- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄385781 > RT9205AGS (Richtek Technology Corporation) Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller PDF資料下載
參數(shù)資料
| 型號： | RT9205AGS |
| 廠商： | Richtek Technology Corporation |
| 英文描述： | Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| 中文描述： | 雙穩(wěn)壓器-同步降壓PWM型DC - DC和線性控制器 |
| 文件頁數(shù)： | 13/15頁 |
| 文件大?。?/td> | 227K |
| 代理商： | RT9205AGS |
RT9205/A
Preliminary
13
DS9205/A-08 March 2007
www.richtek.com
Reference Voltage
Because RT9205/A uses a low 35dB gain error amplifier,
as shown in Figure 10. The voltage regulation is
dependent on V
IN
and V
OUT
settings. The FB reference
voltage of 0.8V were trimmed at V
IN
= 5V and V
OUT
= 2.5V.
In a fixed V
IN
= 5V application, the FB reference voltage
vs. V
OUT
voltage can be calculated as Figure 11.
Feedback Divider
The reference of RT9205/A is 0.8V. The output voltage can
be set using a resistor-divider as shown in Figure 12. Put
the R1 and R2 as close as possible to FB pin. R2 value
should be less than 1 k
to avoid noise coupling issue.
The C1 capacitor is a speed-up capacitor for reducing output
ripple to meet with the requirement of fast transient load.
Typically, value between 1nF and 0.1
μ
F is enough for C1.
PWM Layout Considerations
MOSFETs switch very fast in efficiency. The speed with
which the current transitions from one device to another
causes voltage spikes across the interconnecting
impedances and parasitic circuit elements. The voltage
spikes can degrade efficiency and radiate noise, that
results in over-voltage stress on devices. Careful the
layout for component placement layout and printed circuit
design can minimize the voltage spikes induced in the
converter. Consider, as an example, the turn-off transition
of the upper MOSFET prior to turn-off, the upper MOSFET
was carrying the full load current. During turn-off, current
stops flowing in the upper MOSFET and is picked up by
the lower MOSFET or Schottky diode. Any inductance in
the switched current path generates a large voltage spike
during the switching interval. Care with component
selections, layout of the critical components, and use
shorter and wider PCB traces that help in minimizing the
magnitude of voltage spikes.
There are two sets of critical components in a DC-DC
converter using the RT9205/A. The switching power
components are most critical because they switch large
amounts of energy, and as such, they tend to generate
equally large amounts of noise. The critical small signal
components are those connected to sensitive nodes or
those supplying critical bypass current.
Figure 11
Figure 10
+
+
-
PWM
I 3
56K
I 2
1K
+
-
FB
REP
0.8V
RAMP
1.75V
F
Duty (%)
80
70
60
20
30
40
50
0.82
0.78
0.80
0.81
0.79
10
90
VIN = 5V
×
FB
Duty - 50
V
= 0.8 - (
)
6.25mV
100
Figure 12
V
IN
+
R1
C1
FB
RT9205/A
V
OUT
L
R2
<1K
C
OUT
×
OUT
FB
R1
V
= V
(1+
)
R2
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| RT9205APS | Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9205GS | Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9205PS | Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9206GS | High Efficiency, Synchronous Buck with Dual Linear Controllers |
| RT9206PS | High Efficiency, Synchronous Buck with Dual Linear Controllers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| RT9205APS | 制造商:RICHTEK 制造商全稱:Richtek Technology Corporation 功能描述:Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9205GS | 制造商:RICHTEK 制造商全稱:Richtek Technology Corporation 功能描述:Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9205PS | 制造商:RICHTEK 制造商全稱:Richtek Technology Corporation 功能描述:Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller |
| RT9206 | 制造商:RICHTEK 制造商全稱:Richtek Technology Corporation 功能描述:High Efficiency, Synchronous Buck with Dual Linear Controllers |
| RT9206GS | 功能描述:IC REG TRPL BCK/LINEAR 16SOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性 + 切換式 系列:- 標準包裝:2,500 系列:- 拓撲:降壓（降壓）同步（3），線性（LDO）（2） 功能:任何功能 輸出數(shù):5 頻率 - 開關(guān):300kHz 電壓/電流 - 輸出 1:控制器 電壓/電流 - 輸出 2:控制器 電壓/電流 - 輸出 3:控制器 帶 LED 驅(qū)動器:無 帶監(jiān)控器:無 帶序列發(fā)生器:是 電源電壓:5.6 V ~ 24 V 工作溫度:-40°C ~ 85°C 安裝類型:* 封裝/外殼:* 供應商設(shè)備封裝:* 包裝:* |
發(fā)布緊急采購，3分鐘左右您將得到回復。