参数资料
| 型号： | ISL6535CRZ |
| 厂商： | Intersil |
| 文件页数： | 7/14页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 16QFN |
| 标准包装： | 75 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.5MHz |
| 占空比： | 100% |
| 电源电压： | 10.8 V ~ 13.2 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： | 0°C ~ 70°C |
| 封装/外壳： | 16-VQFN 裸露焊盘 |
| 包装： | 管件 |
ISL6535
therefore, dependent upon the value of the soft-start
capacitor, C SS . If the internal reference is used, then the
soft-start capacitance value can be calculated through
Equation 3:
Overcurrent Protection
V SSDONE
C SS = ----------------------------
30 μ A ? t SS
2V
If an external reference is used, then the soft start
capacitance can be calculated through Equation 4:
(EQ. 3)
V SS
C SS = ----------------------------
30 μ A ? t SS
V REFEXT
(EQ. 4)
I OCP
V EN
I LOAD
V OUT
t HICCUP
FIGURE 4. TYPICAL OVERCURRENT PROTECTION
V SS
t SS
FIGURE 3. TYPICAL SOFT-START INTERVAL
Prebiased Load Startup
Drivers are held in tri-state (UG pulled to Phase, LG pulled to
PGND) at the beginning of a soft-start cycle until two PWM
pulses are detected. The low side MOSFET is turned on first
to provide for charging of the bootstrap capacitor. This method
of driver activation provides support for start-up into prebiased
loads by not activating the drivers until the control loop has
entered its linear region, thereby substantially reducing output
transients that would otherwise occur had the drivers been
activated at the beginning of the soft-start cycle.
SSDONE
Soft-start done is only available in the 16 Ld QFN packaging
option of the ISL6535. When the soft-start pin reaches 4V, an
open drain signal is provided to support sequencing
requirements. SSDONE is deasserted by disabling of the part,
including pulling SS low, and by POR and OCP events.
Oscillator
The oscillator is a triangular waveform, providing for leading
and falling edge modulation. The peak to peak of the ramp
amplitude is set at 1.9V and varies as a function of
frequency. At 50kHz the peak to peak amplitude is
approximately 1.8V while at 1.5MHz it is approximately 2.2V.
In the event the regulator operates at 100% duty cycle for 64
The OCP function is enabled with the drivers at start-up.
OCP is implemented via a resistor (R OCSET ) and a
capacitor (C OCSET ) connecting the OCSET pin and the
drain of the high side MOSEFT. An internal 200 μ A current
source develops a voltage across R OCSET , which is then
compared with the voltage developed across the high side
MOSFET at turn-on as measured at the PHASE pin. When
the voltage drop across the MOSFET exceeds the voltage
drop across the resistor, a sourcing OCP event occurs.
C OCSET is placed in parallel with R OCSET to smooth the
voltage across R OCSET in the presence of switching noise
on the input bus.
A 120ns blanking period is used to reduce the current
sampling error due to leading-edge switching noise. An
additional simultaneous 120ns low pass filter is used to
further reduce measurement error due to noise.
OCP faults cause the regulator to disable (upper and lower
drives disabled, SSDONE pulled low, soft-start capacitor
discharged) itself for a fixed period of time, after which a
normal soft-start sequence is initiated. If the voltage on the
SS pin is already at 4V and an OCP is detected, a 30mA
current sink is immediately applied to the SS pin. If an OCP
is detected during soft-start, the 30 μ A current sink will not be
applied until the voltage on the SS pin has reached 4V. This
current sink discharges the C SS capacitor in a linear fashion.
Once the voltage on the SS pin has reached approximately
0V, the normal soft-start sequence is initiated. If the fault is
still present on the subsequent restart, the ISL6535 will
repeat this process in a hiccup mode. Figure 4 shows a
typical reaction to a repeated overcurrent condition that
places the regulator in a hiccup mode. If the regulator is
repeatedly tripping overcurrent, the hiccup period can be
approximated by Equation 5:
t HICCUP = ------------------------
clock cycles an automatic boot cap refresh circuit will
activate turning on LG for approximately 1/2 of a clock cycle.
7
8V ? C SS
30 μ A
(EQ. 5)
FN9255.1
May 5, 2008
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| ISL6535CRZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 16-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
| ISL6535IBZ | 功能描述:IC REG CTRLR BUCK PWM VM 14-SOIC RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
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| ISL6535IRZ | 功能描述:IC REG CTRLR BUCK PWM VM 16QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:275kHz 占空比:50% 电源电压:18 V ~ 110 V 降压:无 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:是 工作温度:-40°C ~ 85°C 封装/外壳:8-SOIC（0.154"，3.90mm 宽） 包装:带卷 (TR) |
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