Datasheet - ST730 - 300 mA, 28 V low-dropout voltage regulator, with 5 µA quiescent current
Document overview
- Manufacturer or author: STMICROELECTRONICS
- PDF pages: 22
Technical content
Datasheet sections
- 1 Schematic diagram
- 2 Pin configuration
- 3 Typical application
- 4 Maximum ratings
- 5 Electrical characteristics
- 6 Application information
- 6.1 External capacitors
- 6.2 Output voltage adjustment
- 6.3 Power dissipation
- 6.4 Protection features
- 7 Typical performance characteristics
- 8 Package information
- 8.1 SOT23-5L package information
- 8.2 Packing information
- 9 Ordering information
Features
- Wide input voltage range : 2.5 V to 28 V
- Ultra-low quiescent current: typ. 5 μA at no-load, 10 μA max. across full temperature range, 1 μA max. in shutdown
- High output voltage accuracy: ± 0.5% @ 25 °C, ± 2.5% across temperature range
- Output current up to 300 mA
- Fixed output voltage versions, starting from 1.2 V to 12 V with 100 mV step
- Adjustable voltage version, starting from 1.2 V to VIN - VDROP
- Stable with low ESR capacitors (0.47 µF min.)
- Thermal shutdown protection
- Current limit and SOA protection
- -40 °C to +125 °C operating temperature range
Applications
- Post regulation
- Electronic meters
- Smoke detectors / alarms
- Portable equipment
- Industrial application
Description
The ST730 is 300 mA LDO regulator, designed to be used in several medium voltage applications. Ultra-low quiescent current of 5 μA makes it suitable for applications permanently connected to power supply/battery. This feature is also useful when electronic modules remain permanently turned on. The ST730 embeds protection functions, such as: current limit, short-circuit and thermal shutdown. The extended input voltage range, very low drop voltage and low quiescent current features make it suitable also for low power after-market automotive and consumer applications. SOT23-5L Maturity status link ST732 300 mA, 28 V low-dropout voltage regulator, with 5 µA quiescent current ST730 Datasheet DS13036 - Rev 5 - December 2023 For further information contact your local STMicroelectronics sales office.
1 Schematic diagram
Figure 1. Block diagram - Fixed version Figure 2. Block diagram - Adjustable version
2 Pin configuration
Figure 3. Pin connection (top view) Table 1. Pin description
1 VOUT Regulated output voltage
2 GND Ground
3 VIN Input voltage
Enable pin: Low = shutdown, High = active.
3 Typical application
Figure 4. Typical application circuit, fixed version Figure 5. Typical application circuit, adjustable version
4 Maximum ratings
Table 2. Absolute maximum ratings operation under these conditions is not implied. All values are referred to GND. Table 3. Thermal data Note: RthJA based on 4-layer (2S2P) JEDEC test board constructed based on JESD 51-7 specification. Table 4. Electro static discharge
5 Electrical characteristics
TA = TJ = -40 °C to +125 °C, typical values refer to TA = +25 °C, VIN = VEN = VOUT + 1 V (1), IOUT = 10 mA, CIN = 0.1 µF, COUT = 0.47 µF, unless otherwise specified (see note). Table 5. Electrical characteristics for ST730, Fixed version
- VIN = VOUT + 1 V or 2.5 V, whichever is greater.
- The device is able to properly regulate the output voltage with no load.
- Guaranteed by design, not tested in production.
- The current limit is a function of (VIN - VOUT) differential during operation. Maximum available current is limited. Refer to
cycle pulse techniques are used.
Electrical characteristics
TA = TJ = -40 °C to +125 °C, typical values refer to TA = +25 °C, VIN = VEN = 2.5 V, IOUT = 10 mA, CIN = 0.1 µF, COUT = 0.47 µF, unless otherwise specified (see note). Table 6. Electrical characteristics for ST730, Adjustable version
- The device is able to properly regulate the output voltage with no load.
- Guaranteed by design, not tested in production.
- The current limit is a function of (VIN - VOUT) differential during operation. Maximum available current is limited. Refer to
Section 6.4 Protection features for more information. cycle pulse techniques are used.
6 Application information
6.1 External capacitors
The ST730 voltage regulator requires external capacitors to ensure the control loop stability. These capacitors must be selected to meet the requirements of minimum capacitance and equivalent series resistance defined in the following chapters. Input and output capacitors should be located as close as possible to the relevant pins. Input capacitor An input capacitor, whose minimum value is 0.1 μF, must be placed as close as possible to the input in of the device and returned to a clean analog ground. A good quality, low-ESR ceramic capacitor is suggested. It helps to ensure stability of the control loop, reduces the effects of inductive sources and improves ripple rejection. Values, which are higher than 0.1 μF, are suggested in case of fast load transients in the application. There is no maximum limit to the input capacitance. Output capacitor The ST730 requires a capacitor connected on its output, to keep the control loop stable and reduce the risk of ringing and oscillations. The control loop is designed to be stable with any good quality ceramic capacitor (such as X5R/X7R types) with a minimum value of 0.47 μF and equivalent series resistance in the [5 – 500 mΩ] range. It is important to highlight that the output capacitor must maintain its capacitance and ESR in the stable region over the full operating temperature, load and input voltage ranges, to assure stability. Therefore, capacitance and ESR variations must be taken into account in the design phase to ensure the device works in the expected stability region. There is no maximum limit to the output capacitance, provided that the above conditions are satisfied.
