參數(shù)資料
型號(hào)： LT3150
廠商： Linear Technology Corporation
英文描述： Fast Transient Response, Low Input Voltage, Very Low Dropout Linear Regulator Controller
中文描述： 快速瞬態(tài)響應(yīng)，低輸入電壓，非常低壓差線性穩(wěn)壓器控制器
文件頁(yè)數(shù)： 16/20頁(yè)
文件大?。?/td> 263K
代理商： LT3150
16
LT3150
3150f
APPLICATIOU
W
U
U
Figure 4. Typical Bode Plot for
Low ESR Ceramic Output Capacitors
G
FREQUENCY (Hz)
MANY HIGH ORDER POLES AND
ZEROS PAST UNITY-GAIN f
X
V
REF
V
OUT
P2 IS A FUNCTION
OF LOAD CURRENT
I
LOAD(MIN)
I
LOAD(MAX)
3150 F04
AV1 = g
m1
R1 (V
REF
/V
OUT
)
AVOL = g
m1
R
O
(V
REF
/V
OUT
)
Z1 = 1/(2
π
R1 C1)
P2 = g
m
(Q1)/(2
π
C
O
)
P1 = 1/(2
π
R
O
C1)
f
X
= g
m1
R1
g
m
(Q1)
2
π
C
O
G
FREQUENCY (Hz)
MANY HIGH ORDER POLES AND
ZEROS PAST UNITY-GAIN f
X
g
m1
2
π
C1
P2 IS A FUNCTION
OF LOAD CURRENT
I
LOAD(MIN)
I
LOAD(MAX)
3150 F05
AV1 = AVOL (P1/P2)
= (g
m1
C
O
)/(g
m
(Q1) C1)
AVOL = g
m1
R
O
(V
REF
/V
OUT
)
Z1 = 1/(2
π
ESR C
O
)
P2 = g
m
(Q1)/(2
π
C
O
)
P1 = 1/(2
π
R
O
C1)
f
X
=
Figure 5. Typical Bode Plot for Tantalum
or Electrolytic Output Capacitors
higher unity gain bandwidth crossover frequency, f
X
. f
X
must be set to a value that provides adequate phase and
gain margin and this criteria limits the shelf gain value. If
higher shelf gain is required for a given application, then
increase output capacitance.
In both output capacitor cases, the location of the second
pole, P2, is set by the MOSFET’s transconductance, g
m
(Q1),
and the value of the output capacitor, C
O
. The output load
current sets the transconductance of the MOSFET. P2
moves as a function of load current and consequently, so
does the unity-gain crossover frequency, f
X
. Figures 4 and
5 depict this behavior. At very low output currents, P2’s
location moves to a very low frequency. Therefore, set Z1
at a low enough frequency to provide adequate phase boost.
A temptation is to set Z1’s value equal to P2’s value at
minimum output load current. The bode plot then exhibits
a single pole response at minimum output current. How-
ever, this either makes the “shelf gain” and f
X
too high for
stability or it makes the small signal settling time very long.
Set Z1 above the minimum value for P2 so that at small
output load currents, the second pole P2 occurs and then
Z1 provides phase boost prior to crossing unity gain.
At the highest load current levels, several poles and zeros
exist just beyond the unity-gain crossover frequency.
Sometimes, the gain peaks back above unity and a high
frequency, low level oscillation appears. A high frequency
pole is necessary to roll off the response. In the case of
ceramic output capacitors, capacitor C2 in Figure 4 sets
this pole in combination with R1. In the case of electrolytic
or tantalum output capacitors, some small ceramic ca-
pacitors in parallel with the main output capacitors usually
provide the desired response.
Finally, look for very high frequency gate oscillations in the
range of 2MHz to 10MHz. Small MOSFETs with low gate
capacitance are most susceptible to this issue. This oscil-
lation is typically caused by the MOSFET’s “effective” gate
capacitance and the MOSFET’s parasitic source induc-
tance resonating. The MOSFET’s source inductance is the
sum of the device’s bond wire plus package lead induc-
tance and the PCB trace inductance between the MOSFET’s
source and the actual output capacitors. Although the
MOSFET’s internal inductance is fixed, proper PCB layout
techniques minimize the external inductance. Minimize
the distance between the MOSFET’s source and the output
decoupling capacitors and run wide planes if possible.
Connect the top of the feedback divider at the point closest
to the actual load rather than the MOSFET source. If high
frequency oscillations persist, a small value resistor in the
range of 1
to 50
in series with the gate of the MOSFET
typically eliminates this ringing. The inclusion of a gate
resistor may permit the high frequency pole discussed in
the preceding paragraph to be eliminated or fine tuned.
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參數(shù)描述
LT3150CGN 功能描述:IC REG CTRLR SGL POS ADJ 16-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性晶體管驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:More Information on LDOs 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:正，固定式 輸出數(shù):2 輸出電壓:2.8V，3.3V 電流 - 電源:12mA 輸入電壓:5 V ~ 22 V 工作溫度:0°C ~ 70°C 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:16-SOIC 包裝:帶卷 (TR)
LT3150CGN#PBF 功能描述:IC REG CTRLR SGL POS ADJ 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性晶體管驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:More Information on LDOs 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:正，固定式 輸出數(shù):2 輸出電壓:2.8V，3.3V 電流 - 電源:12mA 輸入電壓:5 V ~ 22 V 工作溫度:0°C ~ 70°C 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:16-SOIC 包裝:帶卷 (TR)
LT3150CGN#TR 功能描述:IC REG CTRLR SGL POS ADJ 16SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性晶體管驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:More Information on LDOs 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:正，固定式 輸出數(shù):2 輸出電壓:2.8V，3.3V 電流 - 電源:12mA 輸入電壓:5 V ~ 22 V 工作溫度:0°C ~ 70°C 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:16-SOIC 包裝:帶卷 (TR)
LT3150CGN#TRPBF 功能描述:IC REG CTRLR SGL POS ADJ 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 線性晶體管驅(qū)動(dòng)器 系列:- 產(chǎn)品培訓(xùn)模塊:More Information on LDOs 標(biāo)準(zhǔn)包裝:2,500 系列:- 類型:正，固定式 輸出數(shù):2 輸出電壓:2.8V，3.3V 電流 - 電源:12mA 輸入電壓:5 V ~ 22 V 工作溫度:0°C ~ 70°C 封裝/外殼:16-SOIC（0.154"，3.90mm 寬） 供應(yīng)商設(shè)備封裝:16-SOIC 包裝:帶卷 (TR)
LT317 制造商:LINER 制造商全稱:Linear Technology 功能描述:Positive Adjustable Regulator
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