ST890 1.2 A current limited high side power switch with thermal shutdown Features 2.7 V to 5.5 V input range Programmable current limit up to 1.2 A Low quiescent current Thermal shutdown Active low FAULT indicator output 90 m (typ.) ON resistance SO-8 and DFN8L (3 x 3 mm) packages SO-8 DFN8L (3 x 3 mm) Description Applications PCMCIA slots Access bus slots Portable equipment The ST890 is a low voltage, P-channel MOSFET power switch intended for high side load switching applications. The switch operates with inputs from 2.7 V to 5.5 V, making it ideal for both 3 V and 5 V systems. The internal current limiting circuitry protects the input supply against overload. The thermal overload protection limits power dissipation and junction temperatures. The maximum current limit is 1.2 A. The current limit through the switch is programmed with a resistor from SET to ground. The devices are available in SO-8 and DFN8L (3 x 3 mm) packages. Table 1. March 2009 Device summary Order code Package Packaging ST890BDR SO-8 2500 parts per reel ST890CDR SO-8 2500 parts per reel ST890DTR DFN8L (3 x 3 mm) 3000 parts per reel Rev 8 1/20 www.st.com 20 Contents ST890 Contents 1 Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 2.2 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.1 Output current limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.2 Output short circuit protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.3 Programming ILIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.4 Fault pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.5 Thermal protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2/20 ST890 1 Device summary Device summary Figure 1. SO-8 pin connection (top view) IN 1 8 FAULT IN 2 7 OUT ON 3 6 OUT GND 4 5 SET CS07570 Table 2. SO-8 pin description Pin N. Symbol Name and function 1, 2 IN Input P-channel MOSFET source. Bypass IN with a 1 F capacitor to ground 3 ON Active low switch ON input. A logic low turns the switch ON 4 GND Ground 5 SET Set current limit input. A resistor from SET to GND sets the current limit for the switch. RSET = 1.24x1110/ ILIM, where ILIM is the desired current limit in Amperes 6,7 OUT Switch output. P-channel MOSFET drain. Bypass OUT with a 0.1 F capacitor to ground 8 FAULT Fault indicator output. This open drain output goes low when in current limit or when the die temperature exceeds 135C 3/20 Device summary ST890 Figure 2. DFN8L (3 x 3 mm) pin connection (top view) IN 1 8 FAULT IN 2 7 OUT ON 3 6 OUT GND 4 5 SET CS00025 Table 3. 4/20 DFN8L (3 x 3 mm) pin description Pin N. Symbol Name and function 1, 2 IN Input P-channel MOSFET source. Bypass IN with a 1 F capacitor to ground 3 ON Active low switch ON input. A logic low turns the switch ON 4 GND Ground 5 SET Set current limit input. A resistor from SET to GND sets the current limit for the switch. 6,7 OUT Switch output. P-channel MOSFET drain. Bypass OUT with a 0.1 F capacitor to ground. RSET = 1.24x1110/ILIM, where ILIM is the desired current limit in Amperes 8 FAULT Fault indicator output. This open drain output goes low when in current limit or when the die temperature exceeds 135 C ST890 Device summary Figure 3. Schematic diagram OUT IN - + ON /FAULT Replica amplifier + SET ON - 1.24V Current limit amplifier Control circuitry /ON GND CS00026 Table 4. Table 5. Truth table for ON/OFF switch ON/OFF OUT L ON H OFF Truth table for FAULT FAULT FLAG H Normal operation L Fault condition 5/20 Maximum rating 2 ST890 Maximum rating Stressing the device above the rating listed in the "Absolute maximum ratings" table