A5973D

A5973D Up to 2 A step down switching regulator for automotive applications Features ■ Qualified following the AEC-Q100 requirements (temperature grade 3), see PPAP for more details. 2 A DC output current Operating input voltage from 4 V to 36 V 3.3 V / (±2 %) reference voltage 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 The A5973D is a step down monolithic power switching regulator with a minimum switch current limit of 2.25 A so it is able to deliver more than 2 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 high current level is also achieved thanks to an HSOP8 package with exposed frame, that allows to reduce the Rth(JA) down to approximately 40°C/W. The device uses an internal P-channel DMOS 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. Pulse by pulse current limit with the internal frequency modulation offers an effective constant current short circuit protection. L1 15uH ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ HSOP8 exposed pad Description Application ■ Dedicated to automotive applications Figure 1. Application schematic VCC COMP C4 VIN=4V to 35V 8 4 1 2 OUT O UT SYNCH Vout=3.3V A5973D FB 6 5 7 GND INH 3 D1 STPS340U R1 5k6 C2 330uF 6.3V R2 3k3 C1 10uF 35V CERAM IC C3 220pF 22nF R3 4k7 VREF 3.3V August 2008 Rev 5 1/11 www.st.com 1 A5973D 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2/11 Pin settings A5973D 1 1.1 Pin settings Pin connection Figure 1. Pin connection (top view) 1.2 Pin description Table 1. N 1 2 3 4 5 6 7 8 Pin description Pin OUT SYNCH 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 1.23 V. An external resistive divider is required for higher output voltages. 3.3 V VREF. No cap is requested for stability. Ground. Unregulated DC input voltage. Description 3/11 A5973D 2 2.1 Electrical data Maximum ratings Table 2. Symbol V8 V1 I1 V4 , V5 V3 V2 PTOT TJ TSTG Input voltage OUT pin DC voltage OUT pin peak voltage at Δt = 0.1 μs Maximum output current Analog pins INH SYNCH 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 -0.3 to VCC -0.3 to 4 2.25 -40 to 150 -55 to 150 V V 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 40 (1) Unit °C/W 1. Package mounted on board 4/11 Electrical characteristics A5973D 3 Electrical characteristics Table 4. Symbol VCC RDS(on) IL fSW Electrical characteristics (TJ = -40 °C 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 Test condition V0 = 1.235 V; I0 = 2 A Min 4 0.250 Typ Max 36 0.5 3.5 A 2.5 212 0 3 250 3.5 280 100 kHz % Unit V Ω VCC = 5 V VCC = 5 V, TJ = 25 °C 2.25 3 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 Iqst-by Inhibit Device ON INH threshold voltage Device OFF Error amplifier VOH VOL Io source Io sink Ib High level output voltage Low level output voltage Source output current Sink output current Source bias current DC open loop gain RL = ∞ 50 VFB = 1 V VFB = 1.5 V VCOMP = 1.9 V; VFB = 1 V VCOMP = 1.9 V; VFB = 1.5 V 190 1 300 1.5 2.5 65 4 3.5 0.4 V V μA mA μA dB 2.2 V 0.8 V Total operating quiescent current Quiescent current Total stand-by quiescent current Duty cycle = 0; VFB = 1.5 V Vinh > 2.2 V VC C = 36 V; Vinh > 2.2 V 50 80 3 5 2.5 100 150 mA mA μA μA 5/11 A5973D Table 4. Symbol gm Electrical characteristics (continued) (TJ = -40 °C to 125 °C, VCC = 12 V, unless otherwise specified) Parameter Transconductance Test condition ICOMP = -0.1 mA to 0.1 mA; VCOMP = 1.9 V Min Typ 2.3 Max Unit mS Synch function High input voltage Low input voltage Slave synch current Master output amplitude Output pulse width Reference section Reference voltage IREF = 0 to 5 mA VCC = 4.4 V to 36 V Line regulation Load regulation Short circuit current IREF = 0 mA VCC = 4.4 V to 36 V IREF = 0 mA 5 8 18 15 35 mV mA 5 10 mV 3.2 3.3 3.399 V VCC = 4.4 to 36 V; VCC = 4.4 to 36 V; Vsynch = 0.74 V (2) Vsynch = 2.33 V Isource = 3 mA no load, Vsynch = 1.65 V 0.11 0.21 2.75 0.20 3 0.35 2.5 VREF 0.74 0.25 0.45 V V mA V μs 1. With TJ = 85 °C, Ilim_min = 2.5 A, assured by design, characterization and statistical correlation. 2. Guarantee by design 6/11 Typical characteristics A5973D 4 Typical characteristics Figure 2. Line regulator Figure 3. Shutdown current vs junction temperature Figure 4. Output voltage vs junction temperature Figure 5. Switching frequency vs junction temperature Figure 6. Quiescent current vs junction temperature 7/11 A5973D Figure 7. Junction temperature vs output current Figure 8. Junction temperature vs output current Figure 9. Efficiency vs output current Figure 10. Efficiency vs output current 8/11 Package mechanical data A5973D 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 9/11 A5973D Table 5. Dim Min A A1 A2 b c D D1 E E1 E2 e h L k ccc 0.25 0.40 0.00 1.25 0.31 0.17 4.80 3 5.80 3.80 2.31 4.90 3.1 6.00 3.90 2.41 1.27 0.50 1.27 0.0098 0.0157 0.0197 0.0500 0.51 0.25 5.00 3.2 6.20 4.00 2.51 Typ Max 1.70 0.10 0.0492 0.0122 0.0067 0.1890 0.118 0.2283 0.1496 0.091 0.095 0.1929 0.122 0.0201 0.0098 0.1969 0.126 0.2441 0.1575 0.099 0.00 Min Typ Max 0.0669 0.0039 HSOP8 mechanical data mm inch 0° (min), 8° (max) 0.10 0.0039 Figure 11. Package dimensions 10/11 Revision history A5973D 6 Revision history Table 6. Date 06-Aug-2007 23-Oct-2007 07-Jan-2008 06-May-2008 29-Aug-2008 Document revision history Revision 1 2 3 4 5 Initial release Updated: Table 4 on page 5, Table 5 on page 10 Updated Table 5 on page 10 Updated Table 4 on page 5 Updated Table 4 on page 5 Changes 11/11 A5973D Please Read Carefully: Information in this document is provided solely in connection with ST products. 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