- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄377737 > LTC1267CG-ADJ (LINEAR TECHNOLOGY CORP) RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS PDF資料下載
參數(shù)資料
| 型號： | LTC1267CG-ADJ |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | RADIATION HARDENED HIGH EFFICIENCY, 5 AMP SWITCHING REGULATORS |
| 中文描述： | 0.05 A DUAL SWITCHING CONTROLLER, 400 kHz SWITCHING FREQ-MAX, PDSO28 |
| 封裝： | PLASTIC, SSOP-28 |
| 文件頁數(shù)： | 8/16頁 |
| 文件大?。?/td> | 341K |
| 代理商： | LTC1267CG-ADJ |
8
LTC1267
LTC1267-ADJ/LTC1267-ADJ5
The LTC1267 Compared to the LTC1159, LTC1149 and
LTC1142 Family
The LTC1267 family is a dual LTC1159. Identical to the
LTC1159, the LTC1267 can reduce the quiescent and
shutdown currents by making use of an internal switch
which allows the driver and control sections to be
powered from an external source to improve efficiency.
The basic LTC1267 application circuit shown in Figure
1 is limited to a maximum input voltage of 30V due to
external MOSFET breakdown. If the application does
not require greater than 18V operation the LTC1142HV
should be used.
Component Selection
T
he basic LTC1267 application circuit is shown in Figure
1. External component selection is driven by the load
requirement and begins with the selection of R
SENSE
.
Once R
SENSE
is known, C
T
and L can be chosen. Next, the
power MOSFETs and diode are selected. Finally, C
IN
and
C
OUT
are selected and the loop is compensated. Since the
adjustable, 3.3V and 5V sections in the LTC1267 are
identical, the process of component selection is the same
for both sections.
R
SENSE
Selection for Output Current
R
SENSE
is chosen based on the required output current.
The LTC1267 current comparators have a threshold range
which extends from a minimum of 25mV/R
SENSE
to a
maximum of 150mV/R
SENSE
. The current comparator
threshold sets the peak of the inductor ripple current,
yielding a maximum output current I
MAX
equal to the peak
value less half the peak-to-peak ripple current. For proper
Burst Mode
operation, I
RIPPLE(P-P)
must be less than or
equal to the minimum current comparator threshold.
Since efficiency generally increases with ripple current,
the maximum allowable ripple current is assumed, i.e.,
I
RIPPLE(P-P)
= 25mV/R
SENSE
(see C
T
and L Selection for
Operating Frequency). Solving for R
SENSE
and allowing a
margin for variations in the LTC1267 and external compo-
nent values yields:
R
SENSE
= 100mV
I
MAX
APPLICATIU
W
U
U
The LTC1267 works well with values of R
SENSE
from
0.02
to 0.2
. Figure 2 shows the selection of R
SENSE
vs
maximum output current.
MAXIMUM OUTPUT CURRENT (A)
0
R
S
)
0.20
0.15
0.10
0.05
0
4
LTC1267 F02
1
2
3
5
Figure 2. Selecting R
SENSE
The load current below which Burst Mode
operation com-
mences, I
BURST
and the peak short-circuit current I
SC(PK)
both track I
MAX
. Once R
SENSE
has been chosen, I
BURST
and
I
SC(PK)
can be predicted from the following:
I
BURST
≈
15mV
R
SENSE
I
SC(PK)
= 150mV
R
SENSE
The LTC1267 automatically extends t
OFF
during a short
circuit to allow sufficient time for the inductor current to
decay between switch cycles. The resulting ripple current
causes the average short-circuit current I
SC(AVG)
to be
reduced to approximately I
MAX
.
