IFX91041 1.8A DC/DC Step-Down Voltage Regulator 5.0V, 3.3V or Adjustable Output Voltage IFX91041EJV50 IFX91041EJV33 IFX91041EJV Data Sheet Rev. 1.1, 2011-07-08 Standard Power 1.8A DC/DC Step-Down Voltage Regulator 1 • • • • • • • • • • • • • IFX91041 Overview 1.8A step down voltage regulator Output voltage versions: 5.0 V, 3.3 V and adjustable ± 2% output voltage tolerance (+-4% for full load current range) Integrated power transistor PWM regulation with feedforward Input voltage range from 4.75V to 45V 370 kHz switching frequency Synchronization input Very low shutdown current consumption (<2uA) Soft-start function Input undervoltage lockout Suited for industrial applications: Tj = -40 °C to +125°C Green Product (RoHS compliant) PG-DSO-8-27 For automotive and transportation applications, please refer to the Infineon TLE and TLF voltage regulator series. Description The IFX91041 series are monolithic integrated circuits that provide all active functions for a step-down (buck) switching voltage regulator, capable of driving up to 1.8A load current with excellent line and load regulation. These devices are suited for use in industrial applications featuring protection functions such as current limitation and overtemperature shutdown. Versions with a fixed 5.0V and 3.3V (IFX91041EJV50, IFX91041EJV33) output voltage as well as an adjustable device (IFX91041EJV) with 0.60V reference feedback voltage are available. The switching frequency of 370kHz allows to use small and inexpensive passive components. The IFX91041 features an enable function reducing the shut-down current consumption to <2uA. The voltage mode regulation scheme of this device provides a stable regulation loop maintained by small external compensation components. Besides the feedforward control path offers an excellent line transient rejection. The integrated soft-start feature limits the current peak as well as voltage overshot at start-up. Type Package Marking IFX91041EJV50 PG-DSO-8-27 I9104150 IFX91041EJV33 PG-DSO-8-27 I9104133 IFX91041EJV PG-DSO-8-27 I91041V Data Sheet 2 Rev. 1.1, 2011-07-08 IFX91041 Block Diagram 2 Block Diagram 7 EN 8 VS Enable Charge Pump Over Temperature Shutdown 5 BDS Feedforward COMP SYNC 3 1 Buck Converter 6 BUO Oscillator 4 Bandgap Reference FB Soft start ramp generator IFX91041 2 Figure 1 Data Sheet GND Block Diagram 3 Rev. 1.1, 2011-07-08 IFX91041 Pin Configuration 3 Pin Configuration 3.1 Pin Assignment SYNC 1 GND IFX91041 8 VS 2 7 EN COMP 3 6 BUO FB 4 5 BDS S08_PIN.vsd Figure 2 Pin Configuration 3.2 Pin Definitions and Functions Pin Symbol Function 1 SYNC Synchronization Input. Connect to an external clock signal in order to synchronize/adjust the switching frequency. If not used connect to GND. 2 GND Ground. 3 COMP Compensation Input. Frequency compensation for regulation loop stability. Connect to compensation RC-network. 4 FB Feedback Input. For the adjustable output voltage versions (IFX91041EJV) connect via voltage divider to output capacitor. For the fixed voltage version (IFX91041EJV50, IFX91041EJV33) connect this pin directly to the output capacitor. 5 BDS Buck Driver Supply Input. Connect the bootstrap capacitor between this pin and pin BUO. 6 BUO Buck Switch Output. Source of the integrated power-DMOS transistor. Connect directly to the cathode of the catch diode and the buck circuit inductance. 7 EN Enable Input. Active-high enable input with integrated pull down resistor. 8 VS Supply Voltage Input. Connect to supply voltage source. Exposed Pad Data Sheet Connect to heatsink area and GND by low inductance wiring. 4 Rev. 1.1, 2011-07-08 IFX91041 General Product Characteristics 4 General Product Characteristics 4.1 Absolute Maximum Ratings Absolute Maximum Ratings1) Tj = -40 °C to +125°C; all voltages with respect to ground (unless otherwise specified) Pos. Parameter Symbol Limit Values Unit Conditions Min. Max. -0.3 5.5 V – 6.2 V t < 10s2) 5.5 V – 6.2 V t < 10s1) -0.3 10 V IFX91041EJV50; IFX91041EJV33 -0.3 5.5 V IFX91041EJV VBUO VBUO V - 0.3 + 5.5 VBUO VEN VVS -2.0 VVS + 0.3 V -40 45 V -0.3 45 V Tj Tstg -40 150 °C – -55 150 °C – VESD -2 2 kV HBM 3) Voltages 4.1.1 4.1.2 Synchronization Input Compensation Input VSYNC VCOMP -0.3 4.1.3 4.1.4 Feedback Input VFB 4.1.5 4.1.6 Buck Driver Supply Input 4.1.7 Buck Switch Output 4.1.8 Enable Input 4.1.9 Supply Voltage Input VBDS Temperatures 4.1.10 Junction Temperature 4.1.11 Storage Temperature ESD Susceptibility 4.1.12 ESD Resistivity 1) Not subject to production test, specified by design. 