MIC4103

MIC4103 MICREL | Alldatasheet

Document overview

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Technical content

Features

• Asymmetrical, low impedance outputs drive 1000pF load with 10ns rise times and 6ns fall times
• Bootstrap supply max voltage to 118V DC
• Supply voltage up to 16V
• Drives high- and low-side N-Channel MOSFETs with independent inputs
• CMOS input thresholds (MIC4103)
• TTL input thresholds (MIC4104)
• On-chip bootstrap diode
• Fast 24ns propagation times
• Low power consumption
• Supply under-voltage protection
• Typical 2.5 Ω pull up and 1.25Ω pull down output driver resistance
• –40°C to +125°C junction temperature range

Applications

• High voltage buck converters
• Full- and half-bridge power topologies
• Active clamp forward converter
• Two switch forward topologies
• Interface to digital controllers Typical Application 100V Buck Regulator Solution

October 2007 2 M9999-100107-B

Ordering Information

Part Number Input Junction Temp. Range Package MIC4103YM CMOS –40° to +125°C 8-Pin SOIC MIC4104YM TTL –40° to +125°C 8-Pin SOIC MIC4103YML (coming soon) CMOS –40° to +125°C 8-Pin 3x3 MLF ® MIC4104YML (coming soon) TTL –40° to +125°C 8-Pin 3x3 MLF ® Pin Configuration 8-Pin SOIC (M) 8-Pin 3mm × 3mm MLF® (ML) Pin Description Pin Number Pin Name Pin Function 1 VDD Positive Supply to lower gate drivers. Decouple this pin to VSS (Pin 7). Bootstrap diode connected to HB (pin 2). 2 HB High-Side Bootstrap supply. External bootstrap capacitor is required. Connect positive side of bootstrap capacitor to this pin. Bootstrap diode is on-chip. 3 HO High-Side Output. Connect to gate of High-Side power MOSFET. 4 HS High-Side Source connection. Connect to source of High-Side power MOSFET. Connect negative side of bootstrap capacitor to this pin. 5 HI High-Side input. 6 LI Low-Side input. 7 VSS Chip negative supply, generally will be ground. 8 LO Low-Side Output. Connect to gate of Low-Side power MOSFET.

October 2007 3 M9999-100107-B Absolute Maximum Ratings(1) Operating Ratings(2) Junction Thermal Resistance Electrical Characteristics(4) VDD = VHB = 12V; VSS = VHS = 0V; No load on LO or HO; TA = 25°C; unless noted. Bold values indicate –40°C< TJ < +125°C. Symbol Parameter Condition Min Typ Max Units Supply Current IDD V DD Quiescent Current LI = HI = 0V 40 150 200 µA IDDO V DD Operating Current f = 500kHz 3.0 4.0 mA IHB Total HB Quiescent Current LI = HI = 0V 25 150 200 µA IHBO Total HB Operating Current f = 500kHz 1.5 2.5 3 mA IHBS HB to V SS Current, Quiescent V HS = VHB = 110V 0.05 1 30 µA Input Pins: MIC4103 (CMOS Input ) VIL Low Level Input Voltage Threshold 5.3 V VIH High Level Input Voltage Threshold 5.7 7 8 V VIHYS Input Voltage Hysteresis 0.4 V RI Input Pulldown Resistance 100 200 500 kΩ Input Pins: MIC4104 (TTL Input ) VIL Low Level Input Voltage Threshold 0.8 1.5 V VIH High Level Input Voltage Threshold 1.5 2.2 V RI Input Pulldown Resistance 100 200 500 kΩ Under Voltage Protection VDDR V DD Rising Threshold 6.5 7.4 8.0 V VDDH V DD Threshold Hysteresis 0.5 V VHBR HB Rising Threshold 6.0 7.0 8.0 V VHBH HB Threshold Hysteresis 0.4 V

