Datasheet LT1129, LT1129-3.3, LT1129-5 (Analog Devices) - 9
| Fabricante | Analog Devices |
| Descripción | Micropower Low Dropout Regulators with Shutdown |
| Páginas / Página | 16 / 9 — PIN FUNCTIONS. Input Pin:. Sense Pin:. Output Pin:. Adjust Pin:. Shutdown … |
| Formato / tamaño de archivo | PDF / 181 Kb |
| Idioma del documento | Inglés |
PIN FUNCTIONS. Input Pin:. Sense Pin:. Output Pin:. Adjust Pin:. Shutdown Pin (. Figure 1. Kelvin Sense Connection
Línea de modelo para esta hoja de datos
- LT1129CQ#PBF LT1129CQ#PBF LT1129CQ#TRPBF LT1129CQ#TRPBF LT1129CQ-3.3#PBF LT1129CQ-3.3#PBF LT1129CQ-3.3#TRPBF LT1129CQ-3.3#TRPBF LT1129CQ-5#PBF LT1129CQ-5#PBF LT1129CQ-5#TRPBF LT1129CQ-5#TRPBF LT1129CS8#PBF LT1129CS8#PBF LT1129CS8#TRPBF LT1129CS8#TRPBF LT1129CS8-3.3#PBF LT1129CS8-3.3#PBF LT1129CS8-3.3#TRPBF LT1129CS8-3.3#TRPBF LT1129CS8-5#PBF LT1129CS8-5#PBF LT1129CS8-5#TRPBF LT1129CS8-5#TRPBF LT1129CST-3.3#PBF LT1129CST-3.3#PBF LT1129CST-3.3#TRPBF LT1129CST-3.3#TRPBF LT1129CST-5#PBF LT1129CST-5#PBF LT1129CST-5#TRPBF LT1129CST-5#TRPBF LT1129CT#PBF LT1129CT#PBF LT1129CT-3.3#06PBF LT1129CT-3.3#06PBF LT1129CT-3.3#PBF LT1129CT-3.3#PBF LT1129CT-5#06PBF LT1129CT-5#06PBF LT1129CT-5#PBF LT1129CT-5#PBF LT1129IQ#PBF LT1129IQ#PBF LT1129IQ#TRPBF LT1129IQ#TRPBF LT1129IQ-3.3#PBF LT1129IQ-3.3#PBF LT1129IQ-3.3#TRPBF LT1129IQ-3.3#TRPBF LT1129IQ-5#PBF LT1129IQ-5#PBF LT1129IQ-5#TRPBF LT1129IQ-5#TRPBF LT1129IS8#PBF LT1129IS8#PBF LT1129IS8#TRPBF LT1129IS8#TRPBF LT1129IS8-3.3#PBF LT1129IS8-3.3#PBF LT1129IS8-3.3#TRPBF LT1129IS8-3.3#TRPBF LT1129IS8-5#PBF LT1129IS8-5#PBF LT1129IS8-5#TRPBF LT1129IS8-5#TRPBF LT1129IST-3.3#PBF LT1129IST-3.3#PBF LT1129IST-3.3#TRPBF LT1129IST-3.3#TRPBF LT1129IST-5#PBF LT1129IST-5#PBF LT1129IST-5#TRPBF LT1129IST-5#TRPBF LT1129IT#06PBF LT1129IT#06PBF LT1129IT#PBF LT1129IT#PBF LT1129IT-3.3#PBF LT1129IT-3.3#PBF LT1129IT-5#06PBF LT1129IT-5#06PBF LT1129IT-5#PBF LT1129IT-5#PBF LT1129MPST-3.3 LT1129MPST-3.3#PBF LT1129MPST-3.3#PBF LT1129MPST-3.3#TR LT1129MPST-3.3#TRPBF LT1129MPST-3.3#TRPBF
Versión de texto del documento
LT1129/LT1129-3.3/LT1129-5
PIN FUNCTIONS Input Pin:
Power is supplied to the device through the used it can be left open circuit. The device will be active, input pin. The input pin should be bypassed to ground output on, if the shutdown pin is not connected. if the device is more than 6 inches away from the main
Sense Pin:
For fi xed voltage versions of the LT1129 input fi lter capacitor. In general, the output impedance of (LT1129-3.3, LT1129-5) the sense pin is the input to the a battery rises with frequency so it is advisable to include error amplifi er. Optimum regulation will be obtained at the a bypass capacitor in battery-powered circuits. A bypass point where the sense pin is connected to the output pin. capacitor in the range of 1μF to 10μF is suffi cient. The For most applications the sense pin is connected directly LT1129 is designed to withstand reverse voltages on the to the output pin at the regulator. In critical applications input pin with respect to both ground and the output pin. small voltage drops caused by the resistance (R In the case of a reversed input, which can happen if a P) of PC traces between the regulator and the load, which would battery is plugged in backwards, the LT1129 will act as if normally degrade regulation, may be eliminated by con- there is a diode in series with its input. There will be no necting the sense pin to the output pin at the load as reverse current fl ow into the LT1129 and no reverse volt- shown in Figure 1 (Kelvin Sense Connection). Note that age will appear at the load. The device will protect both the voltage drop across the external PC traces will add to itself and the load. the dropout voltage of the regulator. The sense pin bias
Output Pin:
The output pin supplies power to the load. An current is 15μA at the nominal regulated output voltage. output capacitor is required to prevent oscillations. See This pin is internally clamped to –0.6V (one VBE). the Applications Information section for recommended
Adjust Pin:
For the LT1129 (adjustable version) the adjust value of output capacitance and information on reverse pin is the input to the error amplifi er. This pin is internally output characteristics. clamped to 6V and –0.6V (one VBE). This pin has a bias
Shutdown Pin (
SHDN
):
This pin is used to put the device current of 150nA which fl ows into the pin. See Bias Cur- into shutdown. In shutdown the output of the device is rent curve in the Typical Performance Characteristics. The turned off. This pin is active low. The device will be shut adjust pin reference voltage is equal to 3.75V referenced down if the shutdown pin is actively pulled low. The to ground. shutdown pin current with the pin pulled to ground will be 6μA. The shutdown pin is internally clamped to 7V RP and – 0.6V (one V IN OUT BE). This allows the shutdown pin to be driven directly by 5V logic or by open collector logic with LT1129 1μF a pull-up resistor. The pull-up resistor is only required SHDN SENSE LOAD + to supply the leakage current of the open collector gate, 10μF GND normally several microamperes. Pull-up current must be limited to a maximum of 20mA. A curve of shutdown pin RP 112935 F01 input current as a function of voltage appears in the Typical Performance Characteristics. If the shutdown pin is not
