A5970D 1.5A 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 ■ Up to 1 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 ■ Inhibit for zero current consumption ■ Synchronization ■ Protection against feedback disconnection ■ Thermal shutdown SO-8 Description The A5970D is a step down monolithic power switching regulator capable to deliver up to 1 A at output voltages from 1.2 V to 35 V. The device uses an internal P-channel D-MOS transistor (with a typical Rdson 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 4.4 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. Applications ■ Dedicated to automotive applications Figure 1. Typical application L1 33uH VIN=4.4V to 35V VCC 8 1 4 2 SYNCH COMP C4 C1 A5970D 22nF 6 35V October 2007 D1 R1 STPS340U 5k6 C2 100uF 10V FB 10uF CERAMIC Vout=3.3V OUT C3 R3 220pF 4k7 VREF 3.3V 5 7 GND 3 INH R2 3k3 Rev 2 1/13 www.st.com 1 Contents A5970D Contents 1 2 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 5 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 6 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 7 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2/13 A5970D 1 Pin settings 1.1 Pin connection Figure 2. Pin connection (top view) OUT 1 8 VCC SYNC 2 7 GND INH 3 6 VREF COMP 4 5 FB D98IN955 1.2 Pin description Table 1. Pin description N Pin Description 1 OUT 2 SYNCH 3 INH 4 COMP 5 FB 6 VREF 3.3V VREF. No cap is requested for stability. 7 GND Ground. 8 VCC Unregulated DC input voltage. 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 extenal resistive divider is required for higher output voltages. 3/13 Electrical data A5970D 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. Analog pins 4 V -0.3 to VCC V -0.3 to 4 V 0.75 W Operating junction temperature range -40 to 150 °C Storage temperature range -55 to 150 °C SO8 Unit 120 (1) °C/W V3 INH V2 SYNCH PTOT TJ TSTG 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 4/13 Value V8 V4 , V5 2.2 Parameter A5970D 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=1A Min Max Unit 36 V 0.250 0.5 Ω 1.5 1.87 2.25 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 Iqst-by 3 5 mA 2.5 mA 50 100 µA 80 150 µA 0.8 V Duty ycle=0; VFB=1.5V Vinh > 2.2V Total stand-by quiescent VCC=36V; current Vinh > 2.2V Inhibit Device ON INH threshold voltage Device OFF 2.2 V 3.5 V Error amplifier VOH High level output voltage VFB=1V VOL Low level output voltage VFB=1.5V 0.4 V Source output current VCOMP = 1.9V; VFB = 1V 190 300 µA Io sink Sink output current VCOMP = 1.9V; VFB = 1.5V 1 1.5 mA Ib Source bias current Io source gm 2.5 DC open loop gain RL= ∞ Transconductance ICOMP = -0.1mA to 0.1mA; VCOMP = 1.9V 50 4 µA 65 dB 2.3 mS 5/13 Electrical characteristics Table 4. A5970D Electrical characteristics (TJ=-40 to 85°C, VCC = 12V, unless otherwise specified) Symbol Parameter Test condition Min Typ Max Unit VREF V 0.74 V 0.25 0.45 mA Synch function High input voltage VCC= 4.4 to 36V; Low input voltage VCC= 4.4 to 36V; Slave synch current Vsynch= 0.74V Vsynch= 2.33V (1) Master output amplitude Isource= 3mA 2.5 0.11 0.21 2.75 3 V no load, Vsynch= 1.65V 0.20 0.35 µs Reference voltage IREF = 0 to 5mA VCC = 4.4V to 36V 3.2 3.3 3.399 V Line regulation IREF = 0mA VCC = 4.4V to 36V 5 10 mV Load regulation IREF = 0mA 8 15 mV 18 30 mA Output pulse width Reference section Short circuit current 1. Guaranteed by design 6/13 10 A5970D 4 Typical characteristics Figure 3. Junction temperature vs. output current Figure 4. Vo (V) 3.312 Tj(°C) 130 120 110 100 90 80 70 60 50 40 30 20 Vo=3.3V Vcc=5V Tamb=25°C Vo=2.5V Vo=1.8V Load regulator Vcc = 12V Vo = 3.3V 3.308 3.304 Tj = 25°C 3.3 3.296 3.292 3.288 3.284 Tj = 125°C 3.28 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 3.276 0 0.5 Figure 5. 1 1.5 Io (A) Io(A) Junction temperature vs. output current Figure 6. Line regulator Vo (V) Tj(°C) 3.312 130 120 110 100 90 80 70 60 50 40 30 20 Vo=3.3V Vo=5V Vcc = 12V Vo = 3.3V 3.308 3.304 Vo=2.5V Vcc=12V Tamb=25°C Tj = 25°C 3.3 3.296 3.292 Tj = 125°C 3.288 3.284 3.28 3.276 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0 Io(A) Figure 7. Junction temperature vs. output current 20 Vcc (V) 30 40 Output voltage vs. junction temperature Vo (V) 1.25 Tj(°C) 140 Vo=18V Vo=12V 1.24 120 100 Figure 8. 10 Vo=5V Vcc=24V Tamb=25°C 1.23 80 1.22 60 Vcc = 12V 40 1.21 Vcc=12V 20 0 0.2 1.2 0.4 0.6 0.8 Io(A) 1 1.2 1.4 -50 0 50 Tj (°C) 100 150 7/13 Typical characteristics A5970D Figure 9. Quiescent current vs. junction temperature Figure 10. Switching frequency vs. junction temperature Iq (mA) 2 Fsw (KHz) 260 1.8 250 1.6 240 Vcc = 12V DC = 0% 1.4 Vcc = 12V Vo = 3.3V 230 1.2 220 -50 0 50 Tj (°C) 100 150 -50 0 50 Tj (C) 100 150 Figure 11. Shutdown current vs.junction Figure 12. Efficiency vs. output current temperature Ishd (µA) 60 Efficiency (%) 70 Vcc = 12V 50 40 30 -50 50 Tj (°C) 0 100 150 Efficiency (%) Figure 13. Efficiency vs. output current 8/13 92 90 88 86 84 82 80 78 76 74 72 70 Vo=5V Vo=3.3V 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 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 A5970D 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 9/13 Package mechanical data Table 5. A5970D 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 14. Package dimensions 10/13 A5970D 6 Order codes Table 6. Order code Order code Package A5970D Packing Tube SO-8 A5970D13TR Tape and reel 11/13 Revision history 7 A5970D Revision history Table 7. 12/13 Document revision history Date Revision Changes 06-Aug-2007 1 Initial release. 24-Oct-2007 2 Updated: Table 4 on page 5 A5970D 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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