Low-Battery Input. Connect LBI to the main battery through a resistive voltage-divider. When the
voltage at LBI drops below +1.20V, LBO asserts.
Reference Voltage Output. Bypass REF to GND with a 0.22μF or greater capacitor.
No Connection. Not Internally Connected.
Main Output Feedback. Connect FBM to a resistive voltage-divider to set main output voltage
between +1.25V to +5.5V.
Main Regulator High-Side Current-Sense Input. Connect the sense resistor between CS+ and CS-.
20
19
CS+
This voltage is used to set the current limit and to turn off the synchronous rectifier when the
inductor current approaches zero.
21
22
23
24
25
26
27
28
20
21
22
23
24
26
27
28
CS-
FBC
GND
INC
ACO
LBO
INS
LXC
Main Regulator Low-Side Current-Sense Input. Connect CS- to the main output.
Core Output Feedback. Connect FBC to a resistive voltage-divider to set core output between +1.0V
to +5.0V.
Analog Ground
Core Supply Input
Low AC Output. Open drain ACO asserts when ACI falls below the main output voltage plus 0.22V.
Open-Drain Low-Battery Output. LBO asserts when LBI falls below +1.20V.
Power-Supply Input Voltage Sense Input. Connect INS to the power-supply input voltage.
Core Converter Switching Node
Detailed Description
The MAX1774 dual step-down DC-DC converter is
designed to power PDA, palmtop, and subnotebook
computers. Normally, these devices require two sepa-
rate power supplies–one for the processor and another
higher voltage supply for the peripheral circuitry. The
MAX1774 provides an adjustable +1.25V to +5.5V main
output designed to power the peripheral circuitry of
PDAs and similar devices. The main output delivers up
to 2A output current. The lower voltage core converter
has an adjustable +1.0V to +5.0V output, providing up
to 1.5A output current. Both regulators utilize a propri-
etary regulation scheme allowing PWM operation at
medium to heavy loads, and automatically switch to
pulse skipping at light loads for improved efficiency.
Under low-battery conditions, the MAX1774 enters
backup mode, making use of a low-voltage backup
battery and a step-up regulator to power the output.
Figure 1 is the MAX1774 typical application circuit.
Operating Modes for the
Step-Down Converters
When delivering low output currents, the MAX1774 oper-
ates in discontinuous conduction mode. Current through
the inductor starts at zero, rises as high as the minimum
current limit (I MIN ), then ramps down to zero during
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1774EGJ | 制造商:Maxim Integrated Products 功能描述: |
| MAX1774EMJ | 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 |
| MAX1774EVKIT | 功能描述:直流/直流开关转换器 Evaluation Kit for the MAX1774 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 |
| MAX1775EEE | 功能描述:直流/直流开关转换器 Dual-Out Step-Down for PDA/Palmtop 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 |
| MAX1775EEE+ | 功能描述:直流/直流开关转换器 Dual-Out Step-Down for PDA/Palmtop 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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