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参数资料
| 型号： | MAX1956ETI+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 20/22页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| PWM 型： | 电压模式 |
| 输出数： | 2 |
| 频率 - 最大： | 660kHz |
| 占空比： | 97% |
| 电源电压： | 1.6 V ~ 5.5 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： | -40°C ~ 85°C |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
1.6V to 5.5V Input, 0.5% Accurate, Dual
180° Out-of-Phase Step-Down Controllers
another high-frequency pole (f PHF ) to the error-amplifier
response. This pole should be greater than 100 times
the error-amplifier zero frequency in order to have neg-
f ZESR =
1
2 π × C OUT × ESR
=
1
2 π × 1360 × 10 - 6 × 0 . 004
ligible impact on the phase margin. This pole also
should be less than half the switching frequency for
effective decoupling:
100f ZEA < f PHF < 0.5f SW
Select a value for f PHF in the range given above, and
then solve for C F using the following equation:
= 29 . 3 kHz
Pick the crossover frequency (f C ) in the range f ZESR <
f C < f SW /5:
29.3kHz < f C < 120kHz
Select f C = 100kHz (this meets the criteria above), and
the bandwidth is high enough for good transient
C F =
1
2 π × R C × f PHF
response.
The power-modulator gain at f C is:
V IN ( f PMOD ) 2
G MOD ( fc ) = ×
=
×
= 0 . 0477
With two converters in proximity, there is a potential for
crosstalk between the converters. Crosstalk can be
managed by board layout and high-frequency filtering,
which can be inserted by adding a high-frequency pole
in the feedback network. To do so and minimize effect
on phase margin, add capacitors C7 and C8 (Figure 5)
with a pole frequency of:
f PFB2 = (R4 + R6) / 2 π x R4 x R6 x C7)
V RAMP f ZESR × f C
3 ( 7 . 879 kHz ) 2
1 29 . 3 kHz × 100 kHz
Pick R X = 8.06k ? , then R Y = 10k ? (see the Setting the
Output Voltage section).
= 17 . 6 k ?
f PFB1 = (R2 + R3) / (2 π x R2 x R3 x C8)
Set the poles above ~4 to 5 times the crossover fre-
quency.
Below is a numerical example to calculate the compen-
sation values used in the typical application circuit of
R C =
=
V OUT
g mEA × G MOD ( fc ) × V FB
1 . 8
0 . 002 × 0 . 8 × . 0636
Figure 5:
V IN = 3V (the midpoint of the input voltage range)
Select R C = 18k ? (nearest standard resistor value).
V RAMP = 1V
V OUT = 1.8V
C C =
5
2 π × R C × f PMOD
=
5
2 π × 18 k ? × 7 . 879 kHz
= 5620 pF
V FB = 0.8V
I OUT(MAX) = 25A
C OUT = 2 x 680μF
ESR = 0.008 ? / 2 = 0.004 ?
L = 0.3μH
Select C C = 6800pF (rounded up to the next standard
capacitor value).
Select f PHF in the range 100f ZEA < f PHF < 0.5f SW . Hence:
157.6kHz < f PHF < 300kHz
Select f PHF = 250kHz, and then solve for C F :
g mEA = 2mS
f SW = 600kHz
C F =
1
2 π × R C × f PHF
=
1
2 π × 18 k ? × 250 kHz
= 33 pF
f PMOD =
1
2 π × L × C OUT
A summary of feedback divider and compensation
components follows:
=
1
2 π × 0 . 3 × 10 - 6 × 1360 × 10 - 6
= 7 . 879 kHz
R X = 8.06k ?
R Y = 10k ?
R C = 18k ?
C C = 6800pF
C F = 33pF
20
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相关代理商/技术参数 |
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|---|---|
| MAX1957EUB | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1957EUB+ | 功能描述:电流型 PWM 控制器 High-f Current-Mode PWM Buck Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1957EUB+T | 功能描述:电流型 PWM 控制器 High-f Current-Mode PWM Buck Controller RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX1957EUB-T | 功能描述:电流型 PWM 控制器 RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| MAX19586ETN | 功能描述:模数转换器 - ADC RoHS:否 制造商:Texas Instruments 通道数量:2 结构:Sigma-Delta 转换速率:125 SPs to 8 KSPs 分辨率:24 bit 输入类型:Differential 信噪比:107 dB 接口类型:SPI 工作电源电压:1.7 V to 3.6 V, 2.7 V to 5.25 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-32 |
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