2) Exposure to those absolute maximum ratings for extended periods of time (t > 10s) may affect device reliability 3) ESD susceptibility HBM according to EIA/JESD 22-A 114B (1.5kΩ,100pF). Note: Stresses above the ones listed here may cause permanent damage to the device. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Note: Integrated protection functions are designed to prevent IC destruction under fault conditions described in the data sheet. Fault conditions are considered as “outside” normal operating range. Protection functions are not designed for continuous repetitive operation. Data Sheet 5 Rev. 1.1, 2011-07-08 IFX91041 General Product Characteristics 4.2 Functional Range Pos. Parameter Symbol 4.2.1 Supply Voltage 4.2.2 Output Voltage adjust range 4.2.3 Buck inductor 4.2.4 Buck capacitor 4.2.5 Buck capacitor ESR 4.2.6 Junction Temperature VS VCC LBU CBU1 ESRBU1 Tj Limit Values Unit Conditions Min. Max. 4.75 45 V – 0.60 16 V IFX91041EJV 18 56 µH – 33 120 µF – – 0.3 Ω – 1) -40 125 °C – 1) See section ““Application Information” on Page 12” for loop compensation requirements. Note: Within the functional range the IC operates as described in the circuit description. The electrical characteristics are specified within the conditions given in the related electrical characteristics table. 4.3 Pos. Thermal Resistance Parameter Symbol 1) 4.3.1 Junction to Case 4.3.2 Junction to ambient1) RthJC RthJA Limit Values Unit Conditions Min. Typ. Max. – – 12 K/W – – 52 – K/W 2) 1) Not subject to production test, specified by design. 2) According to Jedec JESD52-1,-5,-7 at natural convection on 2s2p FR4 PCB for 1W power dissipation. PCB 76.2x114.3x1.5mm3 with 2 inner copper layers of 70µm thickness. Thermal via array conected to the first inner copper layer under the exposed pad. Data Sheet 6 Rev. 1.1, 2011-07-08 IFX91041 Buck Regulator 5 Buck Regulator 5.1 Description The gate of the power switch is driven by the external capacitor connected to pin BDS (Buck Driver Supply) using the bootstrap principle. An integrated under voltage lockout function supervising the ’bootstrap’ capacitor voltage ensures that the device is always driven with a sufficient bootstrap voltage in order to prevent from extensive heat up of the power transistor. An integrated charge pump supports the gate drive in case of low input supply voltage, small differential voltage between input supply and output voltage at low current and during startup. In order to minimize emission, the charge pump is switched off if the input voltage is sufficient for supplying the bootstrap. The soft start function generates a defined ramp of the output voltage during the first 0.5 ms (typ.) after device initialization. The device initialization is triggered either by the EN voltage level crossing the turn-on threshold, rising supply voltage (during EN=H), and also when the device restarts a after thermal shutdown. The ramp starts after the BDS external capacitor is charged. The regulation scheme uses a voltage controlled pulse width modulation with feed forward path (the feed forward operates for supply voltages from 8.0V to 36V) which provides a fast line transient reaction. In order to maintain the output voltage regulation even under low duty cycle conditions (light load conditions down to ICC=0mA, high input voltage) a pulse skipping operation mode is implemented. Pulse skipping is also used for operation with low supply voltages, related to high duty cycles >92% In case of a lost connection to the pin FB , an internal pull-up current prevents from a uncontrolled rise of the output