L5970D

L5970D 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 SO8 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. 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 Test application circuit 3.3V VIN = 4.4V to 35V VREF VCC SYNC. C1 10µF 35V CERAMIC COMP C4 22nF C3 220pF 6 8 2 4 INH. R3 4.7K 1 OUT L1 33µH D1 STPS2L40U 5 GND FB VOUT=3.3V L5970D 3 7 R1 5.6K C2 100µF 10V R2 3.3K D98IN954C January 2007 Rev 14 1/16 www.st.com 16 Contents L5970D Contents 1 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 1.2 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 2.2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 4 5 6 7 8 9 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Application ideas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Order code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2/16 L5970D Pin settings 1 1.1 Pin settings Pin connection Figure 1. Pin connection (top view) OUT SYNC INH COMP 1 2 3 4 D98IN955 8 7 6 5 VCC GND VREF FB 1.2 Pin description Table 1. Pin description N° 1 2 3 4 5 6 7 8 Type OUT SYNC INH COMP FB VREF GND VCC Regulator output. Master/slave synchronization. A logical signal (active high) disables the device. If INH not used the pin must be grounded. When it is open an internal pull-up disable the device. E/A output for frequency compensation. Feedback input. Connecting directly to this pin results in an output voltage of 1.23V. An external resistive divider is required for higher output voltages. 3.3V VREF. No cap is requested for stability. Ground. Unregulated DC input voltage. Description 3/16 Electrical data L5970D 2 2.1 Electrical data Maximum ratings Table 2. Absolute maximum ratings Symbol V8 V1 I1 V4, V5 V3 V2 PTOT TJ TSTG Input voltage Output DC voltage Output peak voltage at t = 0.1µs Maximum output current Analog pins INH SYNC Power dissipation at TA ≤ 60°C Operating junction temperature range Storage temperature range Parameter Value 40 -1 to 40 -5 to 40 int. limit. 4 -0.3V to VCC -0.3 to 4 0.75 -40 to 150 -55 to 150 V W °C °C V Unit V V V 2.2 Thermal data Table 3. Thermal data Symbol RthJA Parameter Maximum thermal resistance junction-ambient SO8 120 (1) Unit °C/W 1. Package mounted on board 4/16 L5970D Electrical characteristics 3 Electrical characteristics Table 4. Electrical characteristics ( TJ = 25°C, VCC = 12V, unless otherwise specified) Symbol VCC RDS(on) Il fs Parameter Operating input voltage range Mosfet on Resistance Maximum limiting current Switching frequency 225 Duty cycle Dynamic characteristics (see test circuit ). V5 h Voltage feedback Efficiency 4.4V < VCC < 36V, 20mA < IO < 2A VO = 5V, VCC = 12V 1.220 (1) Test condition Vo = 1.235V; Io = 2A (1) Min 4.4 Typ Max 36 Unit V Ω A KHz KHz % (1) 0.250 1.5 1.87 250 250 0.5 2.25 280 275 100 VCC = 4.4V to 36V (1) 212 0 1.235 1.235 90 1.25 1.272 V V % 1.198 DC characteristics Iqop Iq Total operating quiescent current Quiescent current Duty cycle = 0; VFB = 1.5V Vinh > 2.2V Iqst-by Total stand-by quiescent current VCC = 36V; Vinh > 2.2V (1) (1) 3 5 2.5 mA mA µA µA 50 80 100 150 (1) Inhibit INH threshold voltage Error amplfier VOH VOL Io source Io sink High level output voltage Low level output voltage Source output current Sink output current VFB = 1V VFB = 1.5V VCOMP = 1.9V; VFB = 1V VCOMP = 1.9V; VFB = 1.5V 200 300 3.5 0.4 V V µA Device ON Device OFF 2.2 0.8 V V 1 1.5 mA 5/16 Electrical characteristics Table 4. Electrical characteristics ( TJ = 25°C, VCC = 12V, unless otherwise specified) Symbol Ib Parameter Source bias current DC open loop gain gm Transconductance RL = ∞ Icomp = -0.1mA to 0.1mA VCOMP = 1.9V 50 Test condition Min Typ 2.5 65 Max 4 L5970D Unit µA dB 2.3 mS Sync function High input voltage Low input voltage Slave sink current Master output amplitude Output pulse width Reference section Reference voltage IREF = 0 to 5mA VCC = 4.4V to 36V Line regulation Load regulation Short circuit current IREF = 0mA VCC = 4.4V to 36V IREF = 0 to 5mA 10 (1) VCC = 4.4V to 36V VCC = 4.4V to 36V Vsync = 0.74V (2) Vsync = 2.33V Isource = 3mA no load, Vsync = 1.65V 2.5 VREF 0.74 V V mA mA V µs 0.11 0.21 2.75 0.20 3 0.35 0.25 0.45 3.234 3.2 3.3 3.3 3.366 3.399 V V 5 10 mV 8 18 15 30 mV mA 1. Specification Referred to TJ from -40 to 125°C. Specification over the -40 to +125 TJ Temperature range are assured by design, characterization and statistical correlation. 2. Guaranteed by design. 6/16 L5970D Typical characteristics 4 Typical characteristics Figure 2. Tj(°C) Junction temperature vs. output current Figure 3. Vo (V) 3.312 Load regulator 130 120 110 100 90 80 70 60 50 40 30 20 0.2 Vo=3.3V Vo=2.5V 3.308 3.304 3.3 3.296 3.292 3.288 3.284 3.28 3.276 Vcc = 12V Vo = 3.3V Tj = 25°C Vcc=5V Tamb=25°C Vo=1.8V Tj = 125°C 0.4 0.6 0.8 Io(A) 1 1.2 1.4 1.6 0 0.5 Io (A) 1 1.5 Figure 4. Tj(°C) Junction temperature vs. output current Figure 5. Vo (V) 3.312 Line regulator 130 120 110 100 90 80 70 60 50 40 30 20 0.2 Vo=5V Vcc=12V Tamb=25°C Vo=3.3V 3.308 3.304 3.3 3.296 3.292 3.288 3.284 3.28 3.276 Vcc = 12V Vo = 3.3V Tj = 25°C Vo=2.5V Tj = 125°C 0.4 0.6 0.8 Io(A) 1 1.2 1.4 1.6 0 10 20 Vcc (V) 30 40 Figure 6. Junction temperature vs. output current Figure 7. Vo (V) 1.25 Output voltage vs. junction temperature Tj(°C) 140 120 100 80 60 40 20 0 0.2 Vcc=24V Tam b=25°C Vo=18V Vo=12V 1.24 Vo=5V 1.23 1.22 Vcc = 12V 1.21 1.2 Vcc=12V 0.4 0.6 0.8 Io(A) 1 1.2 1.4 -50 0 50 Tj (°C) 100 150 7/16 Typical characteristics L5970D Figure 8. Iq (mA) Quiescent current vs. junction temperature Figure 9. Fsw (KHz) 260 Switching frequency vs. junction temperature 2 1.8 250 1.6 Vcc = 12V DC = 0% 240 1.4 230 Vcc = 12V Vo = 3.3V 1.2 -50 0 50 Tj (°C) 100 150 220 -50 0 50 Tj (C) 100 150 Figure 10. Shutdown current vs.junction Figure 11. Efficiency vs. output current temperature Ishd (µA) 70 Vcc = 12V Efficiency (%) 60 50 40 30 -50 0 50 Tj (°C) 100 150 94 92 90 88 86 84 82 80 78 76 74 72 70 0.1 Vo=3.3V Vo=2.5V Vo=1.8V Vcc=5V 0.2 0.3 0.4 0.5 0.6 Io (A) 0.7 0.8 0.9 1 Figure 12. Efficiency vs. output current 92 90 88 86 84 82 80 78 76 74 72 