參數(shù)資料
型號(hào): RT9202GS
廠(chǎng)商: Richtek Technology Corporation
英文描述: Single Synchronous Buck PWM DC-DC Controller
中文描述: 單同步降壓PWM DC - DC控制器
文件頁(yè)數(shù): 11/14頁(yè)
文件大?。?/td> 209K
代理商: RT9202GS
RT9202
11
DS9202-09 March 2007
www.richtek.com
V
OUT
Inductor
3.3V
2.5V
1.5V
2
μ
H
100mV
62mV
40mV
5
μ
H
40mV
25mV
16mV
2
μ
H
110mV
68mV
43mV
5
μ
H
44mV
28mV
18mV
2
μ
H
93mV
58mV
37mV
5
μ
H
37mV
23mV
15mV
1000
μ
F (ESR=53m
)
1500
μ
F (ESR=33m
)
3000
μ
F (ESR=21m
)
*Refer to Sanyo low ESR series (CE, DX, PX.....)
Table 1
The suggested L and C are as follows:
2
μ
H with
1500
μ
F C
OUT
5
μ
H with
1000
μ
F C
OUT
Figure 5
Input / Output Capacitor
High frequency/long life decoupling capacitors should be
placed as close to the power pins of the load as physically
possible. Be careful not to add inductance to the PCB
trace, as it could eliminate the performance from utilizing
these low inductance components. Consult with the
manufacturer of the load on specific decoupling
requirements.
The output capacitors are necessary for filtering output
and stabilizing the close loop (see the PWM loop stability).
For powering advanced, high-speed processors, it is
required to meet with the requirement of fast load
transient, high frequency capacitors with low ESR/ESL
capacitors are recommended.
Another concern is high ESR induced ripple may trigger
UV or OV protections.
PWM Loop Stability
The RT9202 is a voltage mode buck controller designed
for 5V step-down applications. The gain of error amplifier
is fixed at 35dB for simplified design.
The output amplitude of ramp oscillator is 1.75V, the loop
gain and loop pole/zero are calculated as follows :
DC loop gain G
A
=
LC filter pole P
O
=
Error Amp pole P
A
= 300kHz
ESR zero Z
O
=
The RT9202 Bode plot as shown Figure 6 is stable in
most of application conditions.
V
I
V
O
R
C
D
L
Q
C.C.M
T
ON
T
OFF
T
S
V
L
V
I
- V
O
- V
O
uQ
mI
L
I
L
= I
O
i
L
i
Q
I
Q
I
D
i
D
V
L
OUT
V
0.8
1.75
5
35dB
×
×
LC
2
1
p
ESRC
2
1
p
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相關(guān)代理商/技術(shù)參數(shù)
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RT9202PS 制造商:RICHTEK 制造商全稱(chēng):Richtek Technology Corporation 功能描述:Single Synchronous Buck PWM DC-DC Controller
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RT9203GS 制造商:RICHTEK 制造商全稱(chēng):Richtek Technology Corporation 功能描述:Dual Regulators - Synchronous Buck PWM DC-DC and Linear Controller