voltage (version IFX91041EJV only). COMP OC Comp. L when Overcurrent Error Amp. FB Soft start BDS PWM H when Comp. Error -Signal < Error -Signal Error -Ramp VRef Output Stage OFF when H L when Tj > 175 °C = OFF when H R & t V low Clock tr tf tr S S Ramp Vhigh H = INV Q OFF 1 Q H= ON Power D-MOS BUO & Q PWM-FF & Schmitt-Trigger 1 V max V min & Gate Driver Supply Gate Driver L when Output overvoltage Feedforward ΔV=k X VS Oscillator tr tf tr _ >1 R Ramp Generator SYNC Charge Pump NOR1 Error -Ramp 0.6 V VS = Q Error -FF NAND 2 & H when UV at V BDS t BDS UV Comp. = Figure 3 Data Sheet Block Diagram Buck Regulator 7 Rev. 1.1, 2011-07-08 IFX91041 Buck Regulator 5.2 Electrical Characteristics Electrical Characteristics: Buck Regulator VS = 6.0 V to 40 V, Tj = -40 °C to +125°C, all voltages with respect to ground (unless otherwise specified) Pos. 5.2.1 Parameter Output voltage Symbol VFB Limit Values Min. Typ. Max. 4.90 5.00 5.10 Unit Conditions V IFX91041EJV50; VVEN = VS 0.1A < ICC < 1.0A VFB 5.2.2 5.2.3 Output voltage 5.2.4 VFB 4.80 5.00 5.20 V 3.23 VFB 3.17 VFB 3.30 V V 0.588 0.60 0.612 V VFB 0.576 0.60 0.624 V ICC,MIN 0 – – mA 5.2.8 1 – – mA 5.2.9 1.5 Output voltage 5.2.6 5.2.7 Minimum output load requirement 3.30 3.37 3.43 5.2.5 IFX91041EJV50; VVEN = VS; mA 1mA < ICC < 1.8A IFX91041EJV33; VVEN = VS; 0.1A < ICC < 1.0A IFX91041EJV33; VVEN = VS; 1mA < ICC < 1.8A IFX91041EJV; VVEN = VS; FB connected to VCC; VS = 12V 0.1A < ICC < 1.0A IFX91041EJV; VVEN = VS; FB connected to VCC; VS = 12V 1mA < ICC < 1.8A IFX91041EJV501) IFX91041EJV331) IFX91041EJV VCC ?> 3V1) 5.2.10 5 mA IFX91041EJV VCC ?> 1.5V1) 5.2.11 10 – – mA IFX91041EJV VCC ?> =0.6V1) 5.2.12 FB input current IFB -1 -0.1 0 µA IFX91041EJV VFB = 0.6V 5.2.13 FB input current IFB – – 900 µA IFX91041EJV50, IFX91041EJV33 5.2.14 Power stage on-resistance – – 500 mΩ tested at 300 mA 5.2.15 Current transition rise/fall time – 50 – ns 5.2.16 Buck peak over current limit 2.2 – 3.6 A ICC=1 A 2) – 5.2.17 Bootstrap under voltage lockout, turn-off threshold Ron tr IBUOC VBDS,off – V Bootstrap voltage decreasing – mA VS = 12V; VBUO = VBDS = GND 5.2.18 Charge pump current Data Sheet VBUO – +3.3 ICP 2 8 – Rev. 1.1, 2011-07-08 IFX91041 Buck Regulator Electrical Characteristics: Buck Regulator VS = 6.0 V to 40 V, Tj = -40 °C to +125°C, all voltages with respect to ground (unless otherwise specified) Pos. Parameter Symbol Limit Values Unit Conditions Min. Typ. Max. VBDS VBUO Dmax tstart – – 5 V (VBDS - VBUO) increasing – – 100 % 3) 350 500 750 µs VFB rising from 5% to 95% of VFB,nom 5.2.19 Charge pump switch-off threshold 5.2.20 Maximum duty cycle 5.2.21 Soft start ramp 5.2.22 Input under voltage shutdown threshold VS,off 3.75 – – V VS decreasing 5.2.23 Input voltage startup threshold – – 4.75 V VS increasing 5.2.24 Input under voltage shutdown hysteresis VS,on VS,hyst 150 – – mV – 1) Not subject to production test, application related parameter 2) Not subject to production test; specified by design. 3) Consider “Chapter 4.2, Functional Range” Data Sheet 9 Rev. 1.1, 2011-07-08 IFX91041 Module Enable and Thermal Shutdown 6 Module Enable and Thermal Shutdown 6.1 Description With the enable pin the device can be set in off-state reducing the current consumption to less than 2µA. The enable function features an integrated pull down resistor which ensures that the IC is shut down and the power switch is off in case the pin EN is left open. The integrated thermal shutdown function turns the power switch off in case of overtemperature. The typ. junction shutdown temperature is 175°C, with a min. of 160°C. After cooling down the IC will automatically restart operation. The thermal shutdown is an integrated protection function designed to prevent IC destruction when operating under fault conditions. It should not be used for normal operation. 