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| 型号： | LTC3813EG#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 20/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BST PWM CM 28-SSOP |
| 标准包装： | 2,000 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1MHz |
| 电源电压： | 7 V ~ 75 V |
| 降压： | 无 |
| 升压： | 是 |
| 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： | 28-SSOP（0.209"，5.30mm 宽） |
| 包装： | 带卷 (TR) |
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LTC3813
APPLICATIONS INFORMATION
Input Voltage Undervoltage Lockout
A resistor divider connected from the input supply to the
UVIN pin (see Functional Diagram) is used to program the
input supply undervoltage lockout thresholds. When the
rising voltage at UVIN reaches 0.88V, the LTC3813 turns
on, and when the falling voltage at UVIN drops below 0.8V,
the LTC3813 is shut down —providing 10% hysteresis.
The input voltage UVLO thresholds are set by the resistor
divider according to the following formulas:
BGRTN to ground? In high voltage switching converters,
the switch node dV/dt can be many volts/ns, which will
pull up on the gate of the bottom MOSFET through its
Miller capacitance. If this Miller current, times the internal
gate resistance of the MOSFET plus the driver resistance,
exceeds the threshold of the FET, shoot-through will oc-
cur. By using a negative supply on BGRTN, the BG can be
pulled below ground when turning the bottom MOSFET off.
This provides a few extra volts of margin before the gate
reaches the turn-on threshold of the MOSFET. Be aware
V IN,FALLING = 0.8V ? 1 +
and
R UV1
R UV2
that the maximum voltage difference between DRV CC and
BGRTN is 14V. If, for example, V BGRTN = –2V, the maximum
voltage on DRV CC pin is now 12V instead of 14V.
V IN,RISING = 0.88V ? 1 + UV1
R
R UV2
If input supply undervoltage lockout is not needed, it can
be disabled by connecting UVIN to INTV CC .
Top MOSFET Driver Supply (C B , D B )
An external bootstrap capacitor C B connected to the BOOST
pin supplies the gate drive voltage for the topside MOSFET.
This capacitor is charged through diode D B from DRV CC
when the switch node is low. When the top MOSFET turns
on, the switch node rises to V OUT and the BOOST pin
rises to approximately V OUT + DRV CC . The boost capacitor
needs to store about 100x the gate charge required by the
top MOSFET. In most applications, 0.1μF to 0.47μF, X5R
or X7R dielectric capacitor is adequate.
The reverse breakdown of the external diode, D B , must be
greater than V OUT . Another important consideration for the
external diode is the reverse recovery and reverse leakage,
either of which may cause excessive reverse current to ?ow
at full reverse voltage. If the reverse current times reverse
voltage exceeds the maximum allowable power dissipa-
tion, the diode may be damaged. For best results, use an
ultrafast recovery diode such as the MMDL770T1.
Bottom MOSFET Driver Return Supply (BGRTN)
The bottom gate driver, BG, switches from DRV CC to
BGRTN where BGRTN can be a voltage between ground
IC/MOSFET Driver Supplies (INTV CC and DRV CC )
The LTC3813 drivers are supplied from the DRV CC pin
and the LTC3813 internal circuits from INTV CC pin (see
Figure 1). These pins have an operating range between
6.2V and 14V. If the input voltage or another supply is not
available in this voltage range, two internal regulators are
provided to simplify the generation of this IC/driver supply
voltage as described in the next sections.
The N DRV Pin Regulator
The N DRV pin controls the gate of an external NMOS as
shown in Figure 9b and can be used to generate a regu-
lated 10V supply from V IN or V OUT . Since the NMOS is
external, it can be chosen with a BV DSS or power rating
as high as necessary to safely derive power from a high
voltage input or output voltage. In order to generate an
INTV CC supply that is always above the 6.2V UV threshold,
the supply connected to the drain must be greater than
6.2V + R NDRV ? 40μA + V T .
The EXTV CC Pin Regulator
A second low dropout regulator is available for voltages
≤ 15V. When a supply that is greater than 6.7V is con-
nected to the EXTV CC pin, the internal LDO will regulate
10V on INTV CC from the EXTV CC pin voltage and will also
disable the NDRV pin regulator. This regulator is disabled
when the IC is shut down, when INTV CC < 6.2V, or when
EXTV CC < 6.7V.
and –5V. Why not just keep it simple and always connect
3813fb
20
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相关代理商/技术参数 |
参数描述 |
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| LTC3813IG#PBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3813IG#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 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 ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX |
| LTC3814EFE-5#PBF | 功能描述:IC REG CTRLR BST PWM CM 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 特色产品:LM3753/54 Scalable 2-Phase Synchronous Buck Controllers 标准包装:1 系列:PowerWise® PWM 型:电压模式 输出数:1 频率 - 最大:1MHz 占空比:81% 电源电压:4.5 V ~ 18 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:-5°C ~ 125°C 封装/外壳:32-WFQFN 裸露焊盘 包装:Digi-Reel® 产品目录页面:1303 (CN2011-ZH PDF) 其它名称:LM3754SQDKR |
| LTC3814EFE-5#TRPBF | 功能描述:IC REG CTRLR BST PWM CM 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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 ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
| LTC3814IFE-5#PBF | 功能描述:IC REG CTRLR BST PWM CM 16-TSSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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 ~ 125°C 封装/外壳:24-WQFN 裸露焊盘 包装:带卷 (TR) |
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