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参数资料
| 型号： | LT3512MPMS#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 11/26页 |
| 文件大小： | 0K |
| 描述： | IC REG FLYBK ISO ADJ .42A 16MSOP |
| 标准包装： | 2,500 |
| 类型： | 回扫，隔离 |
| 输出类型： | 可调式 |
| 输出数： | 1 |
| 输出电压： | 可调 |
| 输入电压： | 4.5 V ~ 100 V |
| PWM 型： | 电流模式，混合 |
| 频率 - 开关： | 40kHz ~ 650kHz |
| 电流 - 输出： | 420mA |
| 同步整流器： | 无 |
| 工作温度： | -55°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 16-TFSOP（0.118"，3.00mm），12 引线 |
| 包装： | 带卷 (TR) |
| 供应商设备封装： | 16-MSOP |
LT3512
APPLICATIONS INFORMATION
150V – V IN(MAX) – V LEAKAGE
V OUT + V F
t OFF(MIN) ? N PS ? ( V OUT + V F )
L PRI ≥
TRANSFORMERDESIGNCONSIDERATIONS
Successful application of the LT3512 relies on proper
transformer specification and design. Carefully consider
the following information in addition to the traditional
guidelines associated with high frequency isolated power
supply transformer design.
Linear Technology has worked with several leading mag-
netic component manufacturers to produce pre-designed
flyback transformers for use with the LT3512. Table 1
shows the details of these transformers.
Turns Ratio
Note that when using an R FB /R REF resistor ratio to set
output voltage, the user has relative freedom in selecting
a transformer turns ratio to suit a given application. In
contrast, the use of simple ratios of small integers, e.g.,
1:1, 2:1, 3:2, provides more freedom in setting total turns
and mutual inductance.
Typically, choose the transformer turns to maximize avail-
able output power. For low output voltages (3.3V or 5V), a
N:1 turns ratio can be used with multiple primary windings
relative to the secondary to maximize the transformer’s
current gain (and output power). However, remember that
the SW pin sees a voltage that is equal to the maximum
input supply voltage plus the output voltage multiplied by
the turns ratio. In addition, leakage inductance will cause
a voltage spike (V LEAKAGE ) on top of this reflected voltage.
This total quantity needs to remain below the absolute
maximum rating of the SW pin to prevent breakdown of
the internal power switch. Together these conditions place
an upper limit on the turns ratio, N, for a given application.
Choose a turns ratio low enough to ensure:
N <
For larger N:1 values, choose a transformer with a larger
physical size to deliver additional current. In addition,
choose a large enough inductance value to ensure that
the off-time is long enough to measure the output voltage.
For lower output power levels, choose a 1:1 or 1:N
transformer for the absolute smallest transformer size. A
1:N transformer will minimize the magnetizing inductance
(and minimize size), but will also limit the available output
power. A higher 1:N turns ratio makes it possible to have
very high output voltages without exceeding the breakdown
voltage of the internal power switch.
The turns ratio is an important element in the isolated
feedback scheme. Make sure the transformer manufacturer
guarantees turns ratio accuracy within ±1%.
Saturation Current
The current in the transformer windings should not ex-
ceed its rated saturation current. Energy injected once the
core is saturated will not be transferred to the secondary
and will instead be dissipated in the core. Information on
saturation current should be provided by the transformer
manufacturers. Table 1 lists the saturation current of the
transformers designed for use with the LT3512.
Primary Inductance Requirements
The LT3512 obtains output voltage information from the
reflected output voltage on the switch pin. The conduction
of secondary winding current reflects the output voltage
on the primary. The sampling circuitry needs a minimum
of 400ns to settle and sample the reflected output voltage.
In order to ensure proper sampling, the secondary winding
needs to conduct current for a minimum of 400ns. The
following equation gives the minimum value for primary-
side magnetizing inductance:
I PEAK(MIN)
t OFF(MIN) = 400ns
I PEAK(MIN) = 100mA
In addition to the primary inductance requirement for
sampling time, the LT3512 has internal circuit constraints
that prevent the switch from staying on for less than 100ns.
If the inductor current exceeds the desired current limit
3512fb
11
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| LT3513 | 制造商:LINER 制造商全称:Linear Technology 功能描述:2MHz High Current 5-Output Regulator for TFT-LCD Panels |
| LT3513EUHF#PBF | 功能描述:IC REG 5-OUT FOR TFT-LCD 38QFN RoHS:是 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 |
| LT3513EUHF#TRPBF | 功能描述:IC REG 5-OUT FOR TFT-LCD 38QFN RoHS:是 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 |
| LT3513EUHF-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2MHz High Current 5-Output Regulator for TFT-LCD Panels |
| LT3513EUHF-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:2MHz High Current 5-Output Regulator for TFT-LCD Panels |
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