- 您现在的位置：买卖IC网 > PDF目录13119 > MAX1518BETJ+ (Maxim Integrated Products)IC DC-DC CONV TFT-LCD 32-TQFN PDF资料下载
参数资料
| 型号： | MAX1518BETJ+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 19/25页 |
| 文件大小： | 0K |
| 描述： | IC DC-DC CONV TFT-LCD 32-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 应用： | 转换器，TFT，LCD |
| 输入电压： | 2.6 V ~ 6.5 V |
| 输出数： | 1 |
| 输出电压： | 2.6 V ~ 13 V |
| 工作温度： | -40°C ~ 100°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 32-WFQFN 裸露焊盘 |
| 供应商设备封装： | 32-TQFN-EP（5x5） |
| 包装： | 管件 |
TFT-LCD DC-DC Converter with
Operational Amplifiers
V RIPPLE ( C ) ≈ MAIN ? MAIN IN ? , and
Output-Capacitor Selection
The total output voltage ripple has two components: the
capacitive ripple caused by the charging and discharg-
ing of the output capacitance, and the ohmic ripple due
to the capacitor’s equivalent series resistance (ESR).
V RIPPLE = V RIPPLE ( C ) + V RIPPLE ( ESR )
I ? V ? V ?
C OUT ? V MAIN f OSC ?
V RIPPLE ( ESR ) ≈ I PEAK R ESR ( COUT )
where I PEAK is the peak inductor current (see the
Inductor Selection section). For ceramic capacitors, the
output voltage ripple is typically dominated by
V RIPPLE(C) . The voltage rating and temperature charac-
teristics of the output capacitor must also be considered.
Input-Capacitor Selection
The input capacitor (C IN ) reduces the current peaks
drawn from the input supply and reduces noise injec-
where V FB , the step-up regulator’s feedback set point,
is 1.236V. Place R1 and R2 close to the IC.
Generating Output Voltages >13V
The maximum output voltage of the step-up regulator is
13V, which is limited by the absolute maximum rating of
the internal power MOSFET. To achieve higher output
voltages, an external n-channel MOSFET can be cascod-
ed with the internal FET (Figure 8). Since the gate of the
external FET is biased from the input supply, use a logic-
level FET to ensure that the FET is fully enhanced at the
minimum input voltage. The current rating of the FET
needs to be higher than the IC’s internal current limit.
Loop Compensation
Choose R COMP to set the high-frequency integrator
gain for fast transient response. Choose C COMP 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:
tion into the IC. A 22μF ceramic capacitor is used in the
Typical 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, C IN can be reduced below the values used in
R COMP ≈
C COMP ≈
315 × V IN × V OUT × C OUT
L × I MAIN ( MAX )
V OUT × C OUT
10 × I MAIN ( MAX ) × R COMP
n POS = GON DROPOUT MAIN
R 1 = R 2 × ? MAIN ? 1 ?
the Typical Applications Circuit. Ensure a low-noise
supply at IN by using adequate C IN . Alternately,
greater voltage variation can be tolerated on C IN if IN is
decoupled from C IN using an RC lowpass filter (see
R10 and C18 in Figure 1).
Rectifier Diode
The MAX1518B’s high switching frequency demands a
high-speed rectifier. Schottky diodes are recommend-
ed 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 (V MAIN ) to AGND with the center tap connect-
ed to FB (see Figure 1). Select R2 in the 10k ? to 50k ?
range. Calculate R1 with the following equation:
? V ?
? V FB ?
To further optimize transient response, vary R COMP in
20% steps and C COMP in 50% steps while observing
transient-response waveforms.
Charge Pumps
Selecting the Number of Charge-Pump Stages
For highest efficiency, always choose the lowest num-
ber of charge-pump stages that meet the output
requirement. Figures 9 and 10 show the positive and
negative charge-pump output voltages for a given
V MAIN for one-, two-, and three-stage charge pumps.
The number of positive charge-pump stages is given by:
V + V ? V
V MAIN ? 2 × V D
where n POS is the number of positive charge-pump
stages, V GON is the gate-on linear-regulator REG P out-
put, V MAIN is the main step-up regulator output, V D is
the forward-voltage drop of the charge-pump diode,
and V DROPOUT is the dropout margin for the linear reg-
ulator. Use V DROPOUT = 0.3V.
______________________________________________________________________________________
19
相关PDF资料 |
PDF描述 |
|---|---|
| AMM11DRAH | CONN EDGECARD 22POS .156 R/A |
| MAX8810AETM+ | IC CNTRLR PWM W/MOSFET 48TQFN |
| A8287SLBTR-T | IC LNB SUPPLY/VOLTAGE REG 24SOIC |
| 1782-15J | COIL RF .62UH MOLDED UNSHIELDED |
| VI-J6X-CX | CONVERTER MOD DC/DC 5.2V 75W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX1518BETJ+ | 功能描述:LCD 驱动器 TFT-LCD DC-DC Conv w/Op Amps 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 |
| MAX1518BETJ+T | 功能描述:LCD 驱动器 TFT-LCD DC-DC Conv w/Op Amps 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 |
| MAX1518ETJ | 功能描述:LCD 驱动器 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 |
| MAX1518ETJ+ | 功能描述:LCD 驱动器 TFT-LCD DC-DC Conv w/Op Amps 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 |
| MAX1518ETJ+T | 功能描述:LCD 驱动器 TFT-LCD DC-DC Conv w/Op Amps 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。