L5970D_07 STMICROELECTRONICS | Alldatasheet
Document overview
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- PDF pages: 16
Technical content
Datasheet sections
- 1 Pin settings
- 1.1 Pin connection
- 1.2 Pin description
- 2 Electrical data
- 2.1 Maximum ratings
- 2.2 Thermal data
- 3 Electrical characteristics
- 4 Typical characteristics
- 5 Application circuit
- 6 Application ideas
- 7 Package mechanical data
- 8 Order code
- 9 Revision history
Up to 1A step down switching regulator General features ■ Up to 1A output current ■ Operating input voltage from 4.4V to 36V ■ 3.3V / (±2%) reference voltage ■ Output voltage adjustable from 1.2V to 35V ■ Low dropout operation: 100% duty cycle ■ 250KHz Internally fixed frequency ■ Voltage feedforward ■ Zero load current operation ■ Internal current limiting ■ Inhibit for zero current consumption ■ Synchronization ■ Protection against feedback disconnection ■ Thermal shutdown
Applications
■ Consumer: STB, DVD, TV, VCR, car radio, LCD monitors ■ Networking: XDSL, modems, DC-DC modules ■ Computer: printers, audio/graphic cards, optical storage, hard disk drive ■ Industrial: changers, car battery, DC-DC converters
Description
The L5970D is a step down monolithic power switching regulator capable to deliver up to 1A at output voltages from 1.2V to 35V. The device uses an internal P-Channel D-MOS transistor (with a typical Rdson of 250mΩ) as switching element to minimize the size of the external components. An internal oscillator fixes the switching frequency at 250KHz. Having a minimum input voltage of 4.4V only, it is particularly suitable for 5V bus, available in all computer related applications. Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection. SO8 Test application circuit D98IN954C L5970D 10µF 35V CERAMIC 100µF 10V VOUT=3.3V VIN = 4.4V to 35V 5.6K 3.3KR3 4.7K 22nF 220pF STPS2L40U 3.3V INH. SYNC. COMP VCC VREF OUT FB GND L1 33µH
1 Pin settings
1.1 Pin connection
Figure 1. Pin connection (top view)
1.2 Pin description
Table 1. Pin description 2 SYNC Master/slave synchronization. 4 COMP E/A output for frequency compensation. REF. No cap is requested for stability. 8 VCC Unregulated DC input voltage.
2 Electrical data
2.1 Maximum ratings
2.2 Thermal data
Table 2. Absolute maximum ratings I1 Maximum output current int. limit. Table 3. Thermal data
3 Electrical characteristics
Table 4. Electrical characteristics ( TJ = 25°C, VCC = 12V, unless otherwise specified) Dynamic characteristics (see test circuit ).
- Specification Referred to T J from -40 to 125°C. Specification over the -40 to +125 TJ Temperature range
are assured by design, characterization and statistical correlation.
4 Typical characteristics
Figure 2. Junction temperature vs. Figure 3. Load regulator Figure 4. Junction temperature vs. Figure 5. Line regulator Figure 6. Junction temperature vs. Figure 7. Output voltage vs. junction
5 Application circuit
Figure 13. Demo board application circuit Table 5. Component list
6 Application ideas
Figure 17. Dual output voltage with auxiliary winding Figure 18. Buck-boost regulator Figure 19. Positive Buck-Boost regulator Figure 20. Synchronization example
Package mechanical data L5970D
7 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK® packages. These packages have a Lead-free second level interconnect . The category of second level interconnect is marked on the package and on the inner box label, in compliance with JEDEC Standard JESD97. The maximum ratings related to soldering conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com
Table 6. MSOP8 Mechanical data
- D and F does not include mold flash or protrusions . Mold flash or potrusions shall not exceed 0.15mm
Figure 21. Package dimensions
8 Order code
Table 7. Order code
9 Revision history
Table 8. Revision history