- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄383334 > MAX1885 (Maxim Integrated Products, Inc.) Quad-Output TFT LCD DC-DC Converters with Buffer PDF資料下載
參數(shù)資料
| 型號(hào)： | MAX1885 |
| 廠商： | Maxim Integrated Products, Inc. |
| 元件分類(lèi)： | DC/DC變換器 |
| 英文描述： | Quad-Output TFT LCD DC-DC Converters with Buffer |
| 中文描述： | 四路輸出、TFT LCD DC-DC轉(zhuǎn)換器，帶有緩沖器 |
| 文件頁(yè)數(shù)： | 31/38頁(yè) |
| 文件大小： | 1051K |
| 代理商： | MAX1885 |
第1頁(yè)第2頁(yè)第3頁(yè)第4頁(yè)第5頁(yè)第6頁(yè)第7頁(yè)第8頁(yè)第9頁(yè)第10頁(yè)第11頁(yè)第12頁(yè)第13頁(yè)第14頁(yè)第15頁(yè)第16頁(yè)第17頁(yè)第18頁(yè)第19頁(yè)第20頁(yè)第21頁(yè)第22頁(yè)第23頁(yè)第24頁(yè)第25頁(yè)第26頁(yè)第27頁(yè)第28頁(yè)第29頁(yè)第30頁(yè)當(dāng)前第31頁(yè)第32頁(yè)第33頁(yè)第34頁(yè)第35頁(yè)第36頁(yè)第37頁(yè)第38頁(yè)
M
Quad-Output TFT LCD DC-DC
Converters with Buffer
______________________________________________________________________________________
31
Input-Output (Dropout) Voltage and Startup
A linear regulator
’
s minimum input-to-output voltage dif-
ferential (dropout voltage) determines the lowest use-
able supply voltage. Because the MAX1778/
MAX1881/MAX1883/MAX1884 use an internal PNP
transistor (or external NPN transistor), their dropout
voltage is a function of the transistor
’
s collector-to-emit-
ter saturation voltage (see
Typical Operating
Characteristics
). The linear regulator
’
s quiescent cur-
rent increases when in dropout.
The internal linear regulator will try to start up once its
supply voltage (V
SUPL
) exceeds 4V. When the linear
regulator powers up, the linear regulator may be in
dropout if the linear regulator
’
s output set voltage is
higher than its input supply voltage. Therefore, during
this brief period, the linear regulator draws additional
supply current until the input supply voltage exceeds
the output set voltage plus the pass transistor
’
s satura-
tion voltage (V
LDO(SET
) + V
CE(SAT)
).
VCOM Buffer (Operational
Transconductance Amplifier)
Buffer Output Voltage and Capacitor Selection
The positive input (BUF+) features dual mode opera-
tion. Connect BUF+ to GND for the preset VSUPB/2
output voltage, set by an internal 50% resistive-divider.
Adjust the amplifier
’
s output voltage by connecting a
voltage-divider from SUPB to BUF+ to GND (Figure 6).
Select R12 in the 10k
to 100k
range. Calculate R11
with the following equation:
where V
SUPB
may range from 4.5V to 13V, and V
BUF+
may range from 1.2V to (V
SUPB
- 1.2V). Connect a mini-
mum 1μF ceramic capacitor from BUFOUT to ground.
PC Board Layout and Grounding
Careful PC board layout is extremely important for
proper operation. Follow the following guidelines for
good PC board layout:
1) Place the main step-up converter output diode and
output capacitor less than 0.2in (5mm) from the LX
and PGND pins with wide traces and no vias.
2) Separate analog ground and power ground. The
ground connections for the step-up converter
’
s and
charge pump
’
s input and output capacitors should
be connected to the power ground plane. The lin-
ear regulator
’
s and VCOM buffer
’
s input and output
capacitors should be connected to a separate
power-ground path, star-connected to the PGND
pin to minimize voltage drops. When using multi-
layer boards, the top layer should contain the boost
R
R
V
V
SUPB
BUF
11
12
1
-
=
+
IN
SHDN
LDOOUT
LX
L1
6.8
μ
H
INPUT
V
IN
= 3.3V
C1
0.22
μ
F
C
OUT
(2) 4.7
μ
F
C
IN
4.7
μ
F
R1
274k
R2
49.9k
FB
GND
FBL
REF
Q1
INTG
PGND
C
REF
0.22
μ
F
MAX1778
MAX1883
(MAX1881)*
(MAX1884)*
R3
49.9k
R4
49.9k
C
LDO
1
μ
F
C3
0.01
μ
F
C2
0.01
μ
F
C
LDOOUT
4.7
μ
F
C
LDOIN
1
μ
F
R5
1.5k
MAIN
V
MAIN
= 8V
LDO
V
LDO
= 2.5V
SUPL
Figure 7. External Linear Regulator
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX1883EUP | Replaced by TMS320C6211B : Fixed-Point Digital Signal Processor 256-BGA 0 to 0 |
| MAX1884EUP | Fixed-Point Digital Signal Processor 256-BGA |
| MAX1885EUP | Fixed-Point Digital Signal Processor 256-BGA |
| MAX1778EUG | Quad-Output TFT LCD DC-DC Converters with Buffer |
| MAX1880EUG | Quad-Output TFT LCD DC-DC Converters with Buffer |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX1885EUP | 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 |
| 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 |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。