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参数资料
| 型号： | LTC3713EG |
| 厂商： | Linear Technology |
| 文件页数： | 12/24页 |
| 文件大小： | 0K |
| 描述： | IC REG CTRLR BUCK PWM CM 24-SSOP |
| 标准包装： | 59 |
| PWM 型： | 电流模式 |
| 输出数： | 1 |
| 频率 - 最大： | 1.5MHz |
| 占空比： | 90% |
| 电源电压： | 1.5 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： | 24-SSOP（0.209"，5.30mm 宽） |
| 包装： | 管件 |
LTC3713
APPLICATIO S I FOR ATIO
[ ]
f =
V OUT
The resulting power dissipation in the MOSFETs at maxi-
mum output current are:
P TOP = D TOP I OUT(MAX)2 ρ T(TOP) R DS(ON)(MAX)
+ k V IN2 I OUT(MAX) C RSS f
P BOT = D BOT I OUT(MAX)2 ρ T(BOT) R DS(ON)(MAX)
Both MOSFETs have I 2 R losses and the top MOSFET
includes an additional term for transition losses, which are
largest at high input voltages. The constant k = 1.7A –1 can
be used to estimate the amount of transition loss. The
bottom MOSFET losses are greatest when the bottom duty
cycle is near 100%, during a short-circuit or at high input
voltage.
Operating Frequency
Hz
V VON R ON ( 10 pF )
To hold frequency constant during output voltage changes,
tie the V ON pin to V OUT . The V ON pin has internal clamps
that limit its input to the one-shot timer. If the pin is tied
below 0.7V, the input to the one-shot is clamped at 0.7V.
Similarly, if the pin is tied above 2.4V, the input is clamped
at 2.4V.
Because the voltage at the I ON pin is about 0.7V, the
current into this pin is not exactly inversely proportional to
V IN , especially in applications with lower input voltages.
To account for the 0.7V drop on the I ON pin, the following
equation can be used to calculate the frequency:
The choice of operating frequency is a tradeoff between
efficiency and component size. Low frequency operation
f =
( V IN – 0 . 7 V ) V OUT
V VON ? V IN ? R ON ( 10 pF )
improves efficiency by reducing MOSFET switching losses
but requires larger inductance and/or capacitance in order
to maintain low output ripple voltage.
The operating frequency of LTC3713 applications is deter-
To correct for this error, an additional resistor R ON2
connected from the I ON pin to the 5V INTV CC supply will
further stabilize the frequency.
mined implicitly by the one-shot timer that controls the
on-time t ON of the top MOSFET switch. The on-time is set
R ON 2 =
5 V
0 . 7 V
R ON
by the current into the I ON pin and the voltage at the V ON
pin according to:
Changes in the load current magnitude will also cause
frequency shift. Parasitic resistance in the MOSFET
t ON =
V VON
I ION
( 10 pF )
switches and inductor reduce the effective voltage across
the inductance, resulting in increased duty cycle as the
load current increases. By lengthening the on-time slightly
Tying a resistor R ON from V IN to the I ON pin yields an on-
time inversely proportional to V IN . For a step-down
converter, this results in approximately constant fre-
quency operation as the input supply varies:
R VON1
30k
as current increases, constant frequency operation can be
maintained. This is accomplished with a resistive divider
from the I TH pin to the V ON pin and V OUT . The values
required will depend on the parasitic resistances in the
R VON1
3k
V OUT
R VON2
100k
R C
C VON
0.01 μ F
V ON
LTC3713
I TH
V OUT
INTV CC
10k
Q1
2N5087
R VON2
10k
C VON
0.01 μ F
R C
V ON
LTC3713
I TH
C C
(4a)
(4b)
C C
3713 F04
Figure 4. Adjusting Frequency Shift with Load Current Changes
3713fa
12
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| LTC3713EG#PBF | 功能描述:IC REG CTRLR BUCK PWM CM 24-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: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) |
| LTC3713EG#TR | 功能描述:IC REG CTRLR BUCK PWM CM 24-SSOP RoHS:否 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) |
| LTC3713EG#TRPBF | 功能描述:IC REG CTRLR BUCK PWM CM 24-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: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) |
| LTC3714EG | 功能描述:IC STP-DWN CNTRLR W/OPAMP 28SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:43 系列:- 应用:控制器，Intel VR11 输入电压:5 V ~ 12 V 输出数:1 输出电压:0.5 V ~ 1.6 V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:48-VFQFN 裸露焊盘 供应商设备封装:48-QFN（7x7） 包装:管件 |
| LTC3714EG#PBF | 功能描述:IC STP-DWN CNTRLR W/OPAMP 28SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 专用型 系列:- 标准包装:2,000 系列:- 应用:控制器，DSP 输入电压:4.5 V ~ 25 V 输出数:2 输出电压:最低可调至 1.2V 工作温度:-40°C ~ 85°C 安装类型:表面贴装 封装/外壳:30-TFSOP（0.173"，4.40mm 宽） 供应商设备封装:30-TSSOP 包装:带卷 (TR) |
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