Si9145 Vishay Siliconix Low-Voltage Switchmode Controller FEATURES D D D D D D 2.7-V to 7-V Input Operating Range Voltage-Mode PWM Control High-Speed, Source-Sink Output Drive (200 mA) Internal Oscillator (up to 2 MHz) Standby Mode 0−100% Controllable Maximum Duty-Cycle DESCRIPTION The Si9145 switchmode controller IC is ideally suited for high efficiency dc/dc converters in low input voltage systems. Operation is guaranteed down to 2.7 V, with a minimum start-up voltage of 3.0 V making the Si9145 ideal for use with NiCd, NMH, and lithium ion battery packs. A mode select pin allows the output driver polarity to be programmed allowing the device to function as a step-up or step-down converter. Supply current in normal operation is typically 1.1 mA and 250 mA in standby mode. The Si9145 implements conventional voltage mode control. The maximum duty cycle in boost mode can be limited by voltage on DMAX/SS pin. Frequency can be externally programmed by selection of ROSC and COSC. Features include a precision bandgap reference, a wide bandwidth error amplifier, a 2-MHz oscillator, an input voltage monitor with standby mode and a 200-mA output driver. The Si9145 is available in both standard and lead (Pb)-free 16-pin SOIC and TSSOP packages and is specified over the industrial temperature range (−25_C to 85_C). FUNCTIONAL BLOCK DIAGRAM 1.5-V Reference Generator VDD UVLO UVLOSET VREF Temp Sense VUVLO S OTS ENABLE R MODE SELECT DMAX/SS COMP Error Amp NI + FB − COSC ROSC VS + Logic Control − Driver OUTPUT PGND + − GND Oscillator Pentiumt is a trademark of Intel Corporation. PowerPCt is a trademark of IBM. Document Number: 70021 S-40710—Rev. K, 19-Apr-04 www.vishay.com 1 Si9145 Vishay Siliconix ABSOLUTE MAXIMUM RATINGS Voltages Referenced to GND. VDD, VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 V PGND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "0.3 V VDD to VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V Linear Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to VDD to +0.3 V Logic Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −0.3 V to VDD to +0.3 V Continuous Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 mA Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . −65 to 125_C Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150_C Power Dissipation (Package)a 16-Pin SOIC (Y Suffix)b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 mW 16-Pin TSSOP (Q Suffix)c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925 mW Thermal Impedance (QJA) 16-Pin SOIC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140_C/W 16-Pin TSSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135_C/W Notes a. Device mounted with all leads soldered or welded to PC board. b. Derate 7.2 mW/_C above 25_C. c. Derate 7.4 mW/_C above 25_C. RECOMMENDED OPERATING RANGE Voltages Referenced to GND. VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 V to 7 V COSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 pF to 200 pF VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7 V to 7 V Linear Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to VDD fOSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 kHz to 2 MHz Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 to VDD ROSC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 kW to 250 kW VREF Load Resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >150 kW SPECIFICATIONS Test Conditions Unless Otherwise Specifieda Parameter Symbol 2.7 V v VDD v 7 V, VDD = VS GND = PGND Limits B Suffix − 25 to 85_C Minb Typ Maxb Unit Reference Output Voltage VREF IREF = −10 mA 1.455 TA = 25_C 1.477 1.545 1.50 1.523 1.0 1.15 V Oscillator