参数资料
型号: ISL9111EHADJZ-T7A
厂商: Intersil
文件页数: 9/15页
文件大小: 0K
描述: IC REG BST SYNC ADJ 1A 6SOT23-6
标准包装: 1
类型: 升压(升压)
输出类型: 可调式
输出数: 1
输出电压: 2.5 V ~ 5.25 V
输入电压: 0.8 V ~ 5.05 V
PWM 型: 电流模式
频率 - 开关: 1.2MHz
电流 - 输出: 1A
同步整流器:
工作温度: -20°C ~ 85°C
安装类型: 表面贴装
封装/外壳: SOT-23-6
包装: 标准包装
供应商设备封装: SOT-23-6
其它名称: ISL9111EHADJZ-T7ADKR
ISL9111, ISL9111A
2. UVLO function is disabled in the ISL9111A. The minimum
start-up voltage can be as low as 0.6V, and minimum
operating voltage can be as low as 0.5V after start-up. The
advantage of minimum operating voltage maximizes the
performance of a non-rechargeable battery, allowing the
system to operate until the battery is fully depleted.
Soft-start
When the device is enabled, the start-up cycle starts with linear
phase. During linear phase, the rectifying switch is turned on in a
current limited configuration, delivering about 200mA, until the
output capacitor is charged to approximately 90% of the input
voltage. At this point, PWM begins, and thus, boost operation
starts. If the output voltage is below 2.3V, PWM switching is done
at a fixed duty-cycle of 75% until the output voltage reaches 2.3V.
When the output voltage exceeds 2.3V, the closed-loop current
mode PWM loop overrides the duty cycle until the output voltage
is regulated. Peak inductor current is ramped to the final value
(typically 1A) during the soft-start period to limit in-rush current
from the input source. Fault monitoring begins approximately
2ms after the device is enabled.
Over-temperature Protection (OTP)
The device offers over-temperature protection. A temperature
sensor circuit is integrated and monitors the internal IC
temperature. Once the temperature exceeds the preset threshold
(typically +150°C), the IC shuts down immediately. The OTP has
a typical hysteresis of +25°C. When the device temperature
decreases by this, the device starts operating.
Overvoltage Protection (OVP)
The adjustable version of the ISL9111 and ISL9111A have built
in overvoltage protection (OVP) to enhance product robustness
for transient up to 8V on SW pin. V OUT is actively monitored, and
should the voltage reach 5.9V (typical), the device will stop
switching. This turns off both power MOSFETs and the stored
inductor energy is discharged to V OUT through the body diode of
the synchronous rectifier.
Fault Monitoring and Reporting
Fault monitoring starts 2ms after start-up. Table 1 shows the
response to different detected faults. Any fault condition shown
in Table 1 causes the FAULT pin to be taken low. The FAULT pin
will not release until V IN and V OUT fully collapse or until the fault
condition is removed.
Board Layout Recommendations
carry high switching current should be routed wide and short. A
solid power ground plane is important for EMI suppression.
The switching node (SW pin) of the converter and the traces
connected to this pin are noisy. Noise sensitive traces such as the
feedback trace should be kept away from SW pin and traces. The
voltage divider should be placed close to the feedback pin to
prevent noise pickup. Figure 6 shows the recommended EVB
layout.
V IN GND
V OUT
GND
FIGURE 6. RECOMMENDED EVALUATION BOARD LAYOUT
Fixed Output Voltage and Adjustable Output
Voltage
ISL9111 and ISL9111A offer options for fixed output voltages of
5V, 3.3V and 3V, or an adjustable output voltage.
For fixed output voltage versions (ISL9111-5.0, ISL9111A-5.0,
ISL9111-3.3, ISL9111A-3.3, ISL9111-3.0, ISL9111A-3.0), an
internal voltage divider is used (see “Block Diagram: ISL9111-
adjustable output voltage version (ISL9111-ADJ, ISL9111A -ADJ),
the output voltage is programmed by connecting two external
voltage divider resistors among OUT, FB and GND (see “Block
Output Voltage Setting Resistor Selection
For the ISL9111 adjustable output version, the resistors, R 1 and
R 2 , as shown in the block diagram on page 2, set the desired
output voltage values. The output voltage can be calculated using
V O = V FB ? ? 1 + ------- ?
The ISL9111 and ISL9111A are high frequency switching boost
converters. Accordingly, the converter creates fast voltage
changes and high switching current that may cause EMI and
stability issues if good PCB layout practices are not followed.
Although the ISL9111 and ISL9111A can tolerate short durations
Equation 1:
? R 1 ?
? R 2 ?
where V FB is the internal feedback reference voltage (0.8V
typical). The current flowing through the divider resistors is
(EQ. 1)
of 8.0V transients, prolonged or higher amplitude excursions may
damage the device. Care should be taken to minimize the trace
inductance and reduce the area of the power loop.
Power components such as input capacitor, inductor and output
capacitor should be placed close to the device. Board traces that
9
calculated as V O /(R 1 + R 2 ). Large resistance is recommended to
minimize current into the divider and thus improve the total
efficiency of the converter. R 1 and R 2 should be placed close to
the feedback pin of the device to prevent noise pickup.
FN7602.4
June 4, 2012
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