6.2 Output voltage adjustment
In the adjustable version the output voltage can be adjusted to any voltage, starting from 1.2 V (VADJ) up to the input voltage minus the voltage drop (VDROP) across the internal power pass element, by connecting a resistor divider between the ADJ pin and the output, allowing the remote voltage sensing. The resistor divider should be selected using the following equation: V OU T = V AD J 1 + R 1 / R 2 (1) with VADJ = 1.2 V (typ.) and VOUT < VIN - VDROP(MAX) For best accuracy and stability the resistor divider should be designed in order to allow that a current of at least 500 nA flows across it. The current flowing into the ADJ pin is typically less than 10 nA, therefore it causes negligible change in the final output voltage.
6.3 Power dissipation
A proper PCB design is recommended, to ensure that the device internal junction temperature is kept below 125 °C, in all the operating condition. The thermal energy generated by the device flows from the die surface to the PCB copper area through the package leads. The PCB copper area acts as a heat sink. The footprint copper pads should be as wider as possible to spread and dissipate the heat to the surrounding environment. Thermal micro-vias to the inner or backside copper layers improve the overall thermal performance of the device. The power dissipation of the LDO depends on the input voltage, output voltage and output current, and is given by: P D = V I N − V OU T I OU T (2) The junction temperature of the device is: T J _ M A X = T A + R t ℎ J A × P D (3) where: TJ_MAX is the maximum junction of the die,125 °C; TA is the ambient temperature; RthJA is the thermal resistance junction-to-ambient. With the above equation it is possible to calculate the maximum allowable power dissipation, therefore the maximum load current for a certain voltage drop. Appropriate de-rating of the operating condition can be applied accordingly. ST730
Application information
6.4 Protection features
Due to the wide input voltage range, high power dissipation could occur in case of damaged/shorted load. For this reason the ST730 embeds a SOA protection-current limit circuit, which acts in case of overload or short-circuit on the output, clamping the load current to a safe value. The current limit value is purposely made depended on the voltage drop (VIN - VOUT), so that the maximum dissipated power is always kept under control. The non-constant current limit characteristic shown in Figure 18. Short circuit current vs. dropout voltage should be taken into account to calculate the maximum load current the device can supply for a certain dropout voltage. Normal operation is restored if the overload disappears, but prolonged operation in current limit may lead to high power dissipation inside the LDO and subsequently to thermal shutdown. Thermal protection An internal thermal feedback loop disables the output voltage if the die temperature reaches approximately 160 °C. This feature protects the device from excessive temperature that could lead to permanent damage to the LDO. Once the thermal protection is triggered and the device is shut down, normal operation is automatically recovered if the die temperature falls below 140 °C (thermal protection hysteresis of 20 °C typically). Continuous operation above the maximum ratings may lead to permanent damage to the device. In case of operation with strongly inductive loads, undershoots on the output may happen. If those negative spikes overcome the absolute maximum ratings of the device, permanent damage may occur. A schottky diode connected in parallel to the output port reduces the risk of damages in such operating cases. ST730
7 Typical performance characteristics
CIN = COUT = 1 μF, VIN = 2.5 V, VOUT = VADJ, TJ = 25 °C, unless otherwise specified. Figure 6. Reference voltage vs. temperature, no load Figure 7. Reference voltage vs. load current and Figure 8. Output voltage vs. temperature Figure 9. Output voltage vs. temperature (IOUT = 300 mA)
8 Package information
In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK packages, depending on their level of environmental compliance. ECOPACK specifications, grade definitions and product status are available at: www.st.com. ECOPACK is an ST trademark.
8.1 SOT23-5L package information
Figure 26. SOT23-5L package outline Table 7. SOT23-5L package mechanical data
Package information
DS13036 - Rev 5 page 14/22
Figure 27. SOT23-5L recommended footprint DS13036 - Rev 5 page 15/22
8.2 Packing information
Figure 28. SOT23-5L tape and reel drawing Table 8. SOT23-5L tape and reel mechanical data DS13036 - Rev 5 page 16/22
9 Ordering information
Table 9. Order code Note: Other voltage options can be available on request. Contact local sales office.
Ordering information
DS13036 - Rev 5 page 17/22
Revision history
Table 10. Document revision history 17-Jun-2019 1 Initial release. 18-Feb-2020 2 Updated VOUT, ΔVOUT values in Table 5 and VADJ values in Table 6. 15-Jun-2020 3 Added new order codes in Order code.
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