参数资料
| 型号： | ISL6539IA |
| 厂商： | Intersil |
| 文件页数： | 9/20页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR DDR DRAM, SDRAM 28QSOP |
| 标准包装： | 48 |
| 应用： | 控制器，DDR DRAM，SDRAM |
| 输入电压： | 3.3 V ~ 18 V |
| 输出数： | 2 |
| 输出电压： | 0.9 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-SSOP（0.154"，3.90mm 宽） |
| 供应商设备封装： | 28-SSOP/QSOP |
| 包装： | 管件 |
ISL6539
Theory of Operation
Operation
The ISL6539 is a dual channel PWM controller intended for
use in power supplies for graphic chipsets, SDRAM, DDR
1
EN
DRAM, or other power applications. The IC integrates two
control circuits for two synchronous buck converters. The
output voltage of each controller can be set in the range of
2
0.9V
1.5V
SOFT
0.9V to 5.5V by an external resistive divider.
The synchronous buck converters can operate from either
3
VOUT
an unregulated DC source with a voltage ranging from 5.0V
to 15V, or from a regulated system rail of 3.3V or 5V. In either
operational mode the controller is biased from the +5V
4
PGOO D
source.
Ch1 5.0V
Ch2 2.0V
M1.00ms
The controllers operate in the current mode with input
voltage feed-forward which simplifies feedback loop
compensation and rejects input voltage variation. An
integrated feedback loop compensation dramatically
reduces the number of external components.
The ISL6539 has a special means to rearrange its internal
architecture into a complete DDR solution. When the DDR
pin is set high, the second channel can provide the capability
Ch3 1.0V Ch4 5.0V
FIGURE 5. START-UP
Even though the soft-start pin voltage continues to rise after
reaching 1.5V, this voltage does not affect the output
voltage.
The soft-start time (the time from the moment when EN
becomes high to the moment when PGOOD is reported) is
determined by Equation 1:
T S OFT = ----------------------------------
to track the output voltage of the first channel. The buffered
reference voltage required by DDR memory chips is also
1.5 V × C sof t
5 μ A
(EQ. 1)
provided.
The time it takes the output voltage to come into regulation
Initialization
The ISL6539 initializes if at least one of the enable pins is
can be obtained from Equation 2:
T R ISE = 0.6 × T SOFT
(EQ. 2)
V O = ----------------------------------------------
set high. The Power-On Reset (POR) function continually
monitors the bias supply voltage on the VCC pin, and
initiates soft-start operation when EN1 or EN2 is high after
the input supply voltage exceeds 4.45V. Should this voltage
drop lower than 4.14V, the POR disables the chip.
Soft-Start
When soft-start is initiated, the voltage on the SOFT pin of
the enabled channel starts to ramp up gradually with the
internal 5μA current charging the soft-start capacitor. The
output voltage follows the soft-start voltage.
When the SOFT pin voltage reaches 0.9V, the output voltage
comes into regulation. When the SOFT voltage reaches
1.5V, the power good (PGOOD) is enabled. The soft-start
process is depicted in Figure 5.
9
During soft-start, before the PGOOD pin is enabled, the
undervoltage protection is prohibited. The overvoltage and
overcurrent protection functions are enabled.
If the output capacitor has residue voltage before start-up,
both lower and upper MOSFETs are in off-state until the
soft-start capacitor charges equal the VSEN pin voltage.
This will ensure the output voltage starts from its existing
voltage level.
Output Voltage Program
The output voltage of either channel is set by a resistive
divider from the output to ground. The center point of the
divider is connected to the VSEN pin as shown in Figure 6.
The output voltage value is determined by Equation 3.
0.9 V ? ( R1 + R 2 ) (EQ. 3)
R2
where 0.9V is the value of the internal reference. The VSEN
pin voltage is also used by the controller for the power good
function and to detect undervoltage and overvoltage
conditions.
FN9144.6
April 29, 2010
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL6539IA-T | 功能描述:IC CTRLR DDR DRAM, SDRAM 28QSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,000 系列:- 应用:电源，ICERA E400，E450 输入电压:4.1 V ~ 5.5 V 输出数:10 输出电压:可编程 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:42-WFBGA，WLCSP 供应商设备封装:42-WLP 包装:带卷 (TR) |
| ISL6539IAZ | 功能描述:电流型 PWM 控制器 ISL6539 DL SWITCHER 15V INDUSTRIAL GRD 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 |
| ISL6539IAZ-T | 功能描述:电流型 PWM 控制器 ISL6539 DL SWITCHER 15V INDUSTRIAL GRD 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 |
| ISL6540ACRZ | 功能描述:IC REG CTRLR BUCK PWM VM 28-QFN 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:75 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.3 V ~ 13.5 V 降压:是 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:0°C ~ 70°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:管件 产品目录页面:1051 (CN2011-ZH PDF) 其它名称:296-2543-5 |
| ISL6540ACRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 28-QFN 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 |
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