- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄385505 > LTC1703CG (LINEAR TECHNOLOGY CORP) Synchronous 8-Bit Up/Down Binary Counters 24-PDIP 0 to 70 PDF資料下載
參數(shù)資料
| 型號： | LTC1703CG |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | Synchronous 8-Bit Up/Down Binary Counters 24-PDIP 0 to 70 |
| 中文描述： | 5 A DUAL SWITCHING CONTROLLER, 750 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | 0.209 INCH, PLASTIC, SSOP-28 |
| 文件頁數(shù)： | 23/36頁 |
| 文件大?。?/td> | 343K |
| 代理商： | LTC1703CG |
第1頁第2頁第3頁第4頁第5頁第6頁第7頁第8頁第9頁第10頁第11頁第12頁第13頁第14頁第15頁第16頁第17頁第18頁第19頁第20頁第21頁第22頁當(dāng)前第23頁第24頁第25頁第26頁第27頁第28頁第29頁第30頁第31頁第32頁第33頁第34頁第35頁第36頁
23
LTC1703
V(OUT) in degrees. Refer to your SPICE manual for details
of how to generate this plot.
*1703 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
*1703 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
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 10k
and R
B
varies depending on the VID code
selected.
;5 -> 3.3 for 3.3 VCC
;use if above lines fail
;ac stimulus
accurate results, but simulation can often get close enough
to give a working system. To measure the modulator gain
and phase directly, wire up a breadboard with an LTC1703
and the actual MOSFETs, inductor, and input and output
capacitors that the final design will use. This breadboard
should use appropriate construction techniques for high
speed analog circuitry: bypass capacitors located close to
the LTC1703, no long wires connecting components,
appropriately sized ground returns, etc. Wire the feedback
amplifier as a simple type 1 loop, with a 10k resistor from
V
OUT
to FB and a 0.1
μ
F feedback capacitor from COMP to
FB. Choose the bias resistor (R
B
) as required to set the
desired output voltage. Disconnect R
B
from ground and
connect it to a signal generator or to the source output of
a network analyzer (Figure 12) to inject a test signal into
the loop. Measure the gain and phase from the COMP pin
to the output node at the positive terminal of the output
capacitor. Make sure the analyzer’s input is AC coupled so
that the DC voltages present at both the COMP and V
OUT
nodes don’t corrupt the measurements or damage the
analyzer.
BOOST2
TG
SW
BG
FCB
FAULT
COMP
FB
RUN/SS
1/2 LTC1703
V
CC
10
MBR0530T
C
IN
5V
QT
1
μ
F
L
EXT
V
OUT
TO
ANALYZER
V
COMP
ANALYZER
AC
SOURCE
FROM
ANALYZER
QB
10
μ
F
0.1
μ
F
R
B
PV
CC
SGND PGND
+
+
10k
NC
C
OUT
1703 F12
+
Figure 12. Modulator Gain/Phase Measurement Set-Up
If breadboard measurement is not practical, a SPICE
simulation can be used to generate approximate gain/
phase curves. Plug the expected capacitor, inductor and
MOSFET values into the following SPICE deck and gener-
ate an AC plot of V(V
OUT
)/V(COMP) in dB and phase of
APPLICATIOU
W
U
U
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1704 | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| LTC1704B | Synchronous 8-Bit Up/Down Binary Counters 24-SOIC 0 to 70 |
| LTC1705 | Dual 550kHz Synchronous Switching Regulator Controller with 5-Bit VID and 150mA LDO |
| LTC1705EGN | Dual 550kHz Synchronous Switching Regulator Controller with 5-Bit VID and 150mA LDO |
| LTC1710 | Synchronous 8-Bit Up/Down Binary Counters 24-PDIP 0 to 70 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1703CG#PBF | 功能描述:IC REG SW DUAL SYNC VID 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:2,000 系列:- 應(yīng)用:控制器，DSP 輸入電壓:4.5 V ~ 25 V 輸出數(shù):2 輸出電壓:最低可調(diào)至 1.2V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:30-TFSOP（0.173"，4.40mm 寬） 供應(yīng)商設(shè)備封裝:30-TSSOP 包裝:帶卷 (TR) |
| LTC1703CG#TR | 制造商:Linear Technology 功能描述:LDO Cntrlr REG CTRLR 0.9V to 2V 28-Pin SSOP T/R |
| LTC1703CG#TRPBF | 功能描述:IC REG SW DUAL SYNC VID 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
| LTC1703IG | 功能描述:IC REG SW DL SYNC W/VID 28-SSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
| LTC1703IG#PBF | 功能描述:IC REG SW DUAL SYNC VID 28SSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - 專用型 系列:- 標準包裝:43 系列:- 應(yīng)用:控制器，Intel VR11 輸入電壓:5 V ~ 12 V 輸出數(shù):1 輸出電壓:0.5 V ~ 1.6 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-VFQFN 裸露焊盤 供應(yīng)商設(shè)備封裝:48-QFN（7x7） 包裝:管件 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。