ST715XX STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 19
Technical content
Datasheet sections
- 1 Diagram
- 2 Pin configuration
- 3 Maximum ratings
- 4 Electrical characteristics
- 5 Output voltage selection for adj ustable version
- 5.1 External capacitor requirements
- 5.2 Power dissipation and junction temperature
- 6 Typical application
- 7 Typical performance characteristi cs
- 8 Package mechanical data
- 9 Revision history
Features
■ 2.5 V to 24 V input voltage ■ Low dropout voltage (500 mV typ. at 85 mA) ■ Very low quiescent current (3.8 µA typ. at full load) ■ 85 mA guaranteed output current ■ Output voltage: fixed or adjustable ■ Compatible with ceramic output capacitors from 0.47 µF to 10 µF ■ Internal current limit ■ Package DFN8 (3 x 3 mm), SOT23-5L ■ Temperature range: -40 °C to 125 °C
Applications
■ Mobile phones ■ Personal digital assistant (PDAs) ■ Cordless phones and similar battery powered systems
Description
The ST715xx is a high voltage, ultra low quiescent low drop linear regulator capable of providing an output current in excess of 85 mA. The device operates over an input voltage range spanning from 2.5 V to 24 V, and is also stable with output ceramic capacitors. Fault condition protection includes short-circuit current limitation. The ultra low quiescent current of 3.8 µA at full load makes it highly suitable for low power applications and battery powered systems. The wide input voltage range makes the ST715xx an ideal solution for low power industrial applications also. The ST715xx is available in the DFN8 (3 x 3 mm) 8 leads or the SOT23-5. DFN8 (3 x 3 mm)SOT23-5L Table 1. Device summary
1 Diagram
Figure 1. Block diagram
2 Pin configuration
Figure 2. Pin connections (top view) Table 2. Pin description (DFN8 3x3 mm) Table 3. Pin description (SOT23-5L)
3 Maximum ratings
Note: Absolute maximum ratings are the values beyond which damage to the device may occur. Functional operation under these conditions is not implied. Table 4. Absolute maximum ratings Table 5. Thermal data
4 Electrical characteristics
Table 6. Electrical characteristics - adjustable version
- Turn-on time is time measured between the input just exceeding 90% of its final value and the output voltage just reaching
Table 7. Electrical characteristics - fixed version
- Dropout voltage is the input-to-output voltage difference at wh ich the output voltage is 100 mV below its nominal value. This
specification does not apply for output voltages below 2 V.
- Turn-on time is time measured between the input just exc eeding 90 % of its final value and the output voltage just reaching
Output voltage selection for adjustable version ST715XX, ST715XX25, ST715XX33 8/19 Doc ID 14414 Rev 7
5 Output voltage selection for adjustable version
The ST715xx features an adjustable output voltage using two external resistors connected as a voltage divider to the FB pin as shown in the typical application circuit Figure 4. The output voltage is set using the following equation: Equation 1 VOUT = VFB (1 + R1/R2) where typically VFB = 1.2 V. Choose R2 ≥ 5 kΩ in order to optimize quiescent current, accuracy, and high-frequency power-supply rejection. To simplify resistor selection use the following equation: Equation 2 R 1 = R2 x (VOUT/VFB - 1)
5.1 External capacitor requirements
A 0.1 µF or larger input bypass capacitor, connected between IN and GND and located close to the device, is recommended to improve transient response and noise rejection of the power supply as a whole. A higher-value input capacitor may be necessary if large, fast- rise-time load transients will be present in the application and if the device is located several inches away from the power source. The ST715xx requires an output capacitor connected between OUT and GND to stabilize the internal control loop. Any capacitor (including ceramic and tantalum) with a value higher than 0.47 µF will properly stabilize this loop.
5.2 Power dissipation and junction temperature
To ensure reliable operation, worst-case junction temperature should not exceed 125 °C. This restriction limits the power dissipation the regulator can handle in any given application. To ensure that the junction temperature is within acceptable limits, calculate the maximum allowable dissipation, P D(max), and the actual dissipation, PD, which must be less than or equal to PD(max). The maximum power dissipation limit is determined using the following equation: Equation 3 PD(max) = (TJMAX - TA) / RthJA where: T JMAX is the maximum allowable junction temperature. RthJA is the thermal resistance junction-to-ambient for the package. TA is the ambient temperature.
ST715XX, ST715XX25, ST715XX33 Output voltage selection for adjustable version Doc ID 14414 Rev 7 9/19 The regulator dissipation is calculated using the following equation: Equation 4 PD = (VIN - VOUT) x IOUT Power dissipation resulting from quiescent current is negligible. The ST715xx features internal current limiting. During normal operation, it limits output current to approximately 350 mA. When current limiting engages, the output voltage scales back linearly until the overcurrent condition ends. Take care not to exceed the power dissipation ratings of the package.
6 Typical application
Figure 3. Application ci rcuit for fixed version Figure 4. Application circuit for adjustable version
7 Typical performance characteristics
Figure 5. Output voltage vs. temperature Figure 6. Output voltage vs. input voltage Figure 7. Dropout voltage vs. output current Figure 8. C OUT stability region Figure 9. Supply voltage rejection vs. Figure 10. Output noise voltage vs. frequency
8 Package mechanical data
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.
Dim. mm. mil s. A0 . 90 1.45 35.4 57.1 A1 0.00 0.10 0.0 3.9 A2 0. 901 . 30 35.4 51.2 b 0.35 0.50 1 3.7 1 9.7 C0 . 0 9 0.20 3.5 7. 8 D2 . 80 3.00 110.2 11 8.1 E 1.50 1.75 5 9.0 6 8.8 e0 . 95 37.4 H 2.60 3.00 102. 3 118.1 L 0.10 0.60 3.9 23.6 SOT23-5L mechanical data 7049676D
Dim. mm. mil s. A1 0.02 0.05 0. 8 2.0 A3 0.20 7. 9 D2 1.60 3 1.753 1.853 63.1 6 9 73 e 0.65 25.6 DFN8 (3x3 mm) mechanical data
Dim. mm. inch. A1 80 7.0 86 D 20.2 0.7 95 N6 0 2 . 362 T 14.4 0.567 Tape & reel SOT23-xL mechanical data
Dim. mm. inch. A1 80 7.0 87 C 12. 8 13.2 0.504 0.51 9 D 20.2 0.7 95 N6 0 2 . 362 T 14.4 0.567 Ao 3.3 0.130 Bo 3.3 0.130 Ko 1.1 0.04 3 Po 4 0.157 P 8 0.315 Tape & reel QFNxx/DFNxx (3x3) mechanical data
9 Revision history
Table 8. Document revision history 08-Feb-2008 1 Initial release. 19-Feb-2008 2 Modified: Features on page 1. 22-Sep-2008 3 Modifi ed: DFN8 (3x3 mm) mechanical data on page 15. 26-Nov-2008 4 Modified: Section 5 on page 8. 24-Mar-2010 5 Modified: Table 4 on page 5. 20-May-2010 6 Modified: I Q max values Table 6 on page 6 and Table 7 on page 7. 24-Jun-2010 7 Modified: Table 2 and Table 3 on page 4.