参数资料
型号: LTC1438XCG
厂商: Linear Technology
文件页数: 1/32页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM CM 28-SSOP
标准包装: 47
PWM 型: 电流模式
输出数: 2
频率 - 最大: 138kHz
占空比: 99%
电源电压: 3.5 V ~ 30 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: 0°C ~ 70°C
封装/外壳: 28-SSOP(0.209",5.30mm 宽)
包装: 管件
LTC1438/LTC1439
Dual High Efficiency,
Low Noise, Synchronous
Step-Down Switching Regulators
FEATURES
DESCRIPTIO
Maintains Constant Frequency at Low Output
Currents
Dual N-Channel MOSFET Synchronous Drive
Programmable Fixed Frequency (PLL Lockable)
Wide V IN Range: 3.5V to 36V Operation
Ultrahigh Efficiency
Very Low Dropout Operation: 99% Duty Cycle
Low Dropout, 0.5A Linear Regulator for VPP
Generation or Low Noise Audio Supply
Built-In Power-On Reset Timer
Programmable Soft Start
Low-Battery Detector
Remote Output Voltage Sense
Foldback Current Limiting (Optional)
Pin Selectable Output Voltage
Logic-Controlled Micropower Shutdown: I Q < 30 μ A
Output Voltages from 1.19V to 9V
Available in 28- and 36-Lead SSOP Packages
The LTC ? 1438/LTC1439 are dual, synchronous step-
down switching regulator controllers which drive external
N-channel power MOSFETs in a phase-lockable fixed
frequency architecture. The Adaptive Power TM output stage
selectively drives two N-channel MOSFETs at frequencies
up to 400kHz while reducing switching losses to maintain
high efficiencies at low output currents.
An auxiliary 0.5A linear regulator using an external PNP
pass device provides a low noise, low dropout voltage
source. A secondary winding feedback control pin (SFB1)
guarantees regulation regardless of load on the main
output by forcing continuous operation.
An additional comparator is available for use as a low
battery detector. A power-on reset timer (POR) is included
which generates a signal delayed by 65536/f CLK (typ
300ms) after the output is within 5% of the regulated
output voltage. Internal resistive dividers provide pin
selectable output voltages with remote sense capability on
APPLICATIO S
one of the two outputs.
Notebook and Palmtop Computers, PDAs
Portable Instruments
Battery-Operated Devices
DC Power Distribution Systems
The operating current levels are user-programmable via
external current sense resistors. Wide input supply range
allows operation from 3.5V to 30V (36V maximum).
, LTC and LT are registered trademarks of Linear Technology Corporation. Adaptive
Power is a trademark of Linear Technology Corporation. All other trademarks are the prop-
erty of their respective owners. Protected by U.S. Patents including 5481178, 6304066,
5929620, 6580258, 5705919, 5731731.
TYPICAL APPLICATIO
V IN
D B1 , CMDSH-3
BOOST 1
V PROG1
V IN
INTV CC
D B2 , CMDSH-3
BOOST 2
+
4.7 μ F
16V
+
C IN
22 μ F
35V
× 4
5.2V TO 28V
M1
TGL1
TGL2
M4
L1
10 μ H
D1
MBR140T3
M3*
M2
C B1
0.1 μ F
TGS1
SW1
BG1
LTC1439
TGS2
SW2
BG2
SENSE + 2
C B2 , 0.1 μ F
M5
M6*
L2
10 μ H
D2
MBR140T3
V OUT1
5V
3.5A
+
R SENSE1
0.03 ?
C OUT1
220 μ F
10V
1000pF
C C1
1000pF
C C1A
220pF
SENSE + 1
SENSE – 1
I TH1
RUN/SS1
R C1 C SS1
10k 0.1 μ F
C OSC
V PROG2
C OSC
56pF
SGND
SENSE – 2
V OSENSE2
I TH2
PGND RUN/SS2
C SS2
0.1 μ F
1000pF
C C2
1000pF
R C2
10k
C C2A
470pF
+
R SENSE2
0.03 ?
V OUT2
3.3V
3.5A
C OUT
220 μ F
10V
M1, M2, M4, M5: Si4412ADY
M3, M6: IRLML2803
*NOT REQUIRED FOR LTC1438
BOLD LINES INDICATE HIGH CURRENT PATHS
1438 F01
Figure 1. High Efficiency Dual 5V/3V Step-Down Converter
14389fb
1
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LTC1438XCG#PBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1438XCG#TR 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1438XCG#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 28-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:4,500 系列:PowerWise® PWM 型:控制器 输出数:1 频率 - 最大:1MHz 占空比:95% 电源电压:2.8 V ~ 5.5 V 降压:是 升压:无 回扫:无 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 125°C 封装/外壳:6-WDFN 裸露焊盘 包装:带卷 (TR) 配用:LM1771EVAL-ND - BOARD EVALUATION LM1771 其它名称:LM1771SSDX
LTC1439CG 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:否 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:8-TSSOP(0.173",4.40mm 宽) 包装:带卷 (TR)
LTC1439CG#PBF 功能描述:IC REG CTRLR BUCK PWM CM 36-SSOP RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:- 标准包装:2,000 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:1MHz 占空比:50% 电源电压:9 V ~ 10 V 降压:无 升压:是 回扫:是 反相:无 倍增器:无 除法器:无 Cuk:无 隔离:无 工作温度:-40°C ~ 85°C 封装/外壳:8-TSSOP(0.173",4.40mm 宽) 包装:带卷 (TR)