参数资料
型号: ISL95210EVAL1Z
厂商: Intersil
文件页数: 11/20页
文件大小: 0K
描述: EVALUATION BOARD FOR ISL95210
标准包装: 1
主要目的: DC/DC,步降
输出及类型: 1,非隔离
输出电压: 1.2V
电流 - 输出: 10A
输入电压: 5V
稳压器拓扑结构: 降压
频率 - 开关: 800kHz
板类型: 完全填充
已供物品: 板,文档
已用 IC / 零件: ISL95210
ISL95210
Theory of Operation
The following sections will provide a detailed description of the
inner workings of the ISL95210 10A integrated FET regulator.
Start -Up
The ISL95210 will not respond to any logic inputs until VCC and
Output Voltage Programming
The highly integrated nature of the ISL95210 simplifies design
and reduces component count. The VSEL0 and VSEL1 pins are
3-state logic inputs to an integrated DAC that controls the output
voltage set point as prescribed in Table 1.
TABLE 1. DAC CONTROLLED OUTPUT VOLTAGE SETTINGS
PVCC are above the power-on reset (POR) level as described in
the “Electrical Specifications” table on page 5. Once the POR
condition is achieved, the ISL95210 will then acknowledge the
states of its logic inputs. If the EN pin is pulled above the rising
threshold, the regulator is commanded on and the soft-start
sequence is initiated.
During soft-start, the programmed output voltage set point is
determined by the logic states of VSEL0, VSEL1, MPCT and MSEL.
The output then ramps digitally to the regulation voltage in
2.5mV/μs steps. Once the output voltage achieves regulation,
the power-good monitor output (PGOOD) is toggled high to the
voltage provided on the PG_IN pin. Figure 25 illustrates the ideal
soft-start behavior.
VSEL1
0
0
0
FLOAT
FLOAT
FLOAT
1
1
1
VSEL0
0
FLOAT
1
0
FLOAT
1
0
FLOAT
1
VOUT (V)
0.600
0.750
0.900
1.000
1.050
1.100
1.200
1.500
1.800
EN
DAC Voltage
PGOOD
PG_OUT
EN
DAC VOLTAGE
NOTE: 1 = Input High, 0 = Input Low, FLOAT = Input unconnected or high-Z
(see “Electrical Specifications” table for details).
This allows the user to program the output voltage without the
use of a resistor divider network. However, if the user wishes to
program values of VOUT away from the DAC values, a resistor
divider can be used. However, because the input impedance of
the VOUT pin is relatively low, the top resistor in the divider stack
(R1 in Figure 31) must be kept small to minimize regulation error
as the internal resistance changes over-temperature and process
tolerances. A 100 Ω resistor is recommended. The bottom
2.5mV
VOUT
2.5mV
resistor in the divider stack (R2 in Figure 31) can be derived from
Equation 3:
1us
t SS
R1 ? V DAC
V OUT + ? --------------- ? – ? --------------------------- ? ? V DAC
1μs
t SS
R2 = -------------------------------------------------------------------------------------------------------
2 ? R1 205k + R 1
? 205k ? ? 205k ?
(EQ. 3)
V DAC
t SS = ------------------
FIGURE 25. IDEALIZED SOFT-START WAVEFORM
Using the values in Tables 1 and 2, the soft-start interval can be
easily calculated by Equation 1.
(EQ. 1)
0.0025
The units of Equation 1 are in microseconds. For example:
- VDAC = 1.200V
- t SS = 1.200V / 0.0025 = 480μs
The fixed soft-start slew rate of 2.5mV/μs allows for easy
calculation of the in-rush current.
For example:
- Desired VOUT = 1.35V
- VDAC = 1.32V (1.2V +10% margin)
- R1 = 100 Ω
- R2 = 4.351k Ω (select nearest standard value)
NOTE: The resistor divider should not be used to program VOUT
more than 5% away from any preset DAC value. If this limit is
exceeded, the modulator will be severely imbalanced and may
result in loop instability and regulator shutdown.
The use of a resistor network also limits the soft discharge
I INRUSH = ( 2500 ? C OUT )
(EQ. 2)
feature of the ISL95210. More detail on this operation can be
Consequently, the in-rush is manageable for all practical values
of output capacitance. For example:
- COUT = 330μF
- Inrush Current = 2500*330μF = 0.825A
11
In addition to digitally controlled output voltage programming,
the ISL95210 includes the ability to margin the output voltage up
and down from the set point for use in end-of-line manufacturing
reliability tests. The MPCT pin controls the amount of margining
desired by the user and the MSEL pin determines when
margining is engaged. In all margining conditions, the output
voltage is slewed to the new value at the soft-start rate of
FN6938.4
December 15, 2011
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相关代理商/技术参数
参数描述
ISL95210HRZ 功能描述:直流/直流开关调节器 ISL95210 5V/10ABUCK IGRATE FET NTBOOK RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
ISL95210HRZ-T 功能描述:直流/直流开关调节器 ISL95210 5V/10ABUCK IGRATE FET NTBOOK RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
ISL95210HRZ-T7A 功能描述:直流/直流开关调节器 ISL95210 5V/10ABUCK IGRATE FET NTBOOK RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
ISL95210IRZ 功能描述:直流/直流开关调节器 ISL95210 5V/10ABUCK IGRATE FET INDUST RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5
ISL95210IRZ-T 功能描述:直流/直流开关调节器 ISL95210 5V/10ABUCK IGRATE FET NTBOOK RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5