参数资料
型号: ISL6526ACR
厂商: Intersil
文件页数: 9/15页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM VM 16-QFN
标准包装: 60
PWM 型: 电压模式
输出数: 1
频率 - 最大: 645kHz
占空比: 100%
电源电压: 2.97 V ~ 3.63 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: 0°C ~ 70°C
封装/外壳: 16-VQFN 裸露焊盘
包装: 管件
ISL6526, ISL6526A
(such as to other distributed loads on the rail or through a
voltage limiting protection device), the capacitance on this
rail will absorb the current. This situation will allow the
voltage level of the input rail to increase. If the voltage level
of the rail is boosted to a level that exceeds the maximum
voltage rating of any components attached to the input rail,
then those components may experience an irreversible
failure or experience stress that may shorten their lifespan.
ISL6526, ISL6526A
VCC
CPVOUT
C VCC
+3.3V V IN
Ensuring that there is a path for the current to flow other than
the capacitance on the rail will prevent this failure mode.
GND
C BP
D1
C IN
Application Guidelines
BOOT
Layout Considerations
C BOOT
Q1
Layout is very important in high frequency switching
converter design. With power devices switching efficiently at
300kHz or 600kHz, the resulting current transitions from one
device to another cause voltage spikes across the
UGATE
PHASE
LGATE
PHASE
Q2
L OUT
C OUT
V OUT
interconnecting impedances and parasitic circuit elements.
These voltage spikes can degrade efficiency, radiate noise
into the circuit, and lead to device overvoltage stress.
COMP
C 2
Careful component layout and printed circuit board design
minimize the voltage spikes in the converters.
As an example, consider the turn-off transition of the PWM
FB
R 2
R4
C 1
R 1
C 3 R 3
MOSFET. Prior to turn-off, the MOSFET is carrying the full load
current. During turn-off, current stops flowing in the MOSFET
and is picked up by the lower MOSFET. Any parasitic
inductance in the switched current path generates a large
voltage spike during the switching interval. Careful component
selection, tight layout of the critical components, and short, wide
traces minimize the magnitude of voltage spikes.
There are two sets of critical components in a DC/DC
converter using the ISL6526, ISL6526A. The switching
components are the most critical because they switch large
amounts of energy, and therefore tend to generate large
amounts of noise. Next are the small signal components
which connect to sensitive nodes or supply critical bypass
current and signal coupling.
A multi-layer printed circuit board is recommended. Figure 4
shows the connections of the critical components in the
converter. Note that capacitors C IN and C OUT could each
represent numerous physical capacitors. Dedicate one solid
layer (usually a middle layer of the PC board) for a ground
plane and make all critical component ground connections
with vias to this layer. Dedicate another solid layer as a
power plane and break this plane into smaller islands of
common voltage levels. Keep the metal runs from the
PHASE terminals to the output inductor short. The power
plane should support the input power and output power
nodes. Use copper filled polygons on the top and bottom
circuit layers for the phase nodes. Use the remaining printed
circuit layers for small signal wiring. The wiring traces from
the GATE pins to the MOSFET gates should be kept short
and wide enough to easily handle the 1A of drive current.
9
KEY
ISLAND ON POWER PLANE LAYER
ISLAND ON CIRCUIT PLANE LAYER
VIA CONNECTION TO GROUND PLANE
FIGURE 4. PRINTED CIRCUIT BOARD POWER PLANES
AND ISLANDS
The switching components should be placed close to the
ISL6526, ISL6526A first. Minimize the length of the connections
between the input capacitors, C IN , and the power switches by
placing them nearby. Position both the ceramic and bulk input
capacitors as close to the upper MOSFET drain as possible.
Position the output inductor and output capacitors between the
upper MOSFET and lower MOSFET and the load.
The critical small signal components include any bypass
capacitors, feedback components, and compensation
components. Position the bypass capacitor, C BP , close to
the VCC pin with a via directly to the ground plane. Place the
PWM converter compensation components close to the FB
and COMP pins. The feedback resistors for both regulators
should also be located as close as possible to the relevant
FB pin with vias tied straight to the ground plane as required.
Feedback Compensation
Figure 5 highlights the voltage-mode control loop for a
synchronous-rectified buck converter. The output voltage
(V OUT ) is regulated to the Reference voltage level. The
error amplifier (Error Amp) output (V E/A ) is compared with
the oscillator (OSC) triangular wave to provide a pulse
width modulated (PWM) wave with an amplitude of V IN at
FN9055.10
November 24, 2008
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相关代理商/技术参数
参数描述
ISL6526ACR-T 功能描述:IC REG CTRLR BUCK PWM VM 16-QFN RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6526AEVAL1 功能描述:EVALUATION BOARD 1 ISL6526A RoHS:否 类别:编程器,开发系统 >> 评估板 - DC/DC 与 AC/DC(离线)SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC,步升 输出及类型:1,非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
ISL6526AEVAL2 功能描述:EVALUATION BOARD 2 ISL6526A RoHS:否 类别:编程器,开发系统 >> 评估板 - DC/DC 与 AC/DC(离线)SMPS 系列:- 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC,步升 输出及类型:1,非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969
ISL6526AIB 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR)
ISL6526AIB-T 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,000 系列:- PWM 型:电压模式 输出数:1 频率 - 最大:1.5MHz 占空比:66.7% 电源电压:4.75 V ~ 5.25 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:40-VFQFN 裸露焊盘 包装:带卷 (TR)