KB3302EMS

KB3302 KINGBOR | Alldatasheet

Document overview

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Technical content

■ Up to 95% Efficiency ■ TDB uA No Load Current ■ 1000mA Output Current ■ 1.5V to 16V Input Voltage Range ■ Programmable switching frequency up to 2MHz ■ Output voltage up to 32V ■ Constant switching frequency current-mode control ■ 1.23V Reference Allows Low Output Voltages ■ Shutdown Mode Draws )10µA Supply Current ■ Low saturation voltage switch: 220mV at 2A ■ Overtemperature Protected,Soft-Start function ■ 8-Pin MSOP Packages ■ Flat screen LCD bias supplies ■ TFT bias supplies ■ XDSL power supplies ■ Medical equipment ■ Digital video cameras ■ Portables devices KB3302 Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052

APPLICATIONS

Figure 1. 1.2 M Hz All Ceramic Capacitor Single L i-ion Cell plications such as Boost, SEPIC and Flyback. is available in thermally enhanced 8-Pin MSOP packages.

(Note 1) Operating Temperature Range (Note 2) .. – 40°C to 85°C KB3302 Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 ABSOLUTE MAXIMUM RATINGS PACkAGE/ORDER INFORMATION

ELECTRICAL CHARACTERISTICS

10-LEAD (3mm × 3mm) PLASTIC DFN EXPOSED PAD IS PGND (PIN 11) MUST BE CONNECTED TO GND ORDER PART NUMBER DD PART MARKING TJMAX = 125°C, θJA = 45°C/W, θJC = 10°C/W KB3302DD TOP VIEW GND 1 SS ROSC VIN SW SW COMP FB SHDN GND GND TJMAX = 125°C, θJA = 45°C/W, θJC = 10°C/W TOP VIEW 8-LEAD PLASTIC MSOP EXPOSED PAD IS PGND MUST BE CONNECTED TO GND SSCOMP ROSCFB VINSHDN SWGND ORDER PART NUMBER EMS PART MARKING KB3302EMS Parameter Test Conditions Min Typ Max Unit Undervoltage Lockout Threshold 1.3 1.4 V Maximum Operating Voltage 16 V Feedback Voltage TA = 25°C 1.224 1.242 1.260 V -40°C < TA < 85°C 1.217 1.267 V Feedback Voltage Line Regulation 1.5V < VIN < 16V 0.01 % FB Pin Bias C urrent 40 80 nA Error Amplifier Transconductance 60 µΩ−1 Error Amplifier Open-Loop Gain 49 dB COMP Source Current V FB = 1.1V 5 µA COMP Sink Current V FB = 1.4V 5 µA VIN Quiescent Supply Current V SHDN = 1.5V, VCOMP = 0 ( Not Switching ) 1.1 1.6 mA VIN Supply Current in Shutdown V SHDN = 0 10 18 µA Switching Frequency 1.3 1.5 1.7 MHz Maximum Duty Cycle 85 90 % Minimum Duty Cycle 0% Switch Current Limit 2 2.8 A Switch Saturation Voltage I SW = 2A 220 350 mV Unless specified: VIN = 2V, SHDN = 1.5V, ROSC = 7.68kΩ, -40°C < TA = TJ < 85°C GND

2500 Units on Tape and Reel3000 Units on Tape and Reel

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 TYPICAL PERFORMANCE CHARACTERISTICS Unless specified: VIN = 2V, SHDN = 1.5V, ROSC = 7.68kΩ, -40°C < TA = TJ < 85°C Parameter Test Conditions Min Typ Max Unit Switch Leakage Current V SW = 5V 0.01 1 µA Shutdown Threshold Voltage 1.02 1.1 1.18 V Shutdown Pin Current VSHDN= 1.2V -4.6 µA VSHDN= 0 0 0.1 µA Soft-Start Charging Current V SS = 0.3V 1.5 µA Thermal Shutdown Temperature 160 °C Thermal Shutdown Hysteresis 10 °C Shutdown Pin Current vs Temperature -50 -25 0 25 50 75 100 125 Temperature (ºC) Current (µA) VIN = 2V VIN = 12V VSHDN = 1.25V Transconductance vs Temperature -50 -25 0 25 50 75 100 125 Temperature (ºC) Transconductance (µΩ VIN = 2V Soft-Start Charging Current vs Temperature 1.2 1.4 1.6 1.8 - 5 0 - 2 50 2 55 07 5 1 0 0 1 2 5 Temperature (ºC) Current (µA) VSS = 0.3V VIN Current vs SHDN Pin Voltage 0.02 0.04 0.06 0.08 0.1 SHDN Voltage (V) VIN Current (mA) 25ºC VIN = 2V VIN Current vs SHDN Pin Voltage 0.2 0.4 0.6 0.8 1.2 0 0.5 1 1.5 SHDN Voltage (V) VIN Current (mA) 125ºC-40ºC VIN = 2V -40ºC 125ºC