Maximum Frequencyc Accuracy ROSC Voltage Minimum Start-Up Voltage fMAX fOSC 100% DMAX/SS VDMAX 100% Temperature Stabilityc www.vishay.com 2 TA = 25_C 2.0 0.85 IDMAX Df/f MHz 1.0 VDDOSC VDMAX 50% Voltage g Stabilityyc VCC = 3.0 V COSC = 100 pF, ROSC = 6.98 kW VROSC 50% DMAX/SS DMAX/SS Input Current VCC = 3.0 V, COSC = 47 pF, ROSC = 5.0 kW 3.0 V 1.30 MODE SELECT = VDD 1.58 DMAX = 0 to VDD −100 100 2.7 V v VDD v 7 V, Ref to 4.8 V −16 16 −8 8 −7 7 2.7 V v VDD v 4.2 V, Ref to 3.5 V 3.8 V v VDD v 5.6 V, Ref to 4.7 V Referenced to 25_C TA = 25_C nA % "5 Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Si9145 Vishay Siliconix SPECIFICATIONS Test Conditions Unless Otherwise Specifieda Parameter Symbol Limits B Suffix − 25 to 85_C 2.7 V v VDD v 7 V, VDD = VS GND = PGND Minb VNI = VREF , VFB = 1.0 V −1.0 Typ Maxb Unit 1.0 mA 15 mV Error Amplifier (COSC = GND, OSC DISABLED) Input Bias Current IFB Open Loop Voltage Gain AVOL Offset Voltage VOS Unity Gain Bandwidthc BW Output Current IEA Power Supply Rejectionc VNI = VREF 47 55 −15 0 dB 10 Source (VFB = 1 V, NI = VREF) Sink (VFB = 2 V, NI = VREF) −2.0 0.4 PSRR 2.7 V < VDD < 7.0 V VUVLOHL UVLOSET High to Low VUVLOLH UVLOSET Low to High Hysterisis VHYS VUVLOLH − VUVLOHL UVLO Input Current IUVLO VUVLO = 0 to VDD −100 Output High Voltage VOH VDD = 2.7 V, IOUT = −10 mA 2.55 Output Low Voltage VOL VDD = 2.7 V, IOUT = 10 mA Peak Output Current ISOURCE VDD = 2.7 V, VOUT = 0 V Peak Output Current ISINK VDD = 2.7 V, VOUT = 2.7 V ENABLE Delay to Output tdEN ENABLE Rising to OUTPUT ENABLE Logic Low VENL ENABLE Logic High VENH MHz −1.0 0.8 60 mA dB UVLOSET Voltage Monitor Under Voltage Lockout 0.85 1.0 1.15 1.2 200 V mV 100 nA Output 150 2.60 0.06 0.15 −180 −130 200 V mA Logic ENABLE Input Current IEN MODE SELECT Logic Low VMODEL MODE SELECT Logic High VMODEH MODE SELECT Input Current IMODE 1.5 ns 0.2 VDD 0.8 VDD ENABLE = 0 to VDD −1.0 1.0 0.2 VDD 0.8 VDD MODE SELECT = 0 to VDD −1.0 1.0 V mA V mA Over Temperature Sense Trip Point TTRIP Output Low Voltage VOTSL VDD = 2.7 V, IOUT = 1 mA 150 Output High Voltage VOTSH VDD = 2.7 V, IOUT = −1 mA 0.06 2.55 _C 0.15 2.6 V Supply Supply Current − Normal Mode Supply Current − Standby Mode IDD VDD = 2.7 V, fOSC = 1 MHz, ROSC = 6.98 kW 1.1 1.5 VDD = 7 V, fOSC = 1 MHz, ROSC = 6.98 kW 1.6 2.3 ENABLE = Low 250 330 mA mA Notes a. CSTRAY < 5 pF on COSC. After Start-Up, VDD of w 3 V. b. The algebraic convention whereby the most negative value is a minimum and the most positive a maximum, is used in this data sheet. c. Guaranteed by design, not subject to production testing. Document Number: 70021 S-40710—Rev. K, 19-Apr-04 www.vishay.com 3 Si9145 Vishay Siliconix TYPICAL CHARACTERISTICS (25_C UNLESS NOTED) VREF vs. Supply Voltage 1.515 VREF vs. Temperature 1.515 VDD = 3.6 V 1.510 1.510 1.505 1.505 V REF (V) V REF (V) VREF with 10 mA Load 1.500 1.500 1.495 1.495 1.490 1.490 1.485 2 3 4 5 6 7 1.485 −25 8 0 25 VDD − Supply Voltage (V) VREF vs. Load Current 1.515 50 75 100 125 t − Temperature (_C) Error Amplifier Gain and Phase 80 60 1.510 0 Gain 40 Gain (dB) 2.7, 3.0, 3.6 V 1.500 7.0 V 5.0 V 1.495 Phase 20 −60 0 −90 −20 1.490 1.485 −120 −40 5 25 10 15 20 25 30 −150 0.0001 0.001 0.01 0.1 10 1 VREF − Sourcing Current (mA) f − Frequency (MHz) Supply Current vs.Supply Voltage and Output Load Supply Current vs. Switching Frequency and Output Load f = 1 MHz 25 20 15 900 pF 10 100 pF 5 CL = 2,200 pF 15 900 pF 10 100 pF 5 10 pF 10 pF 0 2 3 4 5 VDD − Supply Voltage (V) www.vishay.com 4 6 100 VDD = 3.6 V CL = 2,200 pF 20 Supply Current (mA) 0 Supply Current (mA) −30 Phase (deg) V REF (V) 1.505 7 0 0.5 1.0 1.5 2.0 Switching Frequency (MHz) Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Si9145 Vishay Siliconix TYPICAL CHARACTERISTICS (25_C UNLESS NOTED) Supply Current vs. Frequency and Supply Voltage 1.9 5 CL = 10 pF CL = 10 pF f = 1 MHz VDD = 7.0 V 1.7 4 5.0 V Normal Current (mA) Supply Current (mA) Supply Current vs. Supply Voltage and Temperature 3 2 1.3 25_C 1.1 3.0 V 0.2 TA = 85_C −25_C 3.6 V 1 0.0 1.5 0.4 0.6 2.7 V 0.8 0.9 2.5 1.0 3.5 f − Frequency (MHz) 100 260 80 Duty Cycle (%) Standby Current (m A) 270 TA = 85_C 25_C 240 6.5 7.5 Duty Cycle vs. DMAX/SS Voltage 60 40 −25_C 230 20 220 2 3 4 5 6 0 1.0 7 VDD − Supply Voltage (V) 1.1 1.2 1.3 1.4 1.5 1.6 DMAX/SS (V) Switching Frequency vs. Supply Voltage 1.20 Frequency vs. ROSC/COSC 10.00 ROSC = 6.98 kW COSC = 100 pF Switching Frequency (MHz) 1.15 Switching Frequency (MHz) 5.5 VDD − Supply Voltage (V) Standby Current vs. Supply Voltage and Temperature 250 4.5 1.10 1.05 1.00 1.00 4.99 kW 12.1 kW 24.9 kW 0.10 49.9 kW 100 kW 0.95 249 kW 0.90 0.01 2 3 4 5 VDD − Supply Voltage (V) Document Number: 70021 S-40710—Rev. K, 19-Apr-04 6 7 40 100 200 300 COSC − Capacitance (pF) www.vishay.com 5 Si9145 Vishay Siliconix TYPICAL CHARACTERISTICS (25_C UNLESS NOTED) Output Rise Time vs. Supply Voltage and Load 50 50 40 CL = 2,200 pF 40 CL = 2,200 pF Fall Time (nS) Output Rise Time (nS) Output Fall Time vs. Supply Voltage and Load 30 900 pF 20 100 pF 10 2 3 900 pF 20 10 10 pF 0 30 100 pF 0 4 5 6 7 2 3 VDD − Supply Voltage (V) 5 6 7 UVLO Hysteresis vs. Supply Voltage 250 230 UVLO Hysteresis (mV) 40 Output Delay (nS) 4 VDD − Supply Voltage (V) Enable Delay to Output 50 10 pF Mode Select = High 30 Mode Select = Low 20 210 190 170 10 150 2 3 4 5 6 7 VDD − Supply Voltage (V) 2 3 4 5 6 7 VDD − Supply Voltage (V) VREF vs. Bypass Capacitor 1.515 VDD = 3.6 V 1.510 V REF (V) 1.505 1.500 1.495 1.490 1.485 0 2 4 6 8 10 Capacitance (mF) www.vishay.com 6 Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Si9145 Vishay Siliconix TIMING WAVEFORMS Start-Up (UVLO) Normal (Duty Cycle Limit) Standby ENABLE MODE SELECT 1.2 V UVLOSET 1.0 V 1.0 V ROSC COSC ON OUTPUT OFF >1.5 V Set for 50% Max. DMAX/SS Figure 1. Si9145 Timing Diagram (MODE SELECT = High) Start-Up (UVLO) Normal (Duty Cycle Limit) Standby ENABLE MODE SELECT 1.2 V UVLOSET 1.0 V 1.0 V ROSC COSC OFF OUTPUT ON DMAX/SS Figure 2. Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Si9145 Timing Diagram (MODE SELECT = Low) www.vishay.com 7 Si9145 Vishay Siliconix PIN CONFIGURATIONS SOIC-16 VDD 1 16 VS MODE SELECT 2 15 OUTPUT DMAX/SS 3 14 PGND COMP 4 13 UVLOSET FB 5 12 ENABLE NI 6 11 OTS VREF 7 10 COSC GND 8 9 ROSC TSSOP-16 VDD 1 16 VS MODE SELECT 2 15 OUTPUT DMAX/SS 3 14 PGND COMP 4 13 UVLOSET FB 5 12 ENABLE OTS NI 6 11 VREF 7 10 COSC GND 8 9 ROSC Top View Top View ORDERING INFORMATION−SOIC-16 Part Number Si9145BY-T1 Si9145BY-T1—E3 Temperature Range −25_ 25_ to 85_C ORDERING INFORMATION−TSSOP-16 Part Number Si9145BQ-T1 Si9145BQ-T1—E3 Temperature Range −25_ 25_ to 85_C PIN DESCRIPTION Pin 1: VDD voltage at DMAX/SS between 1.0 V and 1.5 V, the maximum duty cycle is proportionally limited to this voltage. The positive power supply for all functional blocks except output driver. A bypass capacitor of 0.1 mF (minimum) is recommended. The addition of external components can implement a soft start function. Pin 4: COMP Pin 2: MODE SELECT This pin is used to enable maximum duty cycle limit and set output polarity of controller. When connected to VDD, the maximum duty cycle function is controlled by the DMAX/SS pin. The maximum duty cycle limit is usually used for forward, flyback, and boost converters. The output polarity is high when the PWM circuitry requires the external device