参数资料
| 型号： | EL7571CM |
| 厂商： | Intersil |
| 文件页数： | 8/19页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR PWM PROGRAMMABLE 20SOIC |
| 标准包装： | 38 |
| 应用： | 控制器，Intel Pentium? II，Pro |
| 输入电压： | 4.5 V ~ 12.6 V |
| 输出数： | 2 |
| 输出电压： | 1.3 V ~ 3.5 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-SOIC（0.295"，7.50mm 宽） |
| 供应商设备封装： | 20-SO |
| 包装： | 管件 |
EL7571
Modern logic level power FET’s rapidly increase in resistivity
(R DS-ON ) as their gate drive is reduced below 5V. To prevent
thermal damage to the power FET’s under load, with a
reduced supply voltage, the system watchdog monitors the
controller supply (V IN ) and disables both PWM outputs
(HSD, LSD) when the supply voltage drops below 3.5V.
When the supply voltage is increased above 4V the
watchdog initiates a soft-start ramp and enables PWM
operation. The difference between enable and disable
thresholds introduces hysteresis into the circuit operation,
preventing start-up oscillation. In addition, output voltage is
also monitored by the watchdog. As called out by the Intel
Pentium? II VRM specification, the watchdog power good
output (PWRGD) is set low whenever the output voltage
differs from it’s selected value by more than ±13%. PWRGD
is an open drain output. A third watchdog function disables
PWM output switching during over-voltage fault conditions,
displaying both external FET drives, whenever the output
voltage is greater than 13% of its selected value, thereby
anticipating reverse inductor current ramping and
conforming to the VRM over-voltage specification, which
requires the regulator output to be disabled during fault
conditions. Switching is enabled after the fault condition is
removed.
Output Drivers
Complementary control signals developed by the PWM
level shift circuit. Each driver is capable of delivering nominal
peak output currents of 2A at 12V. To prevent shoot-through
in the external FET’s, each driver is disabled until the gate
voltage of the complementary power FET has fallen to less
than 1V. Supply connections for both drivers are
independent, allowing the controller to be configured with a
boot-strapped high side drive. Employing this technique a
single supply voltage may be used for both power FET’s and
controller. Alternatively, the application may be simplified
using dual supply rails with the power FET’s connected to a
secondary supply voltage below the controller’s, typically
12V and 5V. For applications where efficiency is less
important than cost, applications can be further simplified by
replacing the low side power FET with a Schottky diode,
resulting in non-synchronous operation.
Applications Information
The EL7571 is designed to meet the Intel 5 bit VRM
specification. Refer to the VID decode table for the controller
output voltage range.
The EL7571 may be used in a number converter topologies.
The trade-off between efficiency, cost, circuit complexity, line
input noise, transient response and availability of input
supply voltages will determine which converter topology is
suitable for a given application. The following table lists some
of the differences between the various configurations:
control loop are fed to dual NMOS power FET drivers via a
Converter Topologies
TRANSIENT
TOPOLOGY
DIAGRAM
EFFICIENCY
COST
COMPLEXITY INPUT NOISE
RESPONSE
5V only Non-synchronous
5V only Synchronous
5V &12V Non-synchronous
5V & 12V Synchronous
12V only Synchronous
figure 1
figure 2
figure 3
figure 4
Connection Diagram
92%
95%
92%
95%
92%
low
higher
lowest
high
highest
low
higher
lowest
high
highest
high
high
high
high
high
good
good
good
good
best
V IN × F SW × 2 × I MIN
1 PEAK
Circuit schematics and Bills of Material (BOMs) for the
various topologies are provided at the end of this data sheet.
If your application requirements differ from the included
samples, the following design guide lines should be used to
select the key component values. Refer to the front page
connection diagram for component locations.
Output Inductor, L 1
Two key converter requirements are used to determine
inductor value:
? I MIN - minimum output current; the current level at which
the converter enters the discontinuous mode of operation
(refer to Elantec application note #18 for a detailed
discussion of discontinuous mode)
? I MAX - maximum output current
8
Although many factors influence the choice of the inductor
value, including efficiency, transient response and ripple
current, one practical way of sizing the inductor is to select a
value which maintains continuous mode operation, i.e.
inductor current positive for all conditions. This is desirable to
optimize load regulation and light load transient response.
When the minimum inductor ripple current just reaches zero
and with the mean ripple current set to I MIN , peak inductor
ripple current is twice I MAX , independent of duty cycle. The
minimum inductor value is given by:
( V IN – V OUT ) × T ON ( V IN – V OUT ) × V OUT
L 1MIN = -------------------------------------------------------- = ------------------------------------------------------------
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| EL7571CM-T13 | 功能描述:IC CTRLR PWM PROGRAMMABLE 20SOIC 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) |
| EL7571CMZ | 功能描述:IC CTRLR PWM PROGRAMMABLE 20SOIC RoHS:是 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) |
| EL7571CMZ-T13 | 功能描述:IC CTRLR PWM PROGRAMMABLE 20SOIC RoHS:是 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) |
| EL7581 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:3-Channel DC-DC Converter |
| EL7581_06 | 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:3-Channel DC/DC Converter |
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