參數(shù)資料
型號(hào)： MAX1885EUP
廠商： MAXIM INTEGRATED PRODUCTS INC
元件分類： 穩(wěn)壓器
英文描述： Fixed-Point Digital Signal Processor 256-BGA
中文描述： 2.05 A SWITCHING REGULATOR, 625 kHz SWITCHING FREQ-MAX, PDSO20
封裝： 4.40 MM, 1.10 MM HEIGHT, MO-153AC, TSSOP-20
文件頁(yè)數(shù)： 34/38頁(yè)
文件大小： 1051K
代理商： MAX1885EUP
M
Quad-Output TFT LCD DC-DC
Converters with Buffer
34
______________________________________________________________________________________
converter steps up the input voltage so that the linear
regulator will not drop out. Therefore, to guarantee that
the external pass transistor does not saturate, the step-
up converter
’
s output voltage must be set above the lin-
ear regulator
’
s output voltage plus the transistor
’
s
saturation rating (V
MAIN
≥
V
LDO
+ V
SAT
).
Power-Up Sequencing and Fault Protection
The MAX1778/MAX1880
–
MAX1885
’
s fault protection
cannot be activated until the power-up sequence is
successfully completed and the power ready output
goes low. Therefore, faults on the main output or posi-
tive charge-pump output could damage the controller
or external components. Additional fault protection may
be added as shown in Figure 10. The external MOSFET
and PNP transistor isolate the positive outputs during
startup. When the controller finishes the power-up
sequence, the power-ready output goes low, turning on
the PNP transistor. Any fault on the positive charge-
pump output will pull down the charge pump
’
s output
voltage and trigger the fault protection; otherwise, the
MOSFET
’
s gate slow charges. Once the MOSFET turns
on, any faults on the main step-up converter
’
s output
will pull down the main output voltage and trigger the
fault protection.
VCOM Buffer Startup
The VCOM buffer does not include soft-start. Therefore,
once the VCOM buffer turns on, it draws high surge
currents while charging the output capacitance. In
some applications, the buffer
’
s high startup surge
current could potentially trip the fault detection circuit,
forcing the controller to shut down. In these cases,
adding a soft-start resistive divider between SUPB and
BUFOUT reduces the startup surge current and voltage
drops associated with this load (Figure 11), as shown in
IN
SHDN
SYSTEM
POSITIVE
V
POS(SYS)
= 20V
STARTUP
POSITIVE
V
POS(START)
= 20V
INPUT
V
IN
= 3.3V
SUPP
LX
L1
6.8
μ
H
INPUT
V
IN
= 3.3V
C1
0.22
μ
F
C5
1.0
μ
F
C7
1.0
μ
F
Q2
Q3
C
OUT
(2) 3.3
μ
F
C4
0.1
μ
F
C
IN
4.7
μ
F
R10
100k
R
RDY
5.1k
R1
274k
R2
49.9k
R7
10k
FB
RDY
TGND
FBP
DRVP
GND
REF
FLTSET
INTG
PGND
C
REF
0.22
μ
F
MAX1778
C8
3.3
μ
F
SYSTEM MAIN
V
MAIN(SYS)
= 8V
STARTUP MAIN
V
MAIN(START)
= 8V
C10
0.1
μ
F
C6
0.1
μ
F
R8
100k
R3
750k
R4
49.9k
R9
30k
Figure 10. Power-Up Sequencing and Fault Protection;
相關(guān)PDF資料
PDF描述
MAX1778EUG Quad-Output TFT LCD DC-DC Converters with Buffer
MAX1880EUG Quad-Output TFT LCD DC-DC Converters with Buffer
MAX1881EUG Quad-Output TFT LCD DC-DC Converters with Buffer
MAX1882EUG Quad-Output TFT LCD DC-DC Converters with Buffer
MAX1779 32-Bit Digital Signal Controller with ROM 100-LQFP -40 to 125
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX1885EUP-T 功能描述:LCD 驅(qū)動(dòng)器 Quad-Output TFT LCD DC-DC Converter with Buffer RoHS:否 制造商:Maxim Integrated 數(shù)位數(shù)量:4.5 片段數(shù)量:30 最大時(shí)鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube
MAX1886ESA+ 制造商:Maxim Integrated Products 功能描述:HIGH-CURRENT VCOM DRIVE BUFFER - Rail/Tube
MAX1886EUK 制造商:Maxim Integrated Products 功能描述:HIGH-CURRENT VCOM DRIVE BUFFER - Rail/Tube
MAX1886EUK+T 功能描述:運(yùn)算放大器 - 運(yùn)放 RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
MAX1886EUK-T 功能描述:運(yùn)算放大器 - 運(yùn)放 RoHS:否 制造商:STMicroelectronics 通道數(shù)量:4 共模抑制比（最小值）:63 dB 輸入補(bǔ)償電壓:1 mV 輸入偏流（最大值）:10 pA 工作電源電壓:2.7 V to 5.5 V 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:QFN-16 轉(zhuǎn)換速度:0.89 V/us 關(guān)閉:No 輸出電流:55 mA 最大工作溫度:+ 125 C 封裝:Reel
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