Figure 1. Kelvin Sense Connection APPLICATIONS INFORMATION
The LT1129 is a micropower low dropout regulator with features which make it ideal for use in battery-powered shutdown, capable of supplying 700mA of output current systems. The device is protected against reverse input at a dropout voltage of 0.4V. The device operates with very voltages. In battery backup applications where the output low quiescent current (50μA). In shutdown the quiescent can be held up by a backup battery when the input is pulled current drops to only 16μA. In addition to the low quies- to ground, the LT1129 acts like it has a diode in series cent current the LT1129 incorporates several protection with its output and prevents reverse current fl ow. 112935ff 9
PIN FUNCTIONS Input Pin:
Power is supplied to the device through the used it can be left open circuit. The device will be active, input pin. The input pin should be bypassed to ground output on, if the shutdown pin is not connected. if the device is more than 6 inches away from the main
Sense Pin:
For fi xed voltage versions of the LT1129 input fi lter capacitor. In general, the output impedance of (LT1129-3.3, LT1129-5) the sense pin is the input to the a battery rises with frequency so it is advisable to include error amplifi er. Optimum regulation will be obtained at the a bypass capacitor in battery-powered circuits. A bypass point where the sense pin is connected to the output pin. capacitor in the range of 1μF to 10μF is suffi cient. The For most applications the sense pin is connected directly LT1129 is designed to withstand reverse voltages on the to the output pin at the regulator. In critical applications input pin with respect to both ground and the output pin. small voltage drops caused by the resistance (R In the case of a reversed input, which can happen if a P) of PC traces between the regulator and the load, which would battery is plugged in backwards, the LT1129 will act as if normally degrade regulation, may be eliminated by con- there is a diode in series with its input. There will be no necting the sense pin to the output pin at the load as reverse current fl ow into the LT1129 and no reverse volt- shown in Figure 1 (Kelvin Sense Connection). Note that age will appear at the load. The device will protect both the voltage drop across the external PC traces will add to itself and the load. the dropout voltage of the regulator. The sense pin bias
Output Pin:
The output pin supplies power to the load. An current is 15μA at the nominal regulated output voltage. output capacitor is required to prevent oscillations. See This pin is internally clamped to –0.6V (one VBE). the Applications Information section for recommended
Adjust Pin:
For the LT1129 (adjustable version) the adjust value of output capacitance and information on reverse pin is the input to the error amplifi er. This pin is internally output characteristics. clamped to 6V and –0.6V (one VBE). This pin has a bias
Shutdown Pin (
SHDN
):
This pin is used to put the device current of 150nA which fl ows into the pin. See Bias Cur- into shutdown. In shutdown the output of the device is rent curve in the Typical Performance Characteristics. The turned off. This pin is active low. The device will be shut adjust pin reference voltage is equal to 3.75V referenced down if the shutdown pin is actively pulled low. The to ground. shutdown pin current with the pin pulled to ground will be 6μA. The shutdown pin is internally clamped to 7V RP and – 0.6V (one V IN OUT BE). This allows the shutdown pin to be driven directly by 5V logic or by open collector logic with LT1129 1μF a pull-up resistor. The pull-up resistor is only required SHDN SENSE LOAD + to supply the leakage current of the open collector gate, 10μF GND normally several microamperes. Pull-up current must be limited to a maximum of 20mA. A curve of shutdown pin RP 112935 F01 input current as a function of voltage appears in the Typical Performance Characteristics. If the shutdown pin is not
Figure 1. Kelvin Sense Connection APPLICATIONS INFORMATION
The LT1129 is a micropower low dropout regulator with features which make it ideal for use in battery-powered shutdown, capable of supplying 700mA of output current systems. The device is protected against reverse input at a dropout voltage of 0.4V. The device operates with very voltages. In battery backup applications where the output low quiescent current (50μA). In shutdown the quiescent can be held up by a backup battery when the input is pulled current drops to only 16μA. In addition to the low quies- to ground, the LT1129 acts like it has a diode in series cent current the LT1129 incorporates several protection with its output and prevents reverse current fl ow. 112935ff 9