- 您現(xiàn)在的位置：買賣IC網 > PDF目錄383334 > MAX1774EEI (MAXIM INTEGRATED PRODUCTS INC) Dual, High-Efficiency, Step-Down Converter with Backup Battery Switchover PDF資料下載
參數(shù)資料
| 型號： | MAX1774EEI |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Dual, High-Efficiency, Step-Down Converter with Backup Battery Switchover |
| 中文描述： | 3 A SWITCHING CONTROLLER, 1250 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | 0.150 INCH, 0.025 INCH PITCH, QSOP-28 |
| 文件頁數(shù)： | 11/21頁 |
| 文件大小： | 398K |
| 代理商： | MAX1774EEI |
M
Dual, High-Effic ienc y, S tep-Down
Converter with Bac kup Battery S witc hover
_______________________________________________________________________________________
11
Detailed Desc ription
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
S tep-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
PIN
QSOP
—
QFN
10
NAME
FUNCTION
LXB2
Backup Converter Switching Node. Connect LXB2 to LXB as close to the IC as possible.
13
11
BIN
Backup Batter y Inp ut. C onnect BIN to the outp ut of the b ackup b oost r eg ul ator Byp ass BIN w h a 10μF or
g eater cap aci or to GN D W hen the M AX 1774 i s i n b ackup m od e, BIN p ow er s the m ai n outp ut.
14
12
BKOFF
Backup D sab e Inp ut. D vi ng
BKO FF
b el ow + 0.5V d sab es the b ackup m od e. In b ackup m od e, the
d evi ce enter s shutd ow n w hen thi s p n i s p ul ed l ow
BKO FF
can b e d r ven fr om a d g al si g nal or can b e
used as a l ow b atter y d etector to d sab e the b ackup conver er w hen the b ackup b atter y i s l ow
15
13
ACI
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.
16
14
DBI
D ead Batter y Inp ut. C onnect D BI to the m ai n b atter y thr oug h a r esi sti ve voltage-divider. W hen D BI d op s
b el ow + 1.20V no AC ad ap er i s connected (
ACO
i s l ow b ut m ai n outp ut sti avai ab e)
BKU P
asser s.
17
15
LBI
Low-Battery Input. Connect LBI to the main battery through a r esi sti ve voltage-divider. When the
voltage at LBI drops below +1.20V,
LBO
asserts.
18
16
REF
Reference Voltage Output. Bypass REF to GND with a 0.22μF or greater capacitor.
—
17, 25,
29
N.C.
No Connection. Not Internally Connected.
19
18
FBM
Main Output Feedback. Connect FBM to a resistive voltage-divider to set main output voltage
between +1.25V to +5.5V.
20
19
CS+
Main Regulator High-Side Current-Sense Input. Connect the sense resistor between CS+ and CS-.
This voltage is used to set the current limit and to turn off the synchronous rectifier when the
inductor current approaches zero.
21
20
CS-
Main Regulator Low-Side Current-Sense Input. Connect CS- to the main output.
22
21
FBC
C or e Outp ut Feed b ack. C onnect FBC to a resistive voltage-divider to set cor e outp ut b etw een + 1.0V
to + 5.0V
23
24
25
26
27
28
22
23
24
26
27
28
GND
INC
ACO
LBO
INS
LXC
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
Pin Desc ription (c ontinued)
相關PDF資料 |
PDF描述 |
|---|---|
| MAX1774EMJ | 32-Bit Digital Signal Controller with ROM 100-LQFP -40 to 85 |
| MAX1775 | 32-Bit Digital Signal Controller with ROM 100-LQFP -40 to 125 |
| MAX1775EEE | 32-Bit Digital Signal Controller with ROM 100-LQFP -40 to 125 |
| MAX1776 | 32-Bit Digital Signal Controller with ROM 100-BGA MICROSTAR -40 to 85 |
| MAX1776EUA | 24V, 600mA Internal Switch, 100% Duty Cycle, Step-Down Converter |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1774EEI+ | 功能描述:直流/直流開關轉換器 Dual Step-Down w/Switchover RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| MAX1774EEI+T | 功能描述:直流/直流開關轉換器 Dual Step-Down w/Switchover RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| MAX1774EEI-T | 功能描述:直流/直流開關轉換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
| MAX1774EGJ | 制造商:Maxim Integrated Products 功能描述: |
| MAX1774EMJ | 功能描述:直流/直流開關轉換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風格:SMD/SMT |
發(fā)布緊急采購，3分鐘左右您將得到回復。