參數(shù)資料
型號: LTC1873EG
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: Quadruple 2-Input Positive-AND Gate 14-TSSOP -40 to 85
中文描述: 5 A SWITCHING CONTROLLER, 750 kHz SWITCHING FREQ-MAX, PDSO28
封裝: 0.209 INCH, PLASTIC, SSOP-28
文件頁數(shù): 23/32頁
文件大小: 308K
代理商: LTC1873EG
23
LTC1873
Now calculate the remaining values:
(K is a constant used in the calculations)
= chosen crossover frequency
G = 10
(GAIN/20)
(this converts GAIN in dB to G in absolute
gain)
Type 2 Loop:
K
TanBOOST
1
2
2
C
GKR
2
C
C K
R
K
C
R
V
R
( )
V
V
B
REF
OUT
REF
=
+
°
=
=
(
π
)
=
π
=
2
45
2
1
1
1
2
2
1
1
Type 3 Loop:
K
Tan
BOOST
4
C
GR
C
C K
2
R
K
C
1
R
R
K
C
KR
R
( )
R
V
V
V
B
REF
OUT
REF
=
+
°
1
=
=
(
π
)
=
π
=
(
)
=
π
=
2
45
2
2
1
1
1
2
2
1
3
1
3
1
2
3
1
V(OUT) in degrees. Refer to your SPICE manual for details
of how to generate this plot.
*1873 modulator gain/phase
*
1999 Linear Technology
*this file written to run with PSpice 8.0
*may require modifications for other SPICE
simulators
*MOSFETs
rfet mod sw 0.02
;MOSFET rdson
*inductor
lext sw out1 1u
rl out1 out 0.005
;inductor value
;inductor series R
*output cap
cout out out2 1000u
resr out2 0 0.01
;capacitor value
;capacitor ESR
*1873 internals
emod mod 0 laplace {v(comp)} =
+ {5*exp(–s*909e–9)}
*emod mod 0 comp 0 5
vstim comp 0 0 ac 1
.ac dec 100 1k 1meg
.probe
.end
;5 -> 3.3 for 3.3 VCC
;use if above lines fail
;ac stimulus
With the gain/phase plot in hand, a loop crossover fre-
quency can be chosen. Usually the curves look something
like Figure 8. Choose the crossover frequency in the rising
or flat parts of the phase curve, beyond the external LC
poles. Frequencies between 10kHz and 50kHz usually
work well. Note the gain (GAIN, in dB) and phase (PHASE,
in degrees) at this point. The desired feedback amplifier
gain will be –GAIN to make the loop gain 0dB at this
frequency. Now calculate the needed phase boost, assum-
ing 60
°
as a target phase margin:
BOOST = –(PHASE + 30
°
)
If the required BOOST is less than 60
°
, a type 2 loop can
be used successfully, saving two external components.
BOOST values greater than 60
°
usually require type 3
loops for satisfactory performance.
Finally, choose a convenient resistor value for R1 (10k is
usually a good value). Note that channel 1 includes R1 and
R
B
internally as part of the VID DAC circuitry. R1 is fixed
at 20k and R
B
varies depending on the VID code selected.
APPLICATIOU
W
U
U
相關(guān)PDF資料
PDF描述
LTC1873 Dual 550kHz Synchronous 2-Phase Switching Regulator Controller with 5-Bit VID(550kHz,雙 路,同步2相開關(guān)穩(wěn)壓器(帶5位VID))
LTC1874 Dual Constant Frequency Current Mode Step-Down DC/DC Controller(雙路(3.3V,1.8V輸出)恒定頻率,電流模式,步降DC/DC控制器)
LTC1874EGN Quadruple 2-Input Positive-AND Gate 14-VQFN -40 to 85
LTC1875 15mA Quiescent Current 1.5A Monolithic Synchronous Step-Down Regulator
LTC1875EGN 15mA Quiescent Current 1.5A Monolithic Synchronous Step-Down Regulator
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LTC1873EG#PBF 功能描述:IC REG CTRLR BUCK PWM VM 28-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1873EG#TR 功能描述:IC REG CTRLR BUCK PWM VM 28-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1873EG#TRPBF 功能描述:IC REG CTRLR BUCK PWM VM 28-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:4,500 系列:PowerWise® PWM 型:控制器 輸出數(shù):1 頻率 - 最大:1MHz 占空比:95% 電源電壓:2.8 V ~ 5.5 V 降壓:是 升壓:無 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:6-WDFN 裸露焊盤 包裝:帶卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名稱:LM1771SSDX
LTC1874EGN 功能描述:IC REG CTRLR BUCK PWM CM 16-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)
LTC1874EGN#PBF 功能描述:IC REG CTRLR BUCK PWM CM 16-SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 切換控制器 系列:- 標(biāo)準(zhǔn)包裝:2,500 系列:- PWM 型:電流模式 輸出數(shù):1 頻率 - 最大:500kHz 占空比:96% 電源電壓:4 V ~ 36 V 降壓:無 升壓:是 回掃:無 反相:無 倍增器:無 除法器:無 Cuk:無 隔離:無 工作溫度:-40°C ~ 125°C 封裝/外殼:24-WQFN 裸露焊盤 包裝:帶卷 (TR)