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 TYPICAL PERFORMANCE CHARACTERISTICS Feedback Voltage vs Temperature 1.15 1.2 1.25 1.3 -50 -25 0 25 50 75 100 125 Temperature (ºC) Feedback Voltage (V) Switch Current Limit vs Temperature 2.2 2.4 2.6 2.8 -50 -25 0 25 50 75 100 Temperature (ºC) Current Limit (A) ROSC vs Switching Frequency 100 Frequency (MHz) ROSC (KΩ) VIN = 2V 25ºC Switching Frequency vs Temperature 1.3 1.4 1.5 1.6 1.7 -50 -25 0 25 50 75 100 125 Temperature (ºC) Frequency (MHz) VIN = 12V VIN = 2V ROSC = 7.68KΩ VIN Quiescent Current vs Temperature 0.8 0.9 1.1 1.2 1.3 -50 -25 0 25 50 75 100 125 Temperature (ºC) VIN Current (mA) VIN = 16V VIN = 2V Not Switching VIN Current in Shutdown vs Input Voltage 0 5 10 15 20 Input Voltage (V) VIN Current (µA) 125ºC -40ºC VSHDN = 0 Shutdown Threshold vs Temperature 1.00 1.05 1.10 1.15 1.20 -50 -25 0 25 50 75 100 125 Temperature (ºC) Shutdown Threshold (V) VIN = 2V Minimum VIN vs Temperature 1.1 1.2 1.3 1.4 1.5 -50 -25 0 25 50 75 100 125 Temperature (ºC) Input Voltage (V) Switch Saturation Voltage vs Switch Current 100 200 300 400 0 0.5 1 1.5 2 2.5 3 Switch Current (A) VCESAT (mV) 85ºC 25ºC -40ºC

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 PIN FUNCTIONS Pin Pin Name Pin Function 1 COMP The output of the internal transconductance error amplifier. This pin is used for loop compensation. 2 FB The inve rting input of the error amplifier. Tie to an external resistive divider to set the output voltage.

3 SHDN

Shutdown Pin. The accurate 1.1V shutdown threshold and the 4.6uA shutdown pin current hysteresis allow the user to set the undervoltage lockout threshold and hysteresis for the switching regulator. Pulling this pin below 0.1V causes the converter to shut down to low quiescent current. Tie this pin to IN if the UVLO and the shutdown features are not used. This pin should not be left floating. 4 GND Ground. Tie to the ground plane. 5 SW Collector of the in ternal power transistor. Connect to the boost inductor and the rectifying diode. 6 IN Power Supply Pin . Bypassed with capacitors close to the pin. 7 ROSC A resistor from this pin to the ground sets the switching frequency. 8S S Soft-Start Pin. A capacitor from this pin to the ground lengthens the start-up time and reduces start- up current. Exposed Pad The exposed pad must be soldered to the ground plane on the PCB for good thermal conduction. SHDN COMP ROSC REG_GOOD EA FB SS REFERENCE VOLTAGE IN CMP SUPPLY INTERNAL SHUTDOWN THERMAL REG 1.1V 1.242V + 4.6µA ENABLE ENABLE R Q S PWM CLK CLK ISEN ILIM I-LIMIT Σ GND SW R OSCILLATOR SLOPE COMP 1.5µA REG SENSE SIMPLIFIED BLOC DIAGRAM

switch current exceeds the 2.8A current-limit threshold. ILIM therefore provides cycle-by-cycle current limit. amplifier regulates the output voltage. The KB3302 requires a minimum input of 1.4V to operate. pin below 0.1V reduces the total supply current to 10 µA. tied to the FB pin (Figure 4) sets the output voltage. given in the “Typical Characteristics”. 100KHz increase in frequency. Figure 4. The Output Voltage is set with a Resistive Divider

voltage drop across the rectifying diode. to the input. The DC inductor current is the input current. output. The output current is the average diode current. where ILIM is the switch current limit. switching losses are neglected in its derivation. Nevertheless it is a useful first-order approximation. combinations are shown in Table 1. a minimum on time of about 150ns at room temperature. either skip cycles or it will start to jitter. of a Li-ion cell to 5V converter using the KB3302. the minimum duty ratio can be found using (3). Figure 5. Current Waveforms in a Boost Regulator Table 1. Calculated Maximum Output Current [ Equation (4)]

