A5972D_0808

A5972D Up to 1.5 A step down switching regulator for automotive applications Features ■ Qualified following the AEC-Q100 requirements (temperature grade 3), see PPAP for more details. 1.5 A DC output current Operating input voltage from 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 The A5972D is a step down monolithic power switching regulator with a minimum switch current limit of 1.8 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 1.235V to 35V. The device uses an internal P-channel D-MOS transistor (with a typical RDS(on) of 250 mΩ) as switching element to minimize the size of the external components. An internal oscillator fixes the switching frequency at 250 kHz. Having a minimum input voltage of 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. SO-8 ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Description Applications ■ Automotive applications Figure 1. Application schematic 33uH VIN=4.4V to 35V VCC COM P O UT VO UT=3.3V C4 C1 10uF C3 220pF 4.7K Ω R3 22nF A5972D GND FB D1 STPS2L40U R1 5.6K C2 100uF R2 3.3K August 2008 Rev 4 1/11 www.st.com 1 A5972D Contents 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 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2/11 A5972D 1 1.1 Pin settings Pin connection Figure 1. Pin connection (top view) 1.2 Pin description Table 1. N° 1 2,3,6,7 4 5 8 Pin description Pin OUT GND COMP FB VCC Regulator output. Ground. E/A output for frequency compensation. Feedback input. Connecting directly to this pin results in an output voltage of 1.23 V. An extenal resistive divider is required for higher output voltages. Unregulated DC input voltage. Description 3/11 Electrical data A5972D 2 2.1 Electrical data Maximum ratings Table 2. Symbol V8 V1 I1 V4 , V5 PTOT TJ TSTG Input voltage OUT pin DC voltage OUT pin peak voltage at Δt = 0.1 μs Maximum output current Analog pins Power dissipation at TA ≤ 70 °C Operating junction temperature range Storage temperature range Absolute maximum ratings Parameter Value 40 -1 to 40 -5 to 40 int. limit. 4 1.2 -40 to 150 -55 to 150 V W °C °C Unit V V V 2.2 Thermal data Table 3. Symbol RthJA Thermal data Parameter Maximum thermal resistance junction-ambient SO8 65 (1) Unit °C/W 1. Package mounted on board 4/11 A5972D 3 Electrical characteristics Table 4. Symbol VCC RDS(on) IL fSW Electrical characteristics (TJ = -40 to 125 °C, VCC = 12 V, unless otherwise specified) Parameter Operating input voltage range Mosfet on resistance Maximum limiting current (1) Switching frequency Duty cycle VCC = 5 V VCC = 5 V, TJ = 25 °C 1.8 2 212 0 Test condition V0 = 1.235 V; I0 = 2 A Min 4 0.250 2.5 2.5 250 Typ Max 36 0.5 3 A 3 280 100 kHz % Unit V Ω Dynamic characteristics (see test circuit) V5 η Voltage feedback Efficiency 4.4 V < VCC < 36 V, 20 mA < I0 < 2 A V0 = 5 V, VCC = 12 V 1.198 1.235 90 1.272 V % DC characteristics Iqop Iq Total operating quiescent current Quiescent current Duty cycle = 0; VFB= 1.5 V 3 5 2.5 mA mA Error amplifier VOH VOL Io source High level output voltage Low level output voltage Source output current VFB = 1 V VFB = 1.5 V VCOMP = 1.9 V; VFB = 1 V VCOMP = 1.9 V; VFB = 1.5 V Source bias current DC open loop gain gm Transconductance RL= 50 2.5 65 2.3 4 μA dB mS 1 1.5 190 300 3.5 0.4 V V μA Io sink Ib Sink output current mA ICOMP = -0.1 mA to 0.1 mA; VCOMP = 1.9 V 1. With TJ = 85 °C, Ilim_min = 2 A, assured by design, characterization and statistical correlation. 8 5/11 Typical characteristics A5972D 4 Typical characteristics Figure 2. Output voltage vs junction temperature Figure 3. Quiescent current vs junction temperature Figure 4. Line regulatior Figure 5. Shutdown current vs junction temperature Figure 6. Output voltage vs junction temperature Figure 7. Junction temperature vs output current 6/11 A5972D Figure 8. Junction temperature vs output current Figure 9. Efficiency vs output current Figure 10. Efficiency vs output current 7/11 Package mechanical data A5972D 5 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 8/11 A5972D Table 5. Dim SO-8 mechanical data mm Min Typ Max 1.75 0.25 1.65 0.51 0.25 5.00 4.00 1.27 5.80 0.25 0.40 6.20 0.50 1.27 0.228 0.010 0.016 Min 0.053 0.004 0.043 0.013 0.007 0.189 0.15 0.050 0.244 0.020 0.050 inch Typ Max 0.069 0.010 0.065 0.020 0.010 0.197 0.157 A A1 A2 B C D (1) E e H h L k ddd 1.35 0.10 1.10 0.33 0.19 4.80 3.80 0° (min), 8° (max) 0.10 0.004 1. Dimension D does not include mold flash, protrusions or gate burrs. Mold flash, protrusions or gate burrs shall not exceed 0.15mm (0.006 inch) in total (both side). Figure 11. SO-8 mechanical data 9/11 Revision history A5972D 6 Revision history Table 6. Date 06-Aug-2007 5-Nov-2007 2-May-2008 27-Aug-2008 Document revision history Revision 1 2 3 4 Initial release Updated: Table 4 on page 5 Updated: Cover page, Table 4 on page 5 Updated: Coverpage and Table 4 on page 5 Changes 10/11 A5972D 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. Purchasers are solely responsible for the choice, selection and use of the ST products and services described herein, and ST assumes no liability whatsoever relating to the choice, selection or use of the ST products and services described herein. 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