may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other conditions above those indicated in the operating sections of this specification is not implied. Exposure to Absolute maximum rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other relevant quality documents. Table 6. Absolute maximum ratings Symbol Parameter VI VON VFAULT_N Value Unit Supply voltage -0.5 to +6 V Input voltage at ON pin -0.5 to +6 V Input voltage at FAULT_N pin -0.5 to +6 V -0.5 to (VIN +0.5) V 1.5 A Voltage at SET pin VSET IDS Maximum continuous switching current Tstg Storage temperature -65 to +150 C Top Operating ambient temperature range -40 to +85 C Table 7. Thermal data Symbol Parameter SO-8 DFN8L Unit Rthj-amb Thermal resistance junction-ambient 160(1) 37.6(2) C/W 1. This value depends from thermal design of PCB on which the device is mounted. 2. This value depends from the 4-layer PCB, JEDEC standard test board. Table 8. Electrical characteristics Value Symbol Parameter Test condition(1) TA = 25C Min VI Operating voltage ID = 1 mA ICC ON quiescent supply current I(CCOFF) 6/20 OFF quiescent supply current VI = 5 V, ON = GND IO = 0 Typ 2.7 13 Unit Max 5.5 V 25 A ON = IN VI = VOUT = 5.5 V 1 ON = IN VI = 5.5 V VO = 0 5 A ST890 Maximum rating Table 8. Electrical characteristics (continued) Value Symbol Parameter VULO Undervoltage lockout VHYST Undervoltage lockout hysteresis RON VSET IMAX ISC ILIM/ISET ON resistance Test condition(1) Rising edge Min Typ Max 2.0 2.4 2.6 V mV VI = 4.5 V 75 120 m VI = 3 V 90 130 m 1.24 1.302 Reference voltage IO = 100 mA to turn the switch VSET rise until VI - VO > OFF 0.8V 1.178 V Maximum programmable output over current limit Short circuit current limit Unit 100 1.2 A VI = 5V, OUT connected to GND, device enabled into short circuit ILIM to ISET current IO = 500 mA ratio VO > 1.6 V VIL ON input low level VI = 2.7 to 5.5 V voltage VIH ON input high level voltage 970 1.2 ILIM 1.5 ILIM 1110 1300 0.8 A V VI = 2.7 to 3.6 V 2.0 V VI = 2.7 to 5.5 V 2.4 V ON input leakage current VI = 5.5 V ISET bias ISET bias current VSET = 1.24 V IO = 0A VI = VO VOL FAULT output low voltage IOH FAULT output high VFAULT = 5.5 V voltage VSET = 1 V II TA = 25C ISINK = 1 mA VSET = 1.4 V 0.5 1 A 3 A 0.15 V 1 A TPROT Thermal protection 130 C THYST Thermal hysteresis 15 C 1. VIN = 3 V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at TA = 25C 7/20 Maximum rating ST890 Table 9. Timing characteristics Value Symbol Parameter Test condition(1) TA = 25C Min Slow current loop response time tRESP tON Typ 20% current overdrive, VCC = 5 V Fast current loop response time Unit Max 5 s 2 s VI = 5 V IO = 500 mA 25 VI = 3 V IO = 500 mA 50 s 50 Turn ON time tOFF Turn OFF time VI = 5 V 1 2 s s 10 1. VIN = 3 V, TA = TMIN to TMAX, unless otherwise specified. Typical values are at TA = 25 C Figure 4. Typical application circuit INPUT 100 k IN OUT IN OUT /FAULT /ON GND SET OUTPUT 0.1F ON/OFF 1F R SET CS00027 8/20 ST890 Maximum rating 2.1 Functional description 2.1.1 Output current limit ILIM is the output current that ST890 limits under the condition VO (output voltage) > 1.6 V. When ILIM is reached, the Fault pin is asserted. 2.1.2 Output short circuit protection The ST890 provides short circuit protection by limiting the output current during a short circuit event. Isc is the output short circuit current limit level (typ 1.2 x ILIM). When the output is short circuit such as VO < 1.6 V, the ST890 limits the output current to no more than the Isc level. When the output is short circuit, the Fault pin is asserted. 