参数资料
| 型号： | ISL8560IRZ-T |
| 厂商： | Intersil |
| 文件页数： | 12/17页 |
| 文件大小： | 0K |
| 描述： | IC REG BUCK SYNC ADJ 2A 20QFN |
| 标准包装： | 4,000 |
| 类型： | 降压（降压） |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 1.21 V ~ 55 V |
| 输入电压： | 9 V ~ 60 V |
| PWM 型： | 电压模式 |
| 频率 - 开关： | 100kHz ~ 600kHz |
| 电流 - 输出： | 2A |
| 同步整流器： | 是 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 20-VQFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 20-QFN（6x6） |
ISL8560
Fault Protection
The ISL8560 monitors the output of the regulator for
overcurrent and undervoltage events. The ISL8560 also
provides protection from excessive junction temperatures.
Overcurrent Protection
The overcurrent function protects the switching converter from
a shorted output by monitoring the current flowing through the
upper MOSFETs.
Upon detection of overcurrent condition, the upper MOSFET
will be immediately turned off and will not be turned on again
until the next switching cycle. Upon detection of the initial
overcurrent condition, the overcurrent fault counter is set to
1 and the overcurrent condition flag is set from LOW to
HIGH. If, on the subsequent cycle, another overcurrent
condition is detected, the OC fault counter will be
incremented. If there are seven sequential OC fault
detections, the regulator will be shut down under an
overcurrent fault condition. An overcurrent fault condition will
result with the regulator attempting to restart in a hiccup
mode with the delay between restarts being 4 soft-start
periods. At the end of the fourth soft-start wait period, the
fault counters are reset and soft-start is attempted again. If
the overcurrent condition goes away prior to the OC fault
counter reaching a count of four, the overcurrent condition
flag will set back to LOW.
If the overcurrent condition flag is HIGH and the overcurrent
fault counter is less than four and an undervoltage event is
detected, the regulator will be shut down immediately.
Undervoltage Protection
If the voltage detected on the FB pin falls 14% below the
internal reference voltage and the overcurrent condition flag
is LOW, then the regulator will be shut down immediately
under an undervoltage fault condition. An undervoltage fault
condition will result with the regulator attempting to restart in
a hiccup mode with the delay between restarts being 4
High frequency capacitors initially supply the transient and
slow the current load rate seen by the bulk capacitors. The
bulk filter capacitor values are generally determined by the
ESR (Effective Series Resistance) and voltage rating
requirements rather than actual capacitance requirements.
High frequency decoupling capacitors should be placed as
close to the power pins of the load as physically possible. Be
careful not to add inductance in the circuit board wiring that
could cancel the usefulness of these low inductance
components. Consult with the manufacturer of the load on
specific decoupling requirements.
The shape of the output voltage waveform during a load
transient that represents the worst case loading conditions
will ultimately determine the number of output capacitors and
their type. When this load transient is applied to the
converter, most of the energy required by the load is initially
delivered from the output capacitors. This is due to the finite
amount of time required for the inductor current to slew up to
the level of the output current required by the load. This
phenomenon results in a temporary dip in the output voltage.
At the very edge of the transient, the Equivalent Series
Inductance (ESL) of each capacitor induces a spike that
adds on top of the existing voltage drop due to the
Equivalent Series Resistance (ESR).
After the initial spike, attributable to the ESR and ESL of the
capacitors, the output voltage experiences sag. This sag is a
direct consequence of the amount of capacitance on the output.
During the removal of the same output load, the energy
stored in the inductor is dumped into the output capacitors.
This energy dumping creates a temporary hump in the
output voltage. This hump, as with the sag, can be attributed
to the total amount of capacitance on the output. Figure 29
shows a typical response to a load transient.
soft-start periods. At the end of the fourth soft-start wait
period, the fault counters are reset and soft-start is
attempted again.
Thermal Protection
If the ISL8560 IC junction temperature reaches a nominal
temperature of +150°C, the regulator will be disabled. The
ISL8560 will not re-enable the regulator until the junction
temperature drops below +135°C.
Output Capacitor Selection
V OUT
Δ V HUMP
Δ V ESR
Δ V SAG
Δ V ESL
An output capacitor is required to filter the inductor current
and supply the load transient current. The filtering
requirements are a function of the switching frequency and
the ripple current. The load transient requirements are a
function of the slew rate (di/dt) and the magnitude of the
transient load current. These requirements are generally met
I OUT
I tran
with a mix of capacitors and careful layout.
12
FIGURE 29. TYPICAL TRANSIENT RESPONSE
FN9244.7
September 19, 2008
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相关代理商/技术参数 |
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|---|---|
| ISL8560MREP | 制造商:Intersil Corporation 功能描述:V62/08608-01XB, -55 TO 125C VID VERSION OF THE ISL8560, 20LD - Rail/Tube |
| ISL8560M-REP | 制造商:Intersil Corporation 功能描述:CONV DC-DC SGL-OUT STEP DOWN 20QFN EP - Rail/Tube |
| ISL8560MREP-TK | 制造商:Intersil Corporation 功能描述:CONV DC-DC SGL-OUT STEP DOWN 20QFN EP - Tape and Reel |
| ISL8563 WAF | 制造商:Intersil Corporation 功能描述: |
| ISL8563CB | 制造商:Rochester Electronics LLC 功能描述:RS562 3V 2D/2R SHUTDOWN 18SOIC COM - Bulk |
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