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参数资料
| 型号： | LTC3727EG-1 |
| 厂商： | Linear Technology |
| 文件页数： | 17/32页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 28-SSOP |
| 标准包装： | 47 |
| 系列： | PolyPhase® |
| PWM 型： | 电流模式 |
| 输出数： | 2 |
| 频率 - 最大： | 580kHz |
| 占空比： | 99% |
| 电源电压： | 4 V ~ 36 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 ~ 85°C |
| 封装/外壳： | 28-SSOP（0.209"，5.30mm 宽） |
| 包装： | 管件 |
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LTC3727/LTC3727-1
APPLICATIO S I FOR ATIO
INTV CC Regulator
An internal P-channel low dropout regulator produces
7.5V at the INTV CC pin from the V IN supply pin. INTV CC
powers the drivers and internal circuitry within the
LTC3727. The INTV CC pin regulator can supply a peak
current of 50mA and must be bypassed to ground with a
minimum of 4.7 μ F tantalum, 10 μ F special polymer, or low
ESR type electrolytic capacitor. A 1 μ F ceramic capacitor
placed directly adjacent to the INTV CC and PGND IC pins
is highly recommended. Good bypassing is necessary to
supply the high transient currents required by the MOSFET
gate drivers and to prevent interaction between channels.
Higher input voltage applications in which large MOSFETs
are being driven at high frequencies may cause the maxi-
mum junction temperature rating for the LTC3727 to be
exceeded. The system supply current is normally domi-
nated by the gate charge current. Additional external
loading of the INTV CC and 3.3V linear regulators also
needs to be taken into account for the power dissipation
calculations. The total INTV CC current can be supplied by
either the 7.5V internal linear regulator or by the EXTV CC
input pin. When the voltage applied to the EXTV CC pin is
less than 7.3V, all of the INTV CC current is supplied by the
internal 7.5V linear regulator. Power dissipation for the IC
in this case is highest: (V IN )(I INTVCC ), and overall efficiency
is lowered. The gate charge current is dependent on
operating frequency as discussed in the Efficiency Consid-
erations section. The junction temperature can be esti-
mated by using the equations given in Note 2 of the
Electrical Characteristics. For example, the LTC3727 V IN
current is limited to less than 24mA from a 24V supply
when not using the EXTV CC pin as follows:
T J = 70 ° C + (24mA)(24V)(95 ° C/W) = 125 ° C
Use of the EXTV CC input pin reduces the junction tempera-
ture to:
T J = 70 ° C + (24mA)(7.5V)(95 ° C/W) = 87 ° C
Dissipation should be calculated to also include any added
current drawn from the internal 3.3V linear regulator. To
prevent maximum junction temperature from being ex-
ceeded, the input supply current must be checked operat-
ing in continuous mode at maximum V IN .
EXTV CC Connection
The LTC3727 contains an internal P-channel MOSFET
switch connected between the EXTV CC and INTV CC pins.
When the voltage applied to EXTV CC rises above 7.3V, the
internal regulator is turned off and the switch closes,
connecting the EXTV CC pin to the INTV CC pin thereby
supplying internal power. The switch remains closed as
long as the voltage applied to EXTV CC remains above 7.0V.
This allows the MOSFET driver and control power to be
derived from the output during normal operation (7.2V <
V OUT < 8.5V) and from the internal regulator when the
output is out of regulation (start-up, short-circuit). If more
current is required through the EXTV CC switch than is
specified, an external Schottky diode can be added be-
tween the EXTV CC and INTV CC pins. Do not apply greater
than 8.5V to the EXTV CC pin and ensure that EXTV CC < V IN .
Significant efficiency gains can be realized by powering
INTV CC from the output, since the V IN current resulting
from the driver and control currents will be scaled by a
factor of (Duty Cycle)/(Efficiency). For 7.5V regulators this
supply means connecting the EXTV CC pin directly to V OUT .
However, for 3.3V and other lower voltage regulators,
additional circuitry is required to derive INTV CC power
from the output.
The following list summarizes the four possible connec-
tions for EXTV CC:
1. EXTV CC Left Open (or Grounded). This will cause INTV CC
to be powered from the internal 7.5V regulator resulting in
an efficiency penalty of up to 10% at high input voltages.
2. EXTV CC Connected directly to V OUT . This is the normal
connection for a 7.5V regulator and provides the highest
efficiency.
3. EXTV CC Connected to an External supply. If an external
supply is available in the 7.5V to 8.5V range, it may be used
to power EXTV CC providing it is compatible with the
MOSFET gate drive requirements.
4. EXTV CC Connected to an Output-Derived Boost Net-
work. For 3.3V and other low voltage regulators, efficiency
gains can still be realized by connecting EXTV CC to an
output-derived voltage that has been boosted to greater
3727fc
17
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相关代理商/技术参数 |
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| LTC3727EG-1#PBF | 功能描述:IC REG CTRLR BUCK 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:PolyPhase® 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 |
| LTC3727EG-1#TR | 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 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 |
| LTC3727EG-1#TRPBF | 功能描述:IC REG CTRLR BUCK 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:PolyPhase® 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 |
| LTC3727EG-1PBF | 制造商:Linear Technology 功能描述:DC-DC Controller Dual Step-Dn 36V SSOP28 |
| LTC3727EGPBF | 制造商:Linear Technology 功能描述:Dual Sync Buck Sw Vreg Controller SSOP28 |
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