2.1.3 Programming ILIM The ST890's ILIM can be programmed through the external resistor, RSET connected at the SET pin (pin 5). ILIM is determined by the following relationships: Equation 1 ISET = VSET / R SET Equation 2 ILIM / ISET = 1110 therefore: Equation 3 R SET = 1.24 x 1110 / ILIM 2.1.4 Fault pin The Fault pin (pin 8) is an open drain active low output. This pin should be connected to an external pull-up resistor. The Fault pin is asserted low when: 2.1.5 - IOUT reaches the programmed ILIM value - A short circuit event occurs - The device goes into thermal protection Thermal protection The ST890's thermal protection is triggered to turn off the switch when the junction temperature exceeds 130C (typ). 9/20 Maximum rating 2.2 ST890 Typical performance characteristics Unless otherwise specified Tj = 25 C. 10/20 Figure 5. ON resistance vs. supply voltage Figure 6. ON resistance vs. temperature ST890 Maximum rating Figure 7. VCC=5V, R L=0.6 Switching waveforms VCC=5V, R L=0.32 11/20 Package mechanical data 3 ST890 Package mechanical data In order to meet environmental requirements, ST offers these devices in ECOPACK(R) 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. Figure 8. SO-8 package drawing 0016023/C 1. Drawing not to scale. 12/20 ST890 Package mechanical data Table 10. SO-8 package mechanical data millimeters inches Symbol Min Typ Max Min Typ Max A 1.35 1.75 0.053 0.069 A1 0.10 0.25 0.04 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 D 4.80 5.00 0.189 0.197 E 3.80 4.00 0.150 0.157 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 8(max) 0.1 0.04 13/20 Package mechanical data Figure 9. ST890 SO-8 tape and reel specifications 1. Drawing not to scale. Table 11. SO-8 tape and reel mechanical data millimeters inches Symbol Min A Max Min 330 13.2 Typ Max 12.992 C 12.8 D 20.2 0.795 N 60 2.362 T 14/20 Typ 0.504 22.4 0.519 0.882 Ao 8.1 8.5 0.319 0.335 Bo 5.5 5.9 0.216 0.232 Ko 2.1 2.3 0.082 0.090 Po 3.9 4.1 0.153 0.161 P 7.9 8.1 0.311 0.319 ST890 Package mechanical data Figure 10. DFN8L (3 x 3 mm) package drawing PO8092726_A 1. Drawing is not to scale. 2. Dimensions in millimeters. 15/20 Package mechanical data Table 12. ST890 DFN8L (3 x 3 mm) package mechanical data millimeters Symbol Min Typ Max A 0.80 0.85 0.90 A1 0 0.02 0.05 b 0.25 0.030 0.35 D 2.95 3 3.05 D2 2.30 2.40 2.50 E 2.95 3 3.05 E2 1.70 1.80 1.90 e L 0.65 0.25 0.30 0.35 Figure 11. DFN8L (3 x 3 mm) footprint recommendations FR8092726_A 1. Drawing not to scale. 2. Dimensions in millimeters. 16/20 ST890 Package mechanical data Figure 12. DFN8L (3 x 3 mm) tape and reel specifications 17/20 Package mechanical data Figure 13. DFN8L (3 x 3 mm) reel specifications 18/20 ST890 ST890 4 Revision history Revision history Table 13. Document revision history Date Revision Changes 22-Jul-2005 4 Added 3 rows on Table 2 on page 3 10-Aug-2007 5 Removed ST890CD and ST890BD from Table 1 on page 1 Updated short circuit current limit value in Table 8 on page 6 1-Dec-2007 6 Added Section : Contents. Added ST890D and related DFN8L package information. Added Figure 2: DFN8L (3 x 3 mm) pin connection (top view) on page 4. Figure 3: Schematic diagram on page 5: redrawn, no content change. Modified title in Table 5: Truth table for FAULT on page 5. Updated Table 8: Electrical characteristics on page 6. Figure 4: Typical application circuit on page 8: redrawn, no content change. 13-Oct-2008 7 Updated: Table 2 on page 3, Table 3 on page 4. Added: Section 2.1: Functional description on page 9 and Figure 12 on page 17. 04-Mar-2009 8 Replaced ST890B, ST890C and ST890D with ST890. 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