to be turned on. When connected to GND, the maximum duty cycle is not limited (usually for buck converters driving a p-channel MOS). The output polarity is low when the PWM circuitry requires the external PMOS to be turned on. Pin 3: DMAX/SS DMAX/SS pin controls the maximum duty cycle achievable by the PWM circuitry when the MODE SELECT = VDD. When DMAX/SS is at less than 1.0 V (typical) the OUTPUT is held low (0% duty cycle). When DMAX/SS is at more than 1.5 V (typical), the PWM circuitry can achieve 100% duty cycle. With www.vishay.com 8 This pin is the output of the error amplifier. A compensation network is connected from this pin to the FB pin to stabilize the system. This pin drives one input of the internal pulse width modulation comparator. Pin 5: FB The inverting input of the error amplifier. External resistors are connected to this pin to set the regulated output voltage. The compensation network is also connected to this pin. Pin 6: NI The non-inverting input of the error amplifier. In normal operation it is externally connected to the VREF pin. Pin 7: VREF This pin supplies 1.5 V trimmed to "1.5%. The reference voltage is generated by a band-gap reference. Pin 8: GND Negative return for VDD. Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Si9145 Vishay Siliconix Pin 9: ROSC Pin 12: ENABLE This pin is the equivalent of a 1.0-V voltage source derived from the on-chip VREF . When a low T.C. resistor is externally connected from this pin to GND, a temperature independent current is generated internally. This current is used as the charging current source connected to the COSC pin. The current is internally multiplied by 2 and is used as the discharging current source connected to the COSC pin. Therefore, the external resistor is one of the factors that determine the oscillator frequency. A logic high on this pin allows normal operation. A logic low places the chip in the standby mode. In standby mode normal operation is disabled, supply current is reduced, the oscillator stops and the output is held high for MODE SELECT = low, and low for MODE SELECT = high. Pin 10: COSC An external capacitor is connected to this pin to set the oscillator frequency. Internal current sources alternately charge and discharge the external capacitor. The oscillator waveform is a symmetrical triangular type with a typical voltage swing between 1.0 V and 1.5 V. fOSC ] R 0.7 OSC < C OSC Pin 11: OTS This pin indicates an over-temperature condition on the device when the output is low. The output is latched low and is reset with the ENABLE pin going low then high, or by turning power off and on. Document Number: 70021 S-40710—Rev. K, 19-Apr-04 Pin 13: UVLOSET This pin will place the chip in the standby mode if the UVLOSET voltage drops below 1.2 V. Once the UVLOSET voltage exceeds 1.2 V, the chip operates normally. There is a built-in hysteresis of 200 mV. Pin 14: PGND The negative return for the VS supply. Pin 15: OUTPUT This CMOS push-pull output pin drives the external MOSFET and is capable of sinking 150 mA or sourcing 130 mA with VS equal to 2.7 V. Pin 16: VS The positive terminal of the power supply which powers the CMOS output driver. A bypass capacitor is required. www.vishay.com 9 Si9145 Vishay Siliconix APPLICATIONS L1 D1 VOUT VDD Q1 C1 C2 Si9145 2.7 V − 7 V 0V Figure 3. Non-Isolated Step Up Boost Converter for VOUT > VIN L1 Q1 VDD VOUT C1 C2 Si9145 2.7 V − 7 V D1 0V Figure 4. VDD Non-Isolated Step Down Buck Converter for VOUT < VIN Q1 C1 2.7 V − 7 V L1 Si9145 VOUT Q2 C2 0V Figure 5. www.vishay.com 10 Non-Isolated Synchronous Buck Converter for VOUT < VIN Document Number: 70021 S-40710—Rev. K, 19-Apr-04