参数资料
型号: LTC3868EUFD-1#TRPBF
厂商: Linear Technology
文件页数: 1/38页
文件大小: 0K
描述: IC REG CTRLR BUCK PWM CM 28-QFN
标准包装: 2,500
系列: PolyPhase®
PWM 型: 电流模式
输出数: 2
频率 - 最大: 850kHz
占空比: 99.4%
电源电压: 4 V ~ 24 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -40°C ~ 85°C
封装/外壳: 28-WFQFN 裸露焊盘
包装: 带卷 (TR)
LTC3868-1
Low I Q , Dual
2-Phase Synchronous
Step-Down Controller
FEATURES
DESCRIPTION
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Low Operating I Q : 170μA (One Channel On)
Wide Output Voltage Range: 0.8V ≤ V OUT ≤ 14V
Wide V IN Range: 4V to 24V
R SENSE or DCR Current Sensing
Out-of-Phase Controllers Reduce Required Input
Capacitance and Power Supply Induced Noise
OPTI-LOOP ? Compensation Minimizes C OUT
Phase-Lockable Frequency (75kHz to 850kHz)
Programmable Fixed Frequency (50kHz to 900kHz)
Selectable Continuous, Pulse-Skipping or
Burst Mode ? Operation at Light Loads
Very Low Dropout Operation: 99% Duty Cycle
Adjustable Output Voltage Soft-Start
Power Good Output Voltage Monitor
Output Overvoltage Protection
Output Latchoff Protection During Short Circuit
Low Shutdown I Q : 8μA
Internal LDO Powers Gate Drive from V IN or EXTV CC
No Current Foldback During Start-Up
Small 4mm × 5mm QFN and Narrow SSOP Packages
The LTC ? 3868-1 is a high performance dual step-down
switching regulator controller that drives all N-channel
synchronous power MOSFET stages. A constant frequency
current mode architecture allows a phase-lockable fre-
quency of up to 850kHz. Power loss and noise due to the
input capacitor ESR are minimized by operating the two
controller outputs out of phase.
The 170μA no-load quiescent current extends operating
life in battery powered systems. OPTI-LOOP compensation
allows the transient response to be optimized over a wide
range of output capacitance and ESR values. The LTC3868-
1 features a precision 0.8V reference and a power good
output indicator. A wide 4V to 24V input supply range
encompasses a wide range of intermediate bus voltages
and battery chemistries.
Independent soft-start pins for each controller ramp the
output voltages during start-up. Current foldback limits
MOSFET heat dissipation during short-circuit conditions.
The output short-circuit latchoff feature further protects
the circuit in short-circuit conditions.
Notebook and Palmtop Computers
Portable Instruments
Battery Operated Digital Devices
Distributed DC Power Systems
APPLICATIONS
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TYPICAL APPLICATION
For a leadless 32-pin QFN package with the additional fea-
tures of adjustable current limit, clock out, phase modula-
tion and two PGOOD outputs, see the LTC3868 data sheet.
L , LT, LTC, LTM, Burst Mode, OPTI-LOOP, μModule, Linear Technology and the Linear logo
are registered trademarks and No R SENSE and UltraFast are trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners. Protected by U.S.
Patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, 6304066, 6580258.
High Ef?ciency Dual 8.5V/3.3V Step-Down Converter
4.7μF
22μF
50V
V IN
9V TO 24V
Ef?ciency and Power Loss
vs Load Current
V IN
INTV CC
100
10000
3.3μH
0.1μF
TG1
BOOST1
TG2
BOOST2
0.1μF
7.2μH
90
80
1000
SW1
SW2
70
BG1
SENSE1 +
LTC3868-1
BG2
PGND
SENSE2 +
60
50
40
EFFICIENCY
POWER LOS S
100
10
0.007Ω
0.01Ω
30
V OUT1
3.3V
5A
62.5k
150μF
680pF
SENSE1 –
V FB1
I TH1
SS1
SGND
SENSE2 –
V FB2
I TH2
SS2
680pF
20k
193k
V OUT2
8.5V
3.5A
150μF
20
10
0
0.0001
0.001
V IN = 12V
V OUT = 3.3V
FIGURE 12 CIRCUIT
0.01 0.1 1 10
1
0.1
20k
15k
0.1μF
0.1μF
15k
OUTPUT CURRENT (A)
38681 TA01b
38681 TA01
38681fd
1
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LTC3868EUH#TRPBF 功能描述:IC REG CTRLR BUCK PWM CM 32-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - DC DC 切换控制器 系列:PolyPhase® 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC3868IGN-1#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:PolyPhase® 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR)
LTC3868IGN-1#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:PolyPhase® 标准包装:2,500 系列:- PWM 型:电流模式 输出数:1 频率 - 最大:500kHz 占空比:96% 电源电压:4 V ~ 36 V 降压:无 升压:是 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:24-WQFN 裸露焊盘 包装:带卷 (TR)
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