October 2007 4 M9999-100107-B Symbol Parameter Condition Min Typ Max Units Bootstrap Diode VDL Low-Current Forward Voltage I VDD-HB = 100µA 0.4 0.55 0.70 V VDH High-Current Forward Voltage I VDD-HB = 100mA 0.7 0.8 1.0 V RD Dynamic Resistance I VDD-HB = 100mA 1.0 1.5 2.0 Ω LO Gate Driver VOLL Low Level Output Voltage I LO = 160mA 0.18 0.3 0.4 V VOHL High Level Output Voltage I LO = -100mA, VOHL = VDD - VLO 0.25 0.3 0.45 V IOHL Peak Sink Current V LO = 0V 3 A IOLL Peak Source Current V LO = 12V 2 A HO Gate Driver VOLH Low Level Output Voltage I HO = 160mA 0.22 0.3 0.4 V VOHH High Level Output Voltage I HO = -100mA, VOHH = VHB – VHO 0.25 0.3 0.45 V IOHH Peak Sink Current V HO = 0V 3 A IOLH Peak Source Current V HO = 12V 2 A Switching Specifications tLPHL Lower Turn-Off Propagation Delay (LI Falling to LO Falling) (MIC4103) 24 45 ns tHPHL Upper Turn-Off Propagation Delay (HI Falling to HO Falling) (MIC4103) 24 45 ns tLPLH Lower Turn-On Propagation Delay (LI Rising to LO Rising) (MIC4103) 24 45 ns tHPLH Upper Turn-On Propagation Delay (HI Rising to HO Rising) (MIC4103) 24 45 ns tLPHL Lower Turn-Off Propagation Delay (LI Falling to LO Falling) (MIC4104) 24 45 ns tHPHL Upper Turn-Off Propagation Delay (HI Falling to HO Falling) (MIC4104) 24 45 ns tLPLH Lower Turn-On Propagation Delay (LI Rising to LO Rising) (MIC4104) 24 45 ns tHPLH Upper Turn-On Propagation Delay (HI Rising to HO Rising) (MIC4104) 24 45 ns tMON Delay Matching: Lower Turn-On and Upper Turn-Off 3 8 10 ns tMOFF Delay Matching: Lower Turn-Off and Upper Turn-On 3 8 10 ns tRC Output Rise Time C L = 1000pF 10 ns tFC Output Fall Time C L = 1000pF 6 ns

October 2007 5 M9999-100107-B Symbol Parameter Condition Min Typ Max Units Switching Specifications (cont.) tR Output Rise Time (3V to 9V) C L = 0.1µF 0.4 0.6 0.8 µs tF Output Fall Time (3V to 9V) C L = 0.1µF 0.2 0.3 0.4 µs tPW Minimum Input Pulse Width that Changes the Output Note 6 50 ns tBS Bootstrap Diode Turn-On or Turn-Off Time 10 ns Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 4. Specification for packaged product only. 5. All voltages relative to pin 7, VSS unless otherwise specified 6. Guaranteed by design. Not production tested.

October 2007 6 M9999-100107-B Timing Diagrams Note: All propagation delays are measured from the 50% voltage level.

October 2007 7 M9999-100107-B Typical Characteristics

October 2007 8 M9999-100107-B Typical Characteristics

Figure 1. MIC4103/4 Functional Block Diagram block diagram of the MIC4103 is shown in Figure 1. causing chatter during turn-on.

October 2007 11 M9999-100107-B

Application Information

Power Dissipation Considerations Power dissipation in the driver can be separated into three areas:

• Internal diode dissipation in the bootstrap circuit
• Internal driver dissipation
• Quiescent current dissipation used to supply the internal logic and control functions. Bootstrap Circuit Power Dissipation Power dissipation of the internal bootstrap diode primarily comes from the average charging current of the C B capacitor times the forward voltage drop of the diode. Secondary sources of diode power dissipation are the reverse leakage current and reverse recovery effects of the diode. The average current drawn by repeated charging of the high-side MOSFET is calculated by: frequency switching drive gate Vat ChargeGateTotalQ:where HBgate S SgateAVEF f fQI The average power dissipated by the forward voltage drop of the diode equals: drop voltage forward DiodeV:where F ×= FAVEFfwd VIPdiode The value of V F should be taken at the peak current through the diode, however, this current is difficult to calculate because of differences in source impedances. The peak current can either be measured or the value of V F at the average current can be used and will yield a good approximation of diode power dissipation. The reverse leakage current of the internal bootstrap diode is typically 11µA at a reve rse voltage of 100V and 125°C. Power dissipation due to reverse leakage is typically much less than 1mW and can be ignored. Reverse recovery time is the time required for the injected minority carriers to be swept away from the depletion region during turn-off of the diode. Power dissipation due to reverse recovery can be calculated by computing the average reverse current due to reverse recovery charge times the reverse voltage acro ss the diode. The average reverse current and power dissipation due to reverse recovery can be estimated by: TimeRecovery Reverset CurrentRecovery Reverse PeakI:where 5.0 rr RRM ×××= REVAVERRRR SrrRRMAVERR VIPdiode ftII The total diode power dissipation is: RRfwdtotal PdiodePdiodePdiode += An optional external bootstrap diode may be used instead of the internal diode (Figure 6). An external diode may be useful if high gate charge MOSFETs are being driven and the power dissipation of the internal diode is contributing to excessive die temperatures. The voltage drop of the external diode must be less t han the internal diode for this option to work. The reverse voltage across the diode will be equal to the input voltage minus the VDD supply voltage. A 100V Schottky diode will work for most 72Vinput telecom applications. The above equations can be used to calculate power dissipation in the external diode, however, if the external diode has si gnificant reverse leakage current, the power dissipated in that diode due to reverse leakage can be calculated as: supply power the offrequency switching fs /t CycleDuty D VoltageReverse Diode V T and Vatflow current ReverseI:where )1( ON REV JREVR −××= S REVRREV f DVIPdiode The on-time is the time the high-side switch is conducting. In most power supply topologies, the diode is reverse biased during the switching cycle off-time. HS HB HO Vdd CB LO Level shiftHI LI Vss Vin

