A5972D 2A switch step down switching regulator for automotive applications Features ■ Qualified following the AEC-Q100 requirements (temperature Grade 3), see PPAP for more details. ■ Temperature range -40 °C to 85 °C ■ 1.5 A DC output current ■ Operating input voltage from 4.4 V to 36 V ■ Output voltage adjustable from 1.235 V to 35 V ■ Low dropout operation: 100% duty cycle ■ 250 kHz internally fixed frequency ■ Voltage feedforward ■ Zero load current operation ■ Internal current limiting ■ Protection against feedback disconnection ■ Thermal shutdown SO8 Description The A5972D is a step down monolithic power switching regulator with a minimum switch current limit of 2 A so it is able to deliver more than 1.5 A DC current to the load depending on the application conditions. The output voltage can be set from 1.235 V to 35 V. The device uses an internal P-channel DMOS transistor (with a typical Rdson of 250 mΩ) as switching element to minimize the size of the external components. Applications ■ An internal oscillator fixes the switching frequency at 250 kHz. Dedicated to automotive applications Having a minimum input voltage of 4.4 V only, it is particularly suitable for 5 V bus. Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection. Figure 1. Typical application L1 33uH VIN=4.4V to 35V VCC COM P C4 22nF C1 A5972D D1 STPS2L40U 10uF VO U T=3.3V OUT GND R1 C2 100uF 5.6K FB C3 220pF 4.7KΩ R2 R3 November 2007 3.3K Rev 2 1/12 www.st.com 1 Contents A5972D Contents 1 2 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 4 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2/12 A5972D 1 Pin settings 1.1 Pin connection Figure 2. 1.2 Pin connection (top view) Pin description Table 1. Pin description N Pin Description 1 OUT Regulator output. 2,3,6,7 GND Ground. 4 COMP 5 FB 8 VCC E/A output for frequency compensation. Feedback input. Connecting directly to this pin results in an output voltage of 1.23V. An extenal resistive divider is required for higher output voltages. Unregulated DC input voltage. 3/12 Electrical data A5972D 2 Electrical data 2.1 Maximum ratings Table 2. Absolute maximum ratings Symbol Unit 40 V V V Input voltage V1 OUT pin DC voltage OUT pin peak voltage at ∆t=0.1µs -1 to 40 -5 to 40 I1 Maximum output current int. limit. PTOT Tj TSTG Analog pins 4 V 1.2 W Operating junction temperature range -40 to 150 °C Storage temperature range -55 to 150 °C SO8 Unit 65 (1) °C/W Power dissipation at TA ≤ 70°C Thermal data Table 3. Thermal data Symbol RthJA Parameter Maximum thermal resistance junction-ambient 1. Package mounted on board 4/12 Value V8 V4 , V5 2.2 Parameter A5972D 3 Electrical characteristics Table 4. Electrical characteristics (TJ=-40 to 85°C, VCC = 12V, unless otherwise specified) Symbol Parameter VCC Operating input voltage range RDS(on) IL fSW Test condition V0=1.235V; I0=2A Min Max Unit 36 V 0.250 0.5 Ω 2 2.5 3 A 212 250 280 kHz 100 % 1.272 V 4.4 Mosfet on resistance Maximum limiting current VCC=5V Switching frequency Duty cycle Typ 0 Dynamic characteristics (see test circuit). V5 Voltage feedback 4.4V<VCC<36V, 20mA<I0<2A η Efficiency V0=5V, VCC=12V 1.198 1.235 90 % DC characteristics Iqop Total operating quiescent current Iq Quiescent current 3 Duty cycle=0; VFB=1.5V 5 mA 2.5 mA Error amplifier VOH High level output voltage VFB=1V VOL Low level output voltage VFB=1.5V Io source Io sink Source output current Sink output current VCOMP = 1.9V; 3.5 V 0.4 190 300 µA 1 1.5 mA VFB = 1V VCOMP = 1.9V; V VFB = 1.5V Ib Source bias current DC open loop gain gm Transconductance 2.5 RL= ∞ ICOMP = -0.1mA to 50 4 µA 65 dB 2.3 mS 0.1mA; VCOMP = 1.9V 5/12 Typical characteristics 4 6/12 A5972D Typical characteristics Figure 3. Output voltage vs junction temperature Figure 4. Line regulatior Figure 5. Output voltage vs junction temperature Figure 6. Quiescent current vs junction temperature Figure 7. Shutdown current vs junction Figure 8. temperature Junction temperature vs output current A5972D Figure 9. Junction temperature vs output current Figure 10. Efficiency vs. output current Figure 11. Efficiency vs output current 7/12 Package mechanical data 5 A5972D 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 8/12 A5972D Table 5. SO-8 mechanical data mm. inch Dim. Min Typ Max Min Typ Max A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.004 0.010 A2 1.10 1.65 0.043 0.065 B 0.33 0.51 0.013 0.020 C 0.19 0.25 0.007 0.010 (1) 4.80 5.00 0.189 0.197 E 3.80 4.00 0.15 0.157 D e 1.27 0.050 H 5.80 6.20 0.228 0.244 h 0.25 0.50 0.010 0.020 L 0.40 1.27 0.016 0.050 k ddd 0° (min.), 8° (max.) 0.10 0.004 1. Dimensions D does not include mold flash, protru-sions or gate burrs. Mold flash, potrusions or gate burrs shall not exceed 0.15mm (.006inch) in total (both side). Figure 12. Package dimensions 9/12 Order codes 6 A5972D Order codes Table 6. Order code Order code Package A5972D Packing Tube SO8 A5972D013TR 10/12 Tape and reel A5972D 7 Revision history Table 7. Document revision history Date Revision Changes 06-Aug-2007 1 Initial release 5-Nov-2007 2 Updated: Table 4 on page 5 11/12 A5972D Rev 1 Please Read Carefully: Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. 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