6.2 Electrical Characteristics Module Enable, Bias and Thermal Shutdown Electrical Characteristics: Enable, Bias and Thermal Shutdown VS = 6.0 V to 40 V, Tj = -40 °C to +125°C, all voltages with respect to ground (unless otherwise specified) Pos. Parameter Symbol Limit Values Min. Typ. Max. Unit Conditions VEN = 0.8V; Tj < 105°C; VS = 16V VEN = 5.0V; ICC = 0mA; VS = 16V FB connected to VOUT VEN = 5.0V; ICC = 1.8A; VS = 16V FB connected to VOUT1) 6.2.1 Current Consumption, shut down mode Iq,OFF – 0.1 2 µA 6.2.2 Current Consumption, active mode Iq,ON – – 7 mA 6.2.3 Current Consumption, active mode Iq,ON – – 10 mA 6.2.4 VEN,lo VEN,hi Enable hysteresis VEN,HY Enable high input current IEN,hi Enable low input current IEN,lo Over temperature shutdown Tj,sd Over temperature shutdown Tj,sd_hyst 6.2.5 6.2.6 6.2.7 6.2.8 6.2.9 6.2.10 Enable high signal valid 3.0 – – V – Enable low signal valid – – 0.8 V – 50 200 400 mV 1) – – 30 µA – 0.1 1 µA VEN = 16V VEN = 0.5V 160 175 190 °C 1) – 15 – K 1) hysteresis 1) Specified by design. Not subject to production test. Data Sheet 10 Rev. 1.1, 2011-07-08 IFX91041 Module Oscillator 7 Module Oscillator 7.1 Description The oscillator turns on the power switch with a constant frequency while the buck regulating circuit turns the power transistor off in every cycle with an appropriate time gap depending on the output and input voltage. The internal sawtooth signal used for the PWM generation has an amplitude proportional to the input supply voltage (feedforward). The turn-on frequency can optionally be set externally via the ’SYNC’ pin using a TTL compatible input signal. In this case the synchronization of the PWM-on signal refers to the falling edge of the ’SYNC’-pin input signal. In case the synchronization to an external clock signal is not needed the ’SYNC’ pin should be connected to GND. Leaving pin SYNC open or short-circuiting it to GND leads to normal operation with the internal switching frequency. 7.2 Electrical Characteristics Module Oscillator Electrical Characteristics: Buck Regulator VS = 6.0 V to 40 V, Tj = -40 °C to +125°C, all voltages with respect to ground (unless otherwise specified) Pos. Parameter Symbol 7.2.1 Oscillator frequency 7.2.2 Synchronization capture range 7.2.3 SYNC signal high level valid 7.2.4 SYNC signal low level valid 7.2.5 SYNC input internal pull-down fosc fsync VSYNC,hi VSYNC,lo RSYNC Limit Values Unit Conditions VSYNC = 0V Min. Typ. Max. 330 370 420 kHz 530 kHz 200 V 1) 0.8 V 1) 1.4 MΩ VSYNC = 5V 2.9 0.60 1.0 1) Synchronization of PWM-on signal to falling edge. Data Sheet 11 Rev. 1.1, 2011-07-08 IFX91041 Application Information 8 Application Information Note: The following information is given as a hint for the implementation of the device only and shall not be regarded as a description or warranty of a certain functionality, condition or quality of the device. 8.1 Frequency Compensation The stability of the output voltage can be achieved with a simple RC connected between pin COMP and GND. The standard configuration using the swiching frequency of the internal oscillator is a ceramic capacitor CCOMP = 22nF and RCOMP = 22kΩ. By slight modifications to the compensation network the stability can be optimized for different application needs, such as varying switching frequency (using the sychronizing function), different types of buck capacitor (ceramic or tantalum) etc. The compensation network is essential for control loop stability. Leaving pin COMP open might lead to instable operation. 8.2 Compensating a tantalum buck capacitor CBU1 The TLE control loop is optimized for ceramic buck capacitors CBU. In order to maintain stability also for tantalum capacitors with ESR up to 300mΩ, an additional compensation capacitance CCOMP2 at pin COMP to GND is required. It’s value calculates: CCOMP2 = CBU * ESR(CBU) / RCOMP , whereas CCOMP2 needs to stay below 5nF. Application _C-COMP2.vsd COMP 3 IFX91041 CCOMP CCOMP2 2 RCOMP GND Figure 4 High-ESR buck capacitor compensation 8.3 Catch Diode In order to minimize losses and for fast recovery, a schottky catch diode is required. Disconnecting the catch diode during operation might lead to destruction of the IC. Data Sheet 12 Rev. 1.1, 2011-07-08 IFX91041 Application Information 8.4 IFX91041EJV50, IFX91041EJV33 