Figure 6. Optional Bootstrap Diode

October 2007 13 M9999-100107-B Total power dissipation and Thermal Considerations Total power dissipation in the MIC4103 or MIC4104 is equal to the power dissipation caused by driving the external MOSFETs, the supply current, and the internal bootstrap diode. totaldrivetotal PdiodePdissPdissPdiss ++= supply The die temperature may be calculated once the total power dissipation is known. JAtotalAJ PdissTT θ×+= C/W)( air ambient to junction from resistance thermal the is θ MIC4103/4 the of ndissipatio power the is Pdiss C)( etemperatur junction the is T etemperatur ambient maximum the is T JC total J A where Propagation Delay and Delay Matching and other Timing Considerations Propagation delay and signal timing is an important consideration in a high performance power supply. The MIC4103 is designed not only to minimize propagation delay but to minimize the mi smatch in delay between the high-side and low-side drivers. Fast propagation delay between the input and output drive waveform is desirable. It improves overcurrent protection by decreasing the response time between the control signal and the MOSFET gate drive. Minimizing propagation delay also minimizes phase shift errors in power supplies with wide bandwidth control loops. Many power supply topologies use two switching MOSFETs operating 180º out of phase from each other. These MOSFETs must not be on at the same time or a short circuit will occur, causing high peak currents and higher power dissipation in the MOSFETs. The MIC4103 and MIC4104 output gate drivers are not designed with anti-shoot-through protection ci rcuitry. The output drive signals simply follow the i nputs. The power supply design must include timing delays (dead-time) between the input signals to prevent shoot-through. The MIC4103 & MIC4104 drivers specify delay matching between the two drivers to help improve power supply performance by reducing the amount of dead -time required between the input signals. Care must be taken to insure the input signal pulse width is greater than the minimum specified pulse width. An input signal that is less t han the minimum pulse width may result in no output pulse or an output pulse whose width is significantly less than the input. The maximum duty cycle (ratio of high side on-time to switching period) is controlled by the minimum pulse width of the low side and by t he time required for the C B capacitor to charge during the off-time. Adequate time must be allowed for the C B capacitor to charge up before the high-side driver is turned on. Decoupling and Bootstrap Capacitor Selection Decoupling capacitors are required for both the low side (Vdd) and high side (HB) supply pins. These capacitors supply the charge necessary to drive the external MOSFETs as well as minimize the voltage ripple on these pins. The capacitor from HB to HS serves double duty by providing decoupling for the high-side circuitry as well as providing current to the high-side circuit while the high-side external MOSFET is on. Ceramic capacitors are recommended because of their low impedance and small size. Z5U type ceramic capacitor dielectrics are not recommended due to the large change in capacitance over temperature and voltage. A mi nimum value of 0.1uf is required for each of the capacitors, regardless of the MOSFETs being driven. Larger MOSFETs may require larger capacitance values for proper operation. The voltage rating of the capacitors depends on the supply voltage, ambient temperatur e, and the voltage derating used for reliability. 25V rated X5R or X7R ceramic capacitors are recommended for most applications. The minimum capacitance value should be increased if low voltage capacitors are used since even good quality dielectric capacitors, such as X5R, will lose 40% to 70% of their capacitance value at the rated voltage. Placement of the decoupling c apacitors is critical. The bypass capacitor for Vdd should be placed as close as possible between the Vdd and Vss pins. The bootstrap capacitor (C B) for the HB supply pin must be located as close as possible between the HB and HS pins. The trace connections must be short, wide, and direct. The use of a ground plane to minimize connection impedance is recommended. Refer to the section on layout and component placement for more information. The voltage on the bootstrap capacitor drops each time it delivers charge to turn on the MOSFET. The voltage drop depends on the gate charge required by the MOSFET. Most MOSFET specifications specify gate charge vs. Vgs voltage. Based on this information and a recommended HB of less than 0.1V, the minimum value of bootstrap capacitance is calculated as: pin HB the at drop Voltage ∆ VatChargeGateTotalQ:where HB HBgate HB gate B V Q C The decoupling capacitor for the Vdd input may be calculated with the same formula, however, the two capacitors are usually equal in value. Grounding, Component Placement, and Circuit Layout Nanosecond switching speeds and ampere peak currents

October 2007 16 M9999-100107-B

Package Information

8-Pin SOIC (M) 8-Pin MLF® (ML)

October 2007 17 M9999-100107-B MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com The information furnished by Micrel in this data sheet is belie ved to be accurate and reliable. However, no responsibility is a ssumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life suppo rt devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significan t injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2006 Micrel, Incorporated.