- 您现在的位置：买卖IC网 > PDF目录17412 > ADP1879-1.0-EVALZ (Analog Devices Inc)BOARD EVAL FOR ADP1879-1.0 PDF资料下载
参数资料
| 型号： | ADP1879-1.0-EVALZ |
| 厂商： | Analog Devices Inc |
| 文件页数： | 25/40页 |
| 文件大小： | 0K |
| 描述： | BOARD EVAL FOR ADP1879-1.0 |
| 标准包装： | 1 |
| 系列： | * |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页当前第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页
?? ????????
?? ???????? =
× ??? ?????????? 2 + ?? ???????? 2
1
Data Sheet
Ceramic capacitors are known to have low ESR. However, there
is a trade-off in using the popular X5R capacitor technology
because as much as 80% of its capacitance may be lost due to
derating as the voltage applied across the capacitor is increased
(see Figure 82). Although X7R series capacitors can also be
used, the available selection is limited to 22 μF maximum.
20
10
X7R (50V)
0
–10
–20
–30
–40
–50
ADP1878/ADP1879
Error Amplifier Output Impedance (Z COMP )
Assuming C C2 is significantly smaller than C COMP , C C2 can be
omitted from the output impedance equation of the error
amplifier. The transfer function simplifies to
and ?? ??????????
?? f ZERO = × ?? ????
where ?????????? , the 12 zero frequency, is set to be 1/4 th of the crossover
Error Amplifier Gain (G m )
–60
X5R (25V)
The error amplifier gain (transconductance) is
1
( ?? ? ?? )
?? ???? =
?? ??????
?? = 1 V ? V = ?? ?? × ?? ???? ×
× ?? ???????? × ?? ????????
1 + ?? × ?????? × ?? ??????
?? ???????????? = ?? ?? ×
1
?? ?????????? =
??
1
?? ???????? =
?? ???????? =
?? ?????????? × ? 1 2 + ( ?? ( ?? ?? + ?????? ) ?? ?????? ) 2 × 1 ×
??? ?????????? + ?? ???????? ? 1 2 + ( ?? × ?????? × ?? ?????? ) 2 ?? ??
?? ??????
1
×
1
?? ???????? =
–70
X5R (16V)
–80
10μF TDK 25V, X7R, 1210 C3225X7R1E106M
–90 22μF MURATA 25V, X7R, 1210 GRM32ER71E226KE15L
47μF MURATA 16V, X5R, 1210 GRM32ER61C476KE15L
–100
0 5 10 15 20 25 30
DC VOLTAGE (V DC )
Figure 82. Capacitance vs. DC Voltage Characteristics for Ceramic Capacitors
Electrolytic capacitors satisfy the bulk capacitance requirements
for most high current applications. However, because the ESR of
electrolytic capacitors is much higher than that of ceramic capaci-
tors, mount several MLCCs in parallel with the electrolytic
capacitors to reduce the overall series resistance.
COMPENSATION NETWORK
require Type II compensation. To determine the component
values needed for compensation (resistance and capacitance
values), it is necessary to examine the overall loop gain (H) of the
converter at the unity-gain frequency (f SW /10) when H = 1 V/V:
?? ?????? transfer each variable at high frequency enables the unity-
Examining function to be simplified to provide expressions
for the R COMP and C COMP component values.
Output Filter Impedance (Z FILT )
Examining the transfer function of the filter at high frequencies
simplifies to
1 + ?? ?? 2πf ?????? ) ?? ).
at the crossover frequency ( (s ?? = + CROSS ?????? ESR is the equivalent
series resistance of the output capacitors.
G m = 500 μA/V (μs)
Current-Sense Loop Gain (G CS )
The current-sense loop gain is
A CS (V/V) ?? ???? × ?? ????
where: is programmable for 3 V/V, 6 V/V, 12 V/V, and 24 V/V
(see the Programming Resistor (RES) Detect Circuit and Valley
Current-Limit Setting sections).
R ON is the channel impedance of the low-side MOSFET.
Crossover Frequency
The crossover frequency is the frequency at which the overall
loop (system) gain is 0 dB (H = 1 V/V). It is recommended for
current-mode converters, such as the ADP1878 , that the user set
the crossover frequency between 1/10 th and 1/15 th of the switching
frequency.
12 ????
The relationship between C COMP and f ZERO (zero frequency) is as
follows:
2 ?? × is set × ?? 1/4 th of
The zero frequency ?? ???????? to ???????? the crossover frequency.
Combining all of the above parameters results in
2 2
?? ?????? ?? ?? ????
where ESR is ?? the equivalent series resistance of the output
capacitors.
2 × ?? × ?? ???????? × ?? ????????
Rev. B | Page 25 of 40
相关PDF资料 |
PDF描述 |
|---|---|
| LM4040D30QDBZR | IC VREF SHUNT PREC 3V SOT-23-3 |
| GCC28DCAN | CONN EDGECARD 56POS R/A .100 SLD |
| GBM24DTMN-S189 | CONN EDGECARD 48POS R/A .156 SLD |
| SS2P3HE3/84A | DIODE SCHOTTKY 2A 30V SMP |
| GCC28DCAH | CONN EDGECARD 56POS R/A .100 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| ADP1879ACPZ-0.3-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 14LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| ADP1879ACPZ-0.6-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 14LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| ADP1879ACPZ-1.0-R7 | 功能描述:IC REG CTRLR BUCK PWM CM 14LFCSP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| ADP1880ACPZ-R7 | 制造商:Analog Devices 功能描述: |
| ADP1882 | 制造商:AD 制造商全称:Analog Devices 功能描述:Synchronous Current-Mode with Constant On-Time,PWM Buck Controller |
发布紧急采购，3分钟左右您将得到回复。