70 Vo=5V Vo=3.3V Efficiency (%) Vo=2.5V Vcc=12V 0.1 0.2 0.3 0.4 0.5 0.6 Io (A) 0.7 0.8 0.9 1 8/16 L5970D Application circuit 5 Application circuit Figure 13. Demo board application circuit VREF VCC SYNC. C1 10µF 25V CERAMIC COMP C4 22nF C3 220pF 3.3V VIN = 4.4V to 25V 6 8 2 4 INH. 1 OUT L1 33µH D1 STPS2L25U VOUT=3.3V L5970D 3 7 5 GND FB R1 5.6K C2 100µF 10V R3 4.7K R2 3.3K D03IN1437 Table 5. Component list Reference C1 C2 C3 C4 R1 R2 R3 D1 L1 STPS2L25U DO3316P-333 Part number C3225X5R1E106M POSCAP 10TPB100M C1206C221J5GAC C1206C223K5RAC Description 10µF, 25V 100µF, 10V 220pF, 5%, 50V 22nF, 10%, 50V 5.6K, 1%, 0.1W 0603 3.3K, 1%, 0.1W 0603 4.7K, 1%, 0.1W 0603 2A, 25V 33µH, 2A Manufacturer TDK Sanyo KEMET KEMET Neohm Neohm Neohm STMicroelectronics COILCRAFT 9/16 Application circuit Figure 14. PCB layout (component side) L5970D 42mm 34mm Figure 15. PCB layout (bottom side) Figure 16. PCB layout (front side) 10/16 L5970D Application ideas 6 Application ideas Figure 17. Dual output voltage with auxiliary winding N1/N2=2 D2 1N4148 VOUT1=5V 30mA VIN=12V VCC OUT Lp=22uH D1 STPS25L25U 8 COMP C1 10uF 25V Ceramic 1 U1 L5970D FB VOUT=3.3V 0.5A C4 100uF 10V C5 47uF 10V 4 2 6 GND 7 5 3 INH C2 220pF C3 22nF R3 4.7k SYNC VREF 3.3V Figure 18. Buck-boost regulator VIN=12V VCC OUT L1 33uH 8 U1 COMP C1 10uF 25V Ceramic C2 10uF C3 35V Ceramic 220pF 1 D1 STPS2L25U 2.7k VOUT=-12V/0.3A L5970 4 2 6 GND 7 5 3 FB C4 22nF R3 4.7k SYNC VREF INH 24k C5 100uF 16V 3.3V Vin=12V Vout=-12V Iout=0.5A Efficiency=81% Figure 19. Positive Buck-Boost regulator VIN=5V L1 33uH VCC 8 U1 L5970 4 2 6 GND OUT D2 STPS2L25U VOUT=12V/0.3A 1 D1 STPS2L25U 24k COMP C1 10uF 25V Ceramic 7 5 3 FB C2 220pF C3 22nF R3 4.7k M1 STN4NE03L 2.7k SYNC VREF INH C4 100uF 16V 3.3V Vin=5V Vout=12V Iout=0.3A Efficiency=76% Figure 20. Synchronization example VIN VCC OUT V CC OUT 8 L5970D 4 2 SYNC VREF 1 FB COMP 8 L5970D 4 2 SYNC VREF 1 FB COMP 6 GND 7 5 3 6 GND 7 5 3 INH INH 11/16 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 12/16 L5970D Package mechanical data Table 6. MSOP8 Mechanical data mm. Dim. Min A A1 A2 b c D (1) E E1 (1) e L L1 k aaa 0.400 0.050 0.750 0.250 0.130 2.900 4.650 2.900 3.000 4.900 3.000 0.650 0.550 0.950 0° (min.) 6° (max.) 0.100 0.004 0.700 0.016 0.850 Typ Max 1.10 0.150 0.950 0.400 0.230 3.100 5.150 3.100 0.002 0.03 0.010 0.005 0.114 0.183 0.114 0.118 0.193 0.118 0.026 0.022 0.037 0.028 0.033 Min Typ Max 0.043 0.006 0.037 0.016 0.009 0.122 0.20 0.122 inch 1. D and F does not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch) per side. Figure 21. Package dimensions 13/16 Order code L5970D 8 Order code Table 7. Order code Part number L5970D L5970D013TR Package SO8 SO8 Packaging Tube Tape and reel 14/16 L5970D Revision history 9 Revision history Table 8. Revision history Date 26-Jan-2007 Revision 14 Updated Table 5 on page 9 Changes 15/16 L5970D Please Read Carefully: Information in this document is provided solely in connection with ST products. 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