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参数资料
| 型号： | ISL8105BCRZ-T |
| 厂商： | Intersil |
| 文件页数： | 14/16页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM VM 10-DFN |
| 标准包装： | 6,000 |
| PWM 型： | 电压模式 |
| 输出数： | 1 |
| 频率 - 最大： | 330kHz |
| 占空比： | 100% |
| 电源电压： | 6.5 V ~ 14.4 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： | 10-VFDFN 裸露焊盘 |
| 包装： | 带卷 (TR) |
ISL8105B
heatsink may be necessary depending upon MOSFET
power, package type, ambient temperature and air flow.
+V BIAS
+1V TO +12V
P TOP = Io × r DS ( ON ) × D + --- ? Io × V IN × t SW × F S
V D
Losses while Sourcing Current
2 1
2
P BOTTOM = Io 2 x r DS(ON) x (1 - D)
ISL8105B
+
-
BOOT
TGATE
C BOOT
Q 1
V G-S ≈ V BIAS - V D
Losses while Sinking Current
P TOP = Io 2 x r DS(ON) x D
LX
P BOTTOM = Io × r DS ( ON ) × ( 1 – D ) + --- ? Io × V IN × t SW × F S
2 1
2
(EQ. 14)
-
+
+V BIAS
BGATE
Q 2
NOTE:
V G-S ≈ V BIAS
Where:
D is the duty cycle = V OUT / V IN ,
t SW is the combined switch ON and OFF time, and
f S is the switching frequency.
When operating with a 12V power supply for V BIAS (or down
to a minimum supply voltage of 6.5V), a wide variety of
N-Channel MOSFETs can be used. Check the absolute
maximum V GS rating for both MOSFETs; it needs to be
above the highest V BIAS voltage allowed in the system; that
usually means a 20V V GS rating (which typically correlates
with a 30V V DS maximum rating). Low threshold transistors
(around 1V or below) are not recommended for the reasons
explained in the next paragraph.
For 5V-only operation, given the reduced available gate bias
voltage (5V), logic-level transistors should be used for both
N-MOSFETs. Look for r DS(ON) ratings at 4.5V. Caution
should be exercised with devices exhibiting very low
V GS(ON) characteristics. The shoot-through protection
present aboard the ISL8105 may be circumvented by these
MOSFETs if they have large parasitic impedances and/or
capacitances that would inhibit the gate of the MOSFET from
being discharged below its threshold level before the
complementary MOSFET is turned on. Also avoid MOSFETs
with excessive switching times; the circuitry is expecting
transitions to occur in under 50ns or so.
Bootstrap Considerations
Figure 12 shows the top-side gate drive (BOOT pin) supplied
by a bootstrap circuit from V BIAS . The boot capacitor,
C BOOT , develops a floating supply voltage referenced to the
LX pin. The supply is refreshed to a voltage of V BIAS less
the boot diode drop (V D ) each time the lower MOSFET, Q 2 ,
14
GND
FIGURE 12. UPPER GATE DRIVE - BOOTSTRAP OPTION
turns on. Check that the voltage rating of the capacitor is
above the maximum V BIAS voltage in the system. A 16V
rating should be sufficient for a 12V system. A value of 0.1μF
is typical for many systems driving single MOSFETs.
If V BIAS is 12V, but V IN is lower (such as 5V), then another
option is to connect the BOOT pin to 12V and remove the
BOOT cap (although, you may want to add a local cap from
BOOT to GND). This will make the TGATE V GS voltage
equal to (12V - 5V = 7V). That should be high enough to
drive most MOSFETs, and low enough to improve the
efficiency slightly. Do NOT leave the BOOT pin open, and try
to get the same effect by driving BOOT through V BIAS and
the internal diode; this path is not designed for the high
current pulses that will result.
For low V BIAS voltage applications where efficiency is very
important, an external BOOT diode (in parallel with the
internal one) may be considered. The external diode drop
has to be lower than the internal one. The resulting higher
V G-S of the top-side FET will lower its r DS(ON) . The modest
gain in efficiency should be balanced against the extra cost
and area of the external diode.
For information on the Application circuit, including a
complete Bill-of-Materials and circuit board description, can
be found in Application Note AN1288.
FN6447.2
April 15, 2010
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相关代理商/技术参数 |
参数描述 |
|---|---|
| ISL8105BEVAL1Z | 功能描述:EVAL BOARD ISL8105B RoHS:是 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 |
| ISL8105BEVAL2Z | 功能描述:EVALUATION BOARD FOR ISL8105B RoHS:是 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 |
| ISL8105BIBZ | 功能描述:IC REG CTRLR BUCK PWM VM 8-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) |
| ISL8105BIBZ-T | 功能描述:IC REG CTRLR BUCK PWM VM 8-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) |
| ISL8105BIRZ | 功能描述:IC REG CTRLR BUCK PWM VM 10-DFN 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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