- 您现在的位置：买卖IC网 > PDF目录15296 > LTC3713EG (Linear Technology)IC REG CTRLR BUCK PWM CM 24-SSOP PDF资料下载
参数资料
| 型号： | LTC3713EG |
| 厂商： | Linear Technology |
| 文件页数： | 17/24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
loss. For example, if R DS(ON) = 0.01 ? and R L = 0.005 ? , the
loss will range from 1% up to 10% as the output current
varies from 1A to 10A for a 1.5V output.
2. Transition loss. This loss arises from the brief amount
of time the top MOSFET spends in the saturated region
Design Example
As a design example, take a supply with the following
specifications: V IN = 1.8V to 3.3V, V OUT = 1.25V ± 100mV,
I OUT(MAX) = 6A, f = 300kHz. First, calculate the timing
resistor with V ON = V OUT :
during switch node transitions. It depends upon the input
voltage, load current, driver strength and MOSFET capaci-
tance, among other factors. The loss is significant at input
R ON =
( 2 . 5 V – 0 . 7 V )
( 2 . 5 V )( 300 kHz )( 10 pF )
= 240 k
voltages above 20V and can be estimated from:
Transition Loss ? (1.7A –1 ) V IN2 I OUT C RSS f
Next, use a standard value of 237k and choose the inductor
for about 40% ripple current at the maximum V IN :
? 1 –
? = 1 . 08 μ H
3. INTV CC current. This is the sum of the MOSFET driver
and control currents.
4. C IN loss. The input capacitor has the difficult job of
L =
1 . 25 V ?
( 300 kHz )( 0 . 4 )( 6 A ) ?
1 . 25 V ?
3 . 3 V ?
filtering the large RMS input current to the regulator. It
must have a very low ESR to minimize the AC I 2 R loss and
sufficient capacitance to prevent the RMS current from
Selecting a standard value of 1 μ H results in a maximum
ripple current of:
? 1 –
? = 2 . 6 A
causing additional upstream losses in fuses or batteries.
Other losses, including C OUT ESR loss, Schottky diode D1
? I L =
1 . 25 V ?
( 300 kHz )( 1 μ H ) ?
1 . 25 V ?
3 . 3 V ?
conduction loss during dead time and inductor core loss
I LIMIT ≥
+ ( 2 . 6 A ) = 10 . 2 A
generally account for less than 2% additional loss.
When making adjustments to improve efficiency, the input
current is the best indicator of changes in efficiency. If you
make a change and the input current decreases, then the
efficiency has increased. If there is no change in input
current, then there is no change in efficiency.
Checking Transient Response
The regulator loop response can be checked by looking
at the load transient response. Switching regulators take
several cycles to respond to a step in load current. When
a load step occurs, V OUT immediately shifts by an amount
equal to ? I LOAD (ESR), where ESR is the effective series
resistance of C OUT . ? I LOAD also begins to charge or
Next, choose the synchronous MOSFET switch. Choosing
an IRF7811A (R DS(ON) = 0.013 ? , C RSS = 60pF, θ JA =
50 ° C/W) yields a nominal sense voltage of:
V SNS(NOM) = (6A)(1.3)(0.013 ? ) = 101.4mV
Tying V RNG to 1V will set the current sense voltage range
for a nominal value of 100mV with current limit occurring
at 133mV. To check if the current limit is acceptable,
assume a junction temperature of about 10 ° C above a
50 ° C ambient with ρ 60 ° C = 1.15:
133 mV 1
( 1 . 15 )( 0 . 013 ? ) 2
and double check the assumed T J in the MOSFET:
3 . 3 V – 1 . 25 V ? 10 . 2 A ?
? ( 1 . 15 )( 0 . 013 ? )
?
discharge C OUT generating a feedback error signal used
by the regulator to return V OUT to its steady-state value.
During this recovery time, V OUT can be monitored for
overshoot or ringing that would indicate a stability
problem. The I TH pin external components shown in
P BOT
=
= 0 . 24 W
3 . 3 V ? 2 ?
2
Figure 1 will provide adequate compensation for most
applications. For a detailed explanation of switching
control loop theory see Application Note 76.
T J = 50 ° C + (0.24W)(50 ° C/W) = 62 ° C
Now check the power dissipation of the top MOSFET at
current limit with ρ 80 ° C = 1.3:
3713fa
17
相关PDF资料 |
PDF描述 |
|---|---|
| VE-27P-EW-F3 | CONVERTER MOD DC/DC 13.8V 100W |
| VE-27P-EW-F2 | CONVERTER MOD DC/DC 13.8V 100W |
| VE-27P-EW-F1 | CONVERTER MOD DC/DC 13.8V 100W |
| VE-27N-EY-B1 | CONVERTER MOD DC/DC 18.5V 50W |
| VE-27N-EW-F3 | CONVERTER MOD DC/DC 18.5V 100W |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 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) |
发布紧急采购，3分钟左右您将得到回复。