參數(shù)資料
型號: LT1611CS5
廠商: LINEAR TECHNOLOGY CORP
元件分類: 穩(wěn)壓器
英文描述: Isolated Flyback Switching Regulator with 9V Output
中文描述: 0.8 A SWITCHING REGULATOR, 1800 kHz SWITCHING FREQ-MAX, PDSO5
封裝: PLASTIC, SC-74A, SOT-23, 5 PIN
文件頁數(shù): 4/12頁
文件大小: 263K
代理商: LT1611CS5
4
LT1611
PI
FU
CTIO
N
S
U
U
SW (Pin 1):
Switch Pin. Minimize trace area at this pin to
keep EMI down.
GND (Pin 2):
Ground. Tie directly to local ground plane.
NFB (Pin 3):
Negative Feedback Pin. Minimize trace area.
Reference voltage is –1.23V. Connect resistive divider tap
here. The suggested value for R2 is 10k. Set R1 and R2
according to:
R
V
R
OUT
+
1
1 23
1 23
2
4 5 10
6
=
SHDN (Pin 4):
Shutdown Pin. Tie to 1V or more to enable
device. Ground to shut the device down.
V
IN
(Pin 5):
Input Supply Pin. Must be locally bypassed.
BLOCK DIAGRA
M
W
+
+
FF
R
Q
S
0.15
SW
DRIVER
COMPARATOR
2
SHUTDOWN
SHDN
4
1
+
Σ
RAMP
GENERATOR
R
C
C
C
1.4MHz
OSCILLATOR
GND
1611 BD
R6
40k
R4
140k
R3
30k
Q2
x10
Q1
Q3
R5
40k
V
IN
V
IN
5
NFB
C
PL
(OPTIONAL)
R2
(EXTERNAL)
R1
(EXTERNAL)
V
OUT
NFB
3
A2
A = 3
A1
g
m
OPERATIOU
The LT1611 combines a current mode, fixed frequency
PWM architecture with a –1.23V reference to directly
regulate negative outputs. Operation can be best under-
stood by referring to the block diagram of Figure 2. Q1 and
Q2 form a bandgap reference core whose loop is closed
around the output of the converter. The driven reference
point is the lower end of resistor R4, which normally sits
at a voltage of –1.23V. As the load current changes, the
NFB pin voltage also changes slightly, driving the output
of g
m
amplifier A1. Switch current is regulated directly on
a cycle-to-cycle basis by A1’s output. The flip-flop is set at
the beginning of each cycle, turning on the switch. When
the summation of a signal representing switch current and
a ramp generator (introduced to avoid subharmonic oscil-
lations at duty factors greater than 50%) exceeds the V
C
signal, comparator A2 changes stage, resetting the flip-
Figure 2
flop and turning off the switch. Output voltage decreases
(the magnitude increases) as switch current is increased.
The output, attenuated by external resistor divider R1 and
R2, appears at the NFB pin, closing the overall loop.
Frequency compensation is provided internally by R
C
and
C
C
. Transient response can be optimized by the addition of
a phase lead capacitor, C
PL
, in parallel with R1 in applica-
tions where large value or low ESR output capacitors are
used.
As load current is decreased, the switch turns on for a
shorter period each cycle. If the load current is further
decreased, the converter will skip cycles to maintain
output voltage regulation.
The LT1611 can work in either of two topologies. The
simpler topology appends a capacitive level shift to a
相關PDF資料
PDF描述
LT1613 1.4MHz, Single Cell DC/DC Converter in 5-Lead SOT-23
LT1613CS5 1.4MHz, Single Cell DC/DC Converter in 5-Lead SOT-23
LT1620 Controlled Current Battery Charging(控制電流的電池充電器)
LT1622 Low Input Voltage Current Mode Step-Down DC/DC Controller(低輸入電壓,電流模式步降DC/DC控制器)
LT1632 45MHz, 45V/us, Dual/Quad Rail-to-Rail Input and Output Precision Op Amps
相關代理商/技術參數(shù)
參數(shù)描述
LT1611CS5#PBF 制造商:Linear Technology 功能描述:Conv DC-DC Single Inv 0.9V to 10V 5-Pin TSOT-23 制造商:Linear Technology 功能描述:IC INVERTING REGULATOR 5-SOT-23 制造商:Linear Technology 功能描述:IC, INVERTING REGULATOR, 5-SOT-23 制造商:Linear Technology 功能描述:IC, INVERTING REGULATOR, 5-SOT-23; Primary Input Voltage:10V; No. of Outputs:1; Output Voltage:-5V; Output Current:150mA; No. of Pins:5; Operating Temperature Min:0C; Operating Temperature Max:70C; MSL:MSL 1 - Unlimited ;RoHS Compliant: Yes
LT1611CS5#TR 功能描述:IC REG INV ADJ 0.3A SOT23-5 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:2,500 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式,混合 頻率 - 開關:600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:帶卷 (TR) 供應商設備封裝:8-SOIC
LT1611CS5#TRM 功能描述:IC REG INV ADJ 0.3A SOT23-5 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:2,500 系列:- 類型:升壓(升壓) 輸出類型:可調(diào)式 輸出數(shù):1 輸出電壓:1.24 V ~ 30 V 輸入電壓:1.5 V ~ 12 V PWM 型:電流模式,混合 頻率 - 開關:600kHz 電流 - 輸出:500mA 同步整流器:無 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-SOIC(0.154",3.90mm 寬) 包裝:帶卷 (TR) 供應商設備封裝:8-SOIC
LT1611CS5#TRMPBF 功能描述:IC REG INV ADJ 0.3A SOT23-5 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩(wěn)壓器 - DC DC 開關穩(wěn)壓器 系列:- 標準包裝:250 系列:- 類型:降壓(降壓) 輸出類型:固定 輸出數(shù):1 輸出電壓:1.2V 輸入電壓:2.05 V ~ 6 V PWM 型:電壓模式 頻率 - 開關:2MHz 電流 - 輸出:500mA 同步整流器:是 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:6-UFDFN 包裝:帶卷 (TR) 供應商設備封裝:6-SON(1.45x1) 產(chǎn)品目錄頁面:1032 (CN2011-ZH PDF) 其它名稱:296-25628-2
LT1611CS5#TRMPBF 制造商:Linear Technology 功能描述:Switching Regulator IC