By STMicroelectronics 101
The LD1117S33TR is a low dropout linear voltage regulator commonly used in power management applications to provide stable output voltage.
LD1117S33TR is a low dropout voltage regulator that provides up to 800 mA current output. The SOT-223 package optimizes its thermal performance while saving space. High operating efficiency is ensured through the NPN bypass transistor. Unlike PNP mode, this In this mode, most of the quiescent current flows to the load.
Ⅰ.Pin layout of LD1117S33TR
The pin layout diagram is as follows:
LD1117S33TR is a three-pin linear voltage regulator:
1.Input: This is the input power pin of the voltage regulator. You will input your power supply voltage to be regulated to this pin.
2.Ground: This pin is the ground pin and is used to connect to the power ground.
3.Output: This is the output voltage pin of the voltage regulator, which will provide a stable 3.3V output voltage.
Ⅱ.Features of LD1117S33TR
•Low dropout voltage (1 V typ.)
•Low dropout: refers to a situation where a circuit can still operate normally and the output is stable when the input voltage is slightly higher than 3.3V. When the input voltage is slightly lower than 3.3V, the output will change greatly
•2.85 V device performances are suitable for SCSI-2 active termination
•Output current up to 800 mA
•Low power consumption: LD1117S33TR consumes very little power in standby and light load conditions, which can effectively extend battery life and reduce energy consumption.
•Fixed output voltage of: 1.2 V, 1.8 V, 2.5 V, 3.3 V, 5.0 V
•Thermal stability: LD1117S33TR has good thermal stability and can provide stable performance under a certain range of temperature conditions.
•Adjustable version availability (VREF = 1.25 V)
•Internal current and thermal limit
•Short circuit protection: LD1117S33TR usually has built-in short circuit protection function to avoid damage when the output is short circuited
•Available in ± 1 % (at 25 °C) and 2 % in full temperature range
•Supply voltage rejection: 75 dB (typ.)
•Overheating protection: LD1117S33TR usually has an overheating protection feature, which allows LD1117S33TR to automatically shut down when the operating temperature exceeds its nominal temperature. This helps protect equipment from overheating damage
Ⅲ.Specification parameters of LD1117S33TR
•Operating voltage: 0V ~ 15V
•Number of output interfaces: 1
•Input voltage (DC): 10.0V (max)
•Output voltage:Output voltage:
•Output current: 950 mA
•Quiet current: 5 mA
•Input voltage (minimum): 3.3 V
•Input voltage (maximum): 15 V
•Minimum operating temperature: 0 C
•Maximum operating temperature: + 125 C
•Packaging: Tape & Reel (TR)
•Fallback voltage—maximum: 1.1 V
•Ib - Input bias current: 5 mA
•Line regulation: 6 mV
•Load regulation: 10 mV
•Power dissipation: 12 W
•Supply current: 10 mA
Ⅳ.Application of LD1117S33TR
1.Embedded systems: LD1117S33TR is often used in embedded systems, such as microcontrollers, single-board computers, sensor nodes, etc., to provide the stable 3.3V power supply required by these systems.
2.Sensor: In many sensor applications, LD1117S33TR is used to provide the constant power supply voltage required by the sensor to ensure the accuracy of sensor measurements.
3.Embedded controller: In embedded controller and microprocessor applications, LD1117S33TR is used to provide stable power supply to these controllers to ensure their stability and reliability.
4.Electronic equipment: It is widely used in various electronic equipment, such as consumer electronics, communication equipment, audio equipment, displays, etc., to ensure the stability of the power supply voltage of these equipment.
5.Medical equipment: Due to its high reliability and stability, LD1117S33TR is often used in medical equipment, such as medical monitoring equipment, medical sensors, etc.
6.Communication equipment: LD1117S33TR can be used in wireless communication equipment, routers, switches, etc. to provide stable power supply voltage.
7.Battery-powered equipment: Due to its low power consumption characteristics, LD1117S33TR is often used in battery-powered equipment, helping to extend battery life.
Ⅴ.Package type of LD1117S33TR
1.SOT-223 package: It is a surface mount package with three pins. It is a surface mount package with a compact circuit board design and is widely used in various electronic applications.
2.TO-220 package: TO-220 is a larger pin package suitable for applications with higher heat dissipation requirements. It usually has three pins, one of which is a metal shell for heat dissipation.
3.DPAK package: TO-252 is a surface mount package, usually with three pins. It is smaller than the TO-220 package but equally suitable for some degree of heat dissipation.
4.SO-8 package: usually has eight pins. The physical size of the SO-8 package is relatively small, making it suitable for compact circuit board designs. It is usually rectangular in shape with pins running along two opposite sides. : SO-8 package is widely used in various integrated circuits, including op amps, comparators, voltage regulators, power management devices, amplifiers, etc.
Ⅵ.Performance of LD1117S33TR in different temperature ranges
The LD1117S33TR is a linear regulator (LDO) whose performance may vary somewhat over different temperature ranges, but generally maintains relatively stable performance within the specified operating temperature range.
1.Operating temperature range: The manufacturer usually specifies the operating temperature range of the LD1117S33TR in the product's specification sheet or data sheet. Within the specified temperature range, the LD1117S33TR is generally able to provide stable output voltage and current.
2.Thermal dissipation: The heat dissipation performance of the LD1117S33TR package will also affect its stable performance in high temperature environments. In a high-temperature environment, without appropriate heat dissipation measures, the LD1117S33TR may cause device performance degradation due to overheating, and may even become unstable. Therefore, it is necessary to limit the output current when designing the circuit to avoid device performance degradation due to overheating.
3.Temperature drift: The output voltage of a linear regulator usually changes to a certain extent as the temperature changes. To illustrate the range of changes in output voltage at different temperatures, manufacturers provide specifications for temperature drift in the data sheet.
Ⅶ.Alternate model of LD1117S33TR
Frequently Asked Questions
1. Does the LD1117S33TR require a heat sink during continuous operation?
If the input voltage is much higher than 3.3V (stable output voltage) and the output current is large, a large power consumption difference will occur. This will cause the regulator to generate more heat, so a heat sink may be needed to dissipate the heat. Ambient temperature is also a factor in considering whether a heat sink is needed. In high temperature environments, the regulator may overheat more easily, so a heat sink may be required.
2. What is the efficiency of LD1117S33TR?
For LD1117S33TR, when the voltage difference between Vin and the output voltage (3.3V) is larger, the efficiency is lower. For example, if the input voltage is 5V, then the voltage difference is 5V - 3.3V = 1.7V, so most of the voltage difference will be converted into heat rather than useful output power. This results in lower efficiency.
3.What are the load adjustment characteristics of LD1117S33TR?
The load regulation characteristic of LD1117S33TR refers to the change of its output voltage under different load conditions. Generally, linear voltage regulators have better load regulation characteristics under different loads, and the changes in output voltage are small.