with fixed Output Voltage LI 22…47µH D1 VBatt Ignition Key Terminal 15 7 EN 8 VS Enable Charge Pump Over Temperature Shutdown 5 BDS Feedforward COMP 3 CBOT 220nF Buck Converter 6 BUO DBU CCOMP SYNC 1 Oscillator 4 FB LBU VOUT 47µH CBU1 CBU2 100µF 220nF RCOMP Bandgap Reference Soft start ramp generator IFX91041EJV50 IFX91041EJV33 2 Figure 5 GND Application Diagram IFX91041EJV50 or IFX91041EJV33 Note: This is a very simplified example of an application circuit. The function must be verified in the real application Data Sheet 13 Rev. 1.1, 2011-07-08 IFX91041 Application Information 8.5 Adjustable Output Voltage Device LI 22…47µH D1 VBatt Ignition Key Terminal 15 7 EN 8 Biasing & Enable VS Charge Pump Over Temperature Shutdown 5 BDS Feedforward COMP 3 CBOT Buck Converter 220nF 6 BUO DBU CCOMP SYNC 1 Oscillator LBU VOUT 47µH R1 4 FB RCOMP Bandgap Reference Soft start ramp generator CFB CBU1 CBU2 100µF 220nF R2 IFX91041EJV 2 Figure 6 GND Application Diagram IFX91041EJV Note: This is a very simplified example of an application circuit. The function must be verified in the real application The output voltage of the IFX91041EJV can be programmed by a voltage divider connected to the feedback pin FB. The divider cross current should be 300 µA at minimum, therefore the maximum R2 calculates: R2 ≤ VFB / IR2 --> R2 ≤ 0.6V / 300 µA = 2 kΩ For the desired output voltage level VCC, R1 calculates then (neglecting the small FB input current): V CC ⎞ R 1 = R 2 ⎛ ---------–1 . ⎝V ⎠ FB Add a 0.5 nF capacitor close to FB pin. Data Sheet 14 Rev. 1.1, 2011-07-08 IFX91041 Package Outlines 9 Package Outlines 0.35 x 45˚ 1.27 0.41±0.09 2) 0.2 M 0.08 C Seating Plane C A-B D 8x 0˚...8˚ 0.64 ±0.25 D 1 5 1 6 ±0.2 0.2 M D 8x Bottom View 3 ±0.1 A 8 0.19 +0.06 8˚ MAX. 8˚ MAX. C 0.1 C D 2x 4 8 4 5 2.65 ±0.1 0˚...8˚ 1.7 MAX. Stand Off (1.45) 0.2 +0 -0.1 8˚ MAX. 0.1+0 -0.1 3.9 ±0.11) B 4.9 ±0.11) 0.1 C A-B 2x Index Marking 1) Does not include plastic or metal protrusion of 0.15 max. per side 2) Lead width can be 0.61 max. in dambar area 3) JEDEC reference MS-012 variation BA Figure 7 GPS01206 Outline PG-DSO-8-27 Green Product (RoHS compliant) To meet the world-wide customer requirements for environmentally friendly products and to be compliant with government regulations the device is available as a green product. Green products are RoHS-Compliant (i.e Pb-free finish on leads and suitable for Pb-free soldering according to IPC/JEDEC J-STD-020). For further package information, please visit our website: http://www.infineon.com/packages. Data Sheet 15 Dimensions in mm Rev. 1.1, 2011-07-08 IFX91041 Revision History 10 Rev.1.1 Revision History 2011-07-08 Adjustment of Junction Temperature Range in (4.2.6) “Functional Range” on Page 6 to the conditions used in the “Electrical Characteristics” on Page 8 ff (-40°C to 125°C) Rev.1.02 2010-02-23 Editorial change Rev.1.01 2009-10-19 Overview page: Inserted reference statement to TLE/TLF series. Rev.1.0 2009-05-04 Final data sheet Data Sheet 16 Rev. 1.1, 2011-07-08 Edition 2011-07-08 Published by Infineon Technologies AG 81726 Munich, Germany © 2011 Infineon Technologies AG All Rights Reserved. Legal Disclaimer The information given in this document shall in no event be regarded as a guarantee of conditions or characteristics. With respect to any examples or hints given herein, any typical values stated herein and/or any information regarding the application of the device, Infineon Technologies hereby disclaims any and all warranties and liabilities of any kind, including without limitation, warranties of non-infringement of intellectual property rights of any third party. Information For further information on technology, delivery terms and conditions and prices, please contact the nearest Infineon Technologies Office (www.infineon.com). Warnings Due to technical requirements, components may contain dangerous substances. For information on the types in question, please contact the nearest Infineon Technologies Office. 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