C
T
and L Selection for Operating Frequency
Each regulator section of the LTC1267 uses a constant off-
time architecture with t
OFF
determined by an external
timing capacitor C
T
. The value of C
T
is calculated from the
desired continuous mode operating frequency (f
O
):
V
IN
)
C
T
=
1 –
7.8
×
10
–5
f
O
V
OUT
)
A graph for selecting C
T
vs frequency including the effects
of input voltage is given in Figure 3.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC1272-3CCN | 12-Bit, 3us, 250kHz Sampling A/D Converter |
| LTC1272 | 12-Bit, 3us, 250kHz Sampling A/D Converter |
| LTC1272-3ACN | 12-Bit, 3us, 250kHz Sampling A/D Converter |
| LTC1272-3ACS | 12-Bit, 3us, 250kHz Sampling A/D Converter |
| LTC1272-3CCS | 12-Bit, 3us, 250kHz Sampling A/D Converter |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC1272-3ACN | 功能描述:IC A/D CONV 12BIT SAMPLING 24DIP RoHS:否 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:- 位數(shù):12 采樣率（每秒）:300k 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:1 功率耗散（最大）:75mW 電壓電源:單電源 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:24-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:24-SOIC 包裝:帶卷 (TR) 輸入數(shù)目和類型:1 個(gè)單端，單極；1 個(gè)單端，雙極 |
| LTC1272-3ACN#PBF | 功能描述:IC A/D CONV 12BIT SAMPLING 24DIP RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:- 位數(shù):12 采樣率（每秒）:300k 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:1 功率耗散（最大）:75mW 電壓電源:單電源 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:24-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:24-SOIC 包裝:帶卷 (TR) 輸入數(shù)目和類型:1 個(gè)單端，單極；1 個(gè)單端，雙極 |
| LTC1272-3ACSW | 功能描述:IC A/D CONV 12BIT SAMPLNG 24SOIC RoHS:否 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 其它有關(guān)文件:TSA1204 View All Specifications 標(biāo)準(zhǔn)包裝:1 系列:- 位數(shù):12 采樣率（每秒）:20M 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:2 功率耗散（最大）:155mW 電壓電源:模擬和數(shù)字 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-TQFP 供應(yīng)商設(shè)備封裝:48-TQFP（7x7） 包裝:Digi-Reel® 輸入數(shù)目和類型:4 個(gè)單端，單極；2 個(gè)差分，單極 產(chǎn)品目錄頁面:1156 (CN2011-ZH PDF) 其它名稱:497-5435-6 |
| LTC1272-3ACSW#PBF | 功能描述:IC A/D CONV 12BIT SAMPLNG 24SOIC RoHS:是 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 其它有關(guān)文件:TSA1204 View All Specifications 標(biāo)準(zhǔn)包裝:1 系列:- 位數(shù):12 采樣率（每秒）:20M 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:2 功率耗散（最大）:155mW 電壓電源:模擬和數(shù)字 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:48-TQFP 供應(yīng)商設(shè)備封裝:48-TQFP（7x7） 包裝:Digi-Reel® 輸入數(shù)目和類型:4 個(gè)單端，單極；2 個(gè)差分，單極 產(chǎn)品目錄頁面:1156 (CN2011-ZH PDF) 其它名稱:497-5435-6 |
| LTC1272-3ACSW#TR | 功能描述:IC ADC 12BIT SAMPLING 24SOIC RoHS:否 類別:集成電路 (IC) >> 數(shù)據(jù)采集 - 模數(shù)轉(zhuǎn)換器 系列:- 標(biāo)準(zhǔn)包裝:1,000 系列:- 位數(shù):12 采樣率（每秒）:300k 數(shù)據(jù)接口:并聯(lián) 轉(zhuǎn)換器數(shù)目:1 功率耗散（最大）:75mW 電壓電源:單電源 工作溫度:0°C ~ 70°C 安裝類型:表面貼裝 封裝/外殼:24-SOIC（0.295"，7.50mm 寬） 供應(yīng)商設(shè)備封裝:24-SOIC 包裝:帶卷 (TR) 輸入數(shù)目和類型:1 個(gè)單端，單極；1 個(gè)單端，雙極 |
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。