- 您现在的位置：买卖IC网 > PDF目录296470 > MAX8795A+ (MAXIM INTEGRATED PRODUCTS INC) 1.6 A SWITCHING REGULATOR, 1400 kHz SWITCHING FREQ-MAX, QCC32 PDF资料下载
参数资料
| 型号： | MAX8795A+ |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 稳压器 |
| 英文描述： | 1.6 A SWITCHING REGULATOR, 1400 kHz SWITCHING FREQ-MAX, QCC32 |
| 封装： | 5 X 5 MM, 0.80 MM HEIGHT, LEAD FREE, MO-220WHHD-2, TQFN-32 |
| 文件页数： | 9/24页 |
| 文件大小： | 387K |
| 代理商： | MAX8795A+ |
MAX8795A
TFT-LCD DC-DC Converter with
Operational Amplifiers
_
__
_
1
17
7
Considering the typical operating circuit, the maximum
load current (IMAIN(MAX)) is 500mA with a 14V output and
a typical input voltage of 5V. Choosing an LIR of 0.5 and
estimating efficiency of 85% at this operating point:
Using the circuit’s minimum input voltage (4.5V) and
estimating efficiency of 80% at that operating point:
The ripple current and the peak current are:
Output-Capacitor Selection
The total output voltage ripple has two components: the
capacitive ripple caused by the charging and discharging
of the output capacitance, and the ohmic ripple due to the
capacitor’s equivalent series resistance (ESR):
where IRIPPLE is the RIPPLE inductor current (see the
Inductor Selection section). For ceramic capacitors, the
output voltage ripple is typically dominated by
VRIPPLE(C). The voltage rating and temperature charac-
teristics of the output capacitor must also be considered.
Input-Capacitor Selection
The input capacitor (CIN) reduces the current peaks
drawn from the input supply and reduces noise injection
into the IC. A 22F ceramic capacitor is used in the typi-
cal applications circuit (Figure 1) because of the high
source impedance seen in typical lab setups. Actual
applications usually have much lower source impedance
since the step-up regulator often runs directly from the
output of another regulated supply. Typically, CIN can
be reduced below the values used in the typical applica-
tions circuit. Ensure a low-noise supply at IN by using
adequate CIN. Alternately, greater voltage variation can
be tolerated on CIN if IN is decoupled from CIN using an
RC lowpass filter (see R10 and C13 in Figure 1).
Rectifier Diode
The MAX8795A’s high switching frequency demands a
high-speed rectifier. Schottky diodes are recommended
for most applications because of their fast recovery time
and low forward voltage. In general, a 2A Schottky
diode complements the internal MOSFET well.
Output-Voltage Selection
The output voltage of the main step-up regulator can be
adjusted by connecting a resistive voltage-divider from the
output (VMAIN) to AGND with the center tap connected to
FB (see Figure 1). Select R2 in the 10k
to 50k range.
Calculate R1 with the following equation:
where VFB, the step-up regulator’s feedback set point,
is 1.233V. Place R1 and R2 close to the IC.
Loop Compensation
Choose RCOMP to set the high-frequency integrator
gain for fast transient response. Choose CCOMP to set
the integrator zero to maintain loop stability.
For low-ESR output capacitors, use the following equa-
tions to obtain stable performance and good transient
response:
To further optimize transient response, vary RCOMP in
20% steps and CCOMP in 50% steps while observing
transient-response waveforms.
R
VV
C
LI
C
VC
IR
COMP
IN
OUT
MAIN MAX
COMP
OUT
MAIN MAX
COMP
≈
××
×
≈
×
××
253
10
()
RR
V
MAIN
FB
12
1
=×
:
()
(
)
()
(
)
VV
V
I
C
VV
Vf
and
VI
R
RIPPLE
RIPPLE C
RIPPLE ESR
RIPPLE C
MAIN
OUT
MAIN
IN
MAIN OSC
RIPPLE ESR
PEAK ESR COUT
=+
≈
≈
I
VV
V
H
V
MHz
A
IA
A
RIPPLE
PEAK
=
×
≈
=+
≈
45
14
45
33
14
12
077
194
077
2
233
.(
.
)
..
.
I
AV
V
A
IN DCMAX
(,
)
.
..
.
=
×
≈
05
14
45
08
194
L
V
VV
A
MHz
H
=
×
≈
5
14
5
05
12
085
05
33
2
..
.
相关PDF资料 |
PDF描述 |
|---|---|
| MAX879CSA | IC LOGIC 16213 24-BIT FET BUS-EXCHANGE SWITCH -40+85C TSSOP-56 1500/REEL |
| MAX9851EVCMODU | MAX9851评估板/评估系统 |
| MAX9934FART+T | SPECIALTY ANALOG CIRCUIT, PBGA6 |
| MAX9950FCCB | SPECIALTY ANALOG CIRCUIT, PQFP64 |
| MAX9966BGCCQ+D | Quad, Low-Power, 500Mbps ATE Driver/Comparator |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX8795AETJ+ | 功能描述:直流/直流开关转换器 TFT-LCD DC/DC Converter 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 |
| MAX8795AETJ+C7P | 功能描述:显示驱动器和控制器 TFT-LCD DC/DC Converter RoHS:否 制造商:Panasonic Electronic Components 工作电源电压:2.7 V to 5.5 V 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:QFN-44 封装:Reel |
| MAX8795AETJ+T | 功能描述:LCD 驱动器 TFT-LCD DC/DC Converter RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
| MAX8795AEVKIT+ | 功能描述:电源管理IC开发工具 MAX8795A Eval Kit RoHS:否 制造商:Maxim Integrated 产品:Evaluation Kits 类型:Battery Management 工具用于评估:MAX17710GB 输入电压: 输出电压:1.8 V |
| MAX8795AGCJ/V+ | 功能描述:LCD 驱动器 TFT-LCD DC/DC Converter RoHS:否 制造商:Maxim Integrated 数位数量:4.5 片段数量:30 最大时钟频率:19 KHz 工作电源电压:3 V to 3.6 V 最大工作温度:+ 85 C 最小工作温度:- 20 C 封装 / 箱体:PDIP-40 封装:Tube |
发布紧急采购，3分钟左右您将得到回复。