參數(shù)資料
型號(hào): DS232AS
廠商: DALLAS SEMICONDUCTOR
元件分類(lèi): Line Driver or Receiver
英文描述: LINE TRANSCEIVER, PDSO16
封裝: 0.300 INCH, SOIC-16
文件頁(yè)數(shù): 14/28頁(yè)
文件大?。?/td> 581K
代理商: DS232AS
MAX15023
Wide 4.5V to 28V Input, Dual-Output
Synchronous Buck Controller
21
Maxim Integrated
Type III Compensation Network
(See Figure 5)
If the output capacitor used is a low-ESR tantalum or
ceramic type, the ESR-induced zero frequency is usual-
ly above the targeted zero crossover frequency (fO). In
this case, Type III compensation is recommended.
Type III compensation provides three poles and two
zeros at the following frequencies:
Two midband zeros (fZ1 and fZ2) cancel the pair of
complex poles introduced by the LC filter:
fP1 = 0
fP1 introduces a pole at zero frequency (integrator) for
nulling DC output voltage errors:
Depending on the location of the ESR zero (fZO), fP2
can be used to cancel it, or to provide additional atten-
uation of the high-frequency output ripple:
fP3 attenuates the high-frequency output ripple.
The locations of the zeros and poles should be such
that the phase margin peaks around fO.
Ensure that RF>>2/gm (1/gm(MIN) = 1/600S = 1.67k)
and the parallel resistance of R1, R2, and RI is greater
than 1/gm. Otherwise, a 180° phase shift is introduced
to the response and will make it unstable.
The following procedure is recommended:
1) With RF ≥ 10k, place the first zero (fZ1) at 0.5 x
fPO:
so:
2) The gain of the modulator (GainMOD)—composed of
the regulator’s pulse-width modulator, LC filter,
feedback divider, and associated circuitry at
crossover frequency is:
The gain of the error amplifier (GainEA) in midband fre-
quencies is:
The total loop gain as the product of the modulator gain
and the error amplifier gain at fO should be equal to 1.
So:
Therefore:
Solving for CI:
3) If fPO < fO < fZO < fSW/2, the second pole (fP2)
should be used to cancel fZO. This way, the Bode
plot of the loop gain plot does not flatten out soon
after the 0dB crossover, and maintains its
-20dB/decade slope up to 1/2 the switching frequen-
cy. This is likely to occur if the output capacitor is a
low-ESR tantalum or polymer. Then set:
fP2 = fZO
If a ceramic capacitor is used, then the capacitor ESR
zero, fZO, is likely to be located even above 1/2 the
switching frequency, that is, fPO < fO< fSW/2 < fZO. In
this case, the frequency of the second pole (fP2) should
be placed high enough in order not to significantly
erode the phase margin at the crossover frequency. For
example, it can be set at 5 x fO, so that its contribution
to phase loss at the crossover frequency, fO, is only
about 11°:
fP2 = 5 x fO
Once fP2 is known, calculate RI:
R
fC
I
PI
=
××
1
2
π
C
Vf
L
C
VR
I
OSC
O
OUT
IN
F
=
××
×
()
×
2
π
V
fC
L
fC
R
IN
OSC
O
OUT
OI
F
×
××
×
×××
=
1
2
21
2
()
π
Gain
MOD
EA
×= 1
Gain
f
C
R
EA
O
I
F
=
×××
2
π
Gain
V
fL
C
MOD
IN
OSC
O
OUT
××
×
1
2
()
π
C
Rf
F
FPO
=
××
×
1
20 5
π
.
f
RC
f
Z
FF
PO
1
2
05
=
××
π
.
f
R
CC
P
F
FCF
3
1
2
=
××
×
+
π
f
RC
P
II
2
1
2
=
××
π
f
RC
f
CR
R
Z
FF
Z
II
1
2
1
2
1
2
=
××
=
××
+
π
()
相關(guān)PDF資料
PDF描述
DS232A LINE TRANSCEIVER, PDIP16
DS2404S-001 0 TIMER(S), REAL TIME CLOCK, PDSO16
DS2404B 0 TIMER(S), REAL TIME CLOCK, PDSO16
DS2404 0 TIMER(S), REAL TIME CLOCK, PDIP16
DS2405P SPECIALTY MEMORY CIRCUIT, PDSO6
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS232AS/T&R 制造商:Maxim Integrated Products 功能描述:IC TXRX DUAL RS-232 5V 16-SOIC
DS232AS/T&R 功能描述:RS-232接口集成電路 RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝:
DS232AS+ 功能描述:RS-232接口集成電路 Dual RS-232 Transmitter/Receiver RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝:
DS232AS+T&R 制造商:Maxim Integrated Products 功能描述:IC TXRX DUAL RS-232 5V 16-SOIC
DS232AS+T&R 功能描述:RS-232接口集成電路 RoHS:否 制造商:Exar 數(shù)據(jù)速率:52 Mbps 工作電源電壓:5 V 電源電流:300 mA 工作溫度范圍:- 40 C to + 85 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:LQFP-100 封裝: