参数资料
| 型号： | LTC3035EDDB#TRPBF |
| 厂商： | Linear Technology |
| 文件页数： | 6/12页 |
| 文件大小： | 0K |
| 描述： | IC REG LDO ADJ .3A 8-DFN |
| 产品培训模块： | More Information on LDOs |
| 标准包装： | 2,500 |
| 稳压器拓扑结构： | 正，可调式 |
| 输出电压： | 0.4 V ~ 3.6 V |
| 输入电压： | 1.7 V ~ 5.5 V |
| 电压 - 压降（标准）： | 0.045V @ 300mA |
| 稳压器数量： | 1 |
| 电流 - 输出： | 300mA（最小） |
| 工作温度： | -40°C ~ 125°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 8-WFDFN 裸露焊盘 |
| 供应商设备封装： | 8-DFN（3x2） |
| 包装： | 带卷 (TR) |
LTC3035
APPLICATIO S I FOR ATIO
(Refer to Block Diagram)
The LTC3035 is a VLDO (very low dropout) linear regulator
which operates from input voltages between 1.7V and
5.5V. The LDO uses an internal NMOS transistor as the
pass device in a source-follower configuration. The inter-
nal charge pump generator provides the high supply
necessary for the LDO circuitry while the output current
5
3.23
1.9 ? V IN
comes directly from the IN input for high efficiency
regulation.
1.7
2.63
V IN (V)
5.5
3035 F01
Charge Pump Operation
The LTC3035 contains a charge pump to produce the
necessary bias voltage supply for the LDO. The charge
pump utilizes Burst Mode operation to achieve high
efficiency for the relatively low current levels needed for
the LDO circuitry. The charge pump requires only a small
0.1 μ F flying capacitor between the CP and CM pins and a
1 μ F bypass capacitor at BIAS.
An internal oscillator centered at 800kHz controls the
two-phase switching cycle of the charge pump. During the
first phase a current source charges the flying capacitor
between V IN and GND. During the second phase, the
capacitor’s positive terminal connects to BIAS and the
current source drives the capacitor’s minus terminal,
delivering charge to the BIAS bypass capacitor and in-
creasing its voltage.
A burst comparator with hysteresis monitors the voltage
on the BIAS pin. When BIAS is above the upper threshold
of the comparator, the oscillator is disabled and no switch-
ing occurs. When BIAS falls below the comparator’s lower
threshold, the oscillator is enabled and the BIAS pin gets
charged. The thresholds of the burst comparator are
dynamically adjusted to maintain a DC level shown by
Figure 1. BIAS regulates to 1.9 ? V IN or 5V, whichever
voltage is lower. The voltage ripple at BIAS is controlled to
approximately 1% of its DC value.
LDO Operation
An undervoltage lockout comparator (UVLO) senses the
BIAS voltage to ensure that the BIAS supply for the LDO is
greater than 90% of its regulation value before
enabling the LDO. Once the LDO gets enabled, the UVLO
threshold switches to 50% of its regulation value. Thus the
Figure 1. LTC3035 BIAS Voltage vs V IN Voltage
before the LDO disables. When the LDO is disabled, OUT
is pulled to GND through the external divider and an
internal 2.5k resistor.
The LDO provides a high accuracy output capable of
supplying 300mA of output current with a typical dropout
voltage of only 45mV. A single ceramic capacitor as small
as 1 μ F is all that is required for output bypassing. The low
reference voltage allows the LTC3035 output to be
programmed from 0.4V to 3.6V.
As shown in the Block Diagram, the charge pump output
at BIAS supplies the LDO circuitry while the output current
comes directly from the IN input for high efficiency
regulation. The low quiescent supply current, I IN = 100 μ A,
drops to I IN = 1 μ A typical in shutdown making the LTC3035
an ideal choice for use in battery-powered systems.
The device also includes current limit, thermal overload
protection, and reverse output current protection. The fast
transient response of the follower output stage overcomes
the traditional tradeoff between dropout voltage, quies-
cent current and load transient response inherent in most
LDO regulator architectures. The LTC3035 also includes
overshoot detection circuitry which brings the output back
into regulation when going from heavy to light output
loads (see Figure 2).
The LTC3035 also includes a soft-start feature to prevent
excessive current flow during start-up. After the BIAS
voltage reaches regulation, the soft-start circuitry gradu-
ally increases the LDO reference voltage from 0V to 0.4V
over a period of about 600 μ s. There is a short 700 μ s delay
from the time BIAS reaches regulation until the LDO
output starts to rise (see Figure 3).
BIAS voltage must fall below 50% of its regulation voltage
3035f
6
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相关代理商/技术参数 |
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| LTC3100 | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5MHz Synchronous Dual Channel DC/DC Converter and 100mA LDO |
| LTC3100EUD#PBF | 功能描述:IC REG BUCK/BOOST/LINEAR 16-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压（降压）同步（3），线性（LDO）（2） 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
| LTC3100EUD#TRPBF | 功能描述:IC REG BUCK/BOOST/LINEAR 16-QFN RoHS:是 类别:集成电路 (IC) >> PMIC - 稳压器 - 线性 + 切换式 系列:- 标准包装:2,500 系列:- 拓扑:降压（降压）同步（3），线性（LDO）（2） 功能:任何功能 输出数:5 频率 - 开关:300kHz 电压/电流 - 输出 1:控制器 电压/电流 - 输出 2:控制器 电压/电流 - 输出 3:控制器 带 LED 驱动器:无 带监控器:无 带序列发生器:是 电源电压:5.6 V ~ 24 V 工作温度:-40°C ~ 85°C 安装类型:* 封装/外壳:* 供应商设备封装:* 包装:* |
| LTC3100EUD-PBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5MHz Synchronous Dual Channel DC/DC Converter and 100mA LDO |
| LTC3100EUD-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:1.5MHz Synchronous Dual Channel DC/DC Converter and 100mA LDO |
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