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 APPLICATIONS INFORMATION The absolute maximum operating frequency of the converter is therefore MHz67.1ns150 25.0 ns150 DMIN == . The actual operating frequency needs to be lower to allow for modulating headroom. The power transistor in the KB3302 is turned off every switching period for an interval determined by the discharge time of the oscillator ramp and the propagation delay of the power switch. This minimum off time limits the maximum duty cycle of the regulator at a given switching frequency. A boost converter with high In OUT V V ratio requires long switch on time and high duty cycle. If the required duty cycle is higher than the attainable maximum, then the converter will operate in dropout. (Dropout is a condition in which the regulator cannot attain its set output voltage below current limit.) The minimum off times of closed-loop boost converters set to various output voltages were measured by lowering their input voltages until dropout occurs. It was found that the minimum off time of the KB3302 ranged from 80 to 110ns at room temperature. Beware of dropout when operating at very low input voltages (1.5-2V) and with off times approaching 110ns. Shorten the PCB trace between the power source and the device input pin, as line drop may be a significant percentage of the input voltage. A regulator in dropout may appear as if it is in current limit. The cycle-by-cycle current limit of the KB3302 is duty-cycle and input voltage invariant and is typically 2.8A. If the switch current limit is not at least 2A, then the converter is likely in dropout. The switching frequency should then be lowered to improve controllability. Both the minimum on time and the minimum off time reduce control range of the PWM regulator. Bench measurement showed that reduced modulating range started to be a problem at frequencies over 2MHz. Although the oscillator is capable of running well above 2MHz, controllability limits the maximum operating frequency. Inductor Selection The inductor ripple current ∆I L of a boost converter operating in continuous-conduction mode is fL VVDI CESATIN L −=∆ (5) where f is the switching frequency and L is the inductance. Substituting (3) into (5) and neglecting VCESAT , +−=∆ DOUT ININ L VV V1fL VI (6) In current-mode control, the slope of the modulating (sensed switch current) ramp should be steep enough to lessen jittery tendency but not so steep that large flux swing decreases efficiency. Inductor ripple current ∆I L between 25-40% of the peak inductor current limit is a good compromise. Inductors so chosen are optimized in size and DCR. Setting ∆I +−=⎟⎟ +−∆= 5.0V V1f6.0 V VV V1If VL OUT ININ DOUT IN L IN (7) where L is in µH and f is in MHz. Equation (6) shows that for a given VOUT, ∆IL is the highest when () VVV DOUT IN += . If VIN varies over a wide range, then choose L based on the nominal input voltage. The saturation current of the inductor should be 20-30% higher than the peak current limit (2.8A). Low-cost powder iron cores are not suitable for high-frequency switching power supplies due to their high core losses. Inductors with ferrite cores should be used. Input Capacitor The input current in a boost converter is the inductor current, which is continuous with low RMS current ripples. A 2.2-4.7µF ceramic input capacitor is adequate for most applications. Output Capacitor Both ceramic and low ESR tantalum capacitors can be used as output filtering capacitors. Multi-layer ceramic capacitors, due to their extremely low ESR (<5m Ω), are the best choice. Use ceramic capacitors with stable temperature and voltage characteristics. One may be tempted to use Z5U and Y5V ceramic capacitors for output filtering because of their high capacitance and

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 APPLICATIONS INFORMATION small sizes. However these types of capacitors have high temperature and high voltage coefficients. For example, the capacitance of a Z5U capacitor can drop below 60% of its room temperature value at –25 °C and 90 °C. X5R ceramic capacitors, which have stable temperature and voltage coefficients, are the preferred type. The diode current waveform in Figure 5 is discontinuous with high ripple-content. In a buck converter the inductor ripple current ∆I L determines the output ripple voltage. The output ripple voltage of a boost regulator is however much higher and is determined by the absolute inductor current. Decreasing the inductor ripple current does not appreciably reduce the output ripple voltage. The current flowing in the output filter capacitor is the difference between the diode current and the output current. This capacitor current has a RMS value of: VI IN OUT OUT − (8) If a tantalum capacitor is used, then its ripple current rating in addition to its ESR will need to be considered. When the switch is turned on, the output capacitor supplies the load current I OUT (Figure 5). The output ripple voltage due to charging and discharging of the output capacitor is therefore: OUT OUT OUT C DTIV =∆ (9) For most applications, a 10-22µF ceramic capacitor is sufficient for output filtering. It is worth noting that the output ripple voltage due to discharging of a 10µF ceramic capacitor (9) is higher than that due to its ESR. Rectifying Diode For high efficiency, Schottky barrier diodes should be used as rectifying diodes for the KB3302. These diodes should have a RMS current rating of at least 1A and a reverse blocking voltage of at least a few Volts higher than the output voltage. For switching regulators operating at low duty cycles (i.e. low output voltage to input voltage conversion ratios), it is beneficial to use rectifying diodes with somewhat higher RMS current ratings (thus lower forward voltages). This is because the diode conduction interval is much longer than that of the transistor. Converter efficiency will be improved if the voltage drop across the diode is lower. The rectