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參數(shù)資料
| 型號： | LNK302DG |
| 廠商： | POWER INTEGRATIONS INC |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.2 A SWITCHING REGULATOR, 70 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | PLASTIC SURFACE MOUNT, DIP-8 |
| 文件頁數(shù)： | 18/20頁 |
| 文件大小： | 706K |
| 代理商： | LNK302DG |
2-7
LNK302/304-306
7
Rev. I 11/08
Table 2 (cont). Common Circuit Congurations Using LinkSwitch-TN.
TOPOLOGY
BASIC CIRCUIT SCHEMATIC
KEY FEATURES
Low-Side
Buck Boost –
Optocoupler
Feedback
1. Output referenced to input
2. Positive output (V
O) with respect to +VIN
3. Step up/down – V
O > VIN or VO < VIN
4. Optocoupler feedback
- Accuracy only limited by reference
choice
- Low cost non-safety rated opto
- No pre-load required
5. Fail-safe – output is not subjected to input
voltage if the internal MOSFET fails
provides the lowest cost and highest efciency converter. CCM
designs require a larger inductor and ultra-fast (t
rr ≤35 ns)
freewheeling diode in all cases. It is lower cost to use a larger
LinkSwitch-TN in MDCM than a smaller LinkSwitch-TN in CCM
because of the additional external component costs of a CCM
design. However, if the highest output current is required, CCM
should be employed following the guidelines below.
Topology Options
LinkSwitch-TN can be used in all common topologies, with or
without an optocoupler and reference to improve output voltage
tolerance and regulation. Table 2 provide a summary of these
congurations. For more information see the Application
Note – LinkSwitch-TN Design Guide.
Component Selection
Referring to Figure 5, the following considerations may be
helpful in selecting components for a LinkSwitch-TN design.
Freewheeling Diode D1
Diode D1 should be an ultra-fast type. For MDCM, reverse
recovery time t
rr ≤75 ns should be used at a temperature of
70
°C or below. Slower diodes are not acceptable, as continuous
mode operation will always occur during startup, causing high
leading edge current spikes, terminating the switching cycle
prematurely, and preventing the output from reaching regulation.
If the ambient temperature is above 70
°C then a diode with
t
rr ≤35 ns should be used.
For CCM an ultra-fast diode with reverse recovery time
t
rr ≤35 ns should be used. A slower diode may cause excessive
leading edge current spikes, terminating the switching cycle
prematurely and preventing full power delivery.
Fast and slow diodes should never be used as the large reverse
recovery currents can cause excessive power dissipation in the
diode and/or exceed the maximum drain current specication
of LinkSwitch-TN.
Feedback Diode D2
Diode D2 can be a low-cost slow diode such as the 1N400X
series, however it should be specied as a glass passivated type
to guarantee a specied reverse recovery time. To a rst order,
the forward drops of D1 and D2 should match.
Inductor L1
Choose any standard off-the-shelf inductor that meets the
design requirements. A “drum” or “dog bone” “I” core
inductor is recommended with a single ferrite element due to
its low cost and very low audible noise properties. The typical
inductance value and RMS current rating can be obtained from
the LinkSwitch-TN design spreadsheet available within the
PI Expert design suite from Power Integrations. Choose L1
greater than or equal to the typical calculated inductance with
RMS current rating greater than or equal to calculated RMS
inductor current.
Capacitor C2
The primary function of capacitor C2 is to smooth the inductor
current. The actual output ripple voltage is a function of this
capacitor’s ESR. To a rst order, the ESR of this capacitor
should not exceed the rated ripple voltage divided by the typical
current limit of the chosen LinkSwitch-TN.
Feedback Resistors R1 and R3
The values of the resistors in the resistor divider formed by
R1 and R3 are selected to maintain 1.65 V at the FB pin. It is
recommended that R3 be chosen as a standard 1% resistor of
2 k
Ω. Thisensuresgoodnoiseimmunitybybiasingthefeedback
network with a current of approximately 0.8 mA.
Feedback Capacitor C3
Capacitor C3 can be a low cost general purpose capacitor. It
provides a “sample and hold” function, charging to the output
voltage during the off time of LinkSwitch-TN. Its value should
be 10
μF to 22 μF; smaller values cause poorer regulation at
light load conditions.
LinkSwitch-TN
PI-3756-111903
+
BP
FB
D
S
V
O
V
IN
+
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LNK302DGTL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:LinkSwitch-TN Family Lowest Component Count, Energy-Effi cient Off-Line Switcher IC |
| LNK302DG-TL | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 63 mA (MDCM) 80 mA (CCM) RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
| LNK302DN | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 63 mA (MDCM) 80 mA (CCM) RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
| LNK302DNTL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:LinkSwitch-TN Family Lowest Component Count, Energy-Effi cient Off-Line Switcher IC |
| LNK302DN-TL | 功能描述:交流/直流開關(guān)轉(zhuǎn)換器 63 mA (MDCM) 80 mA (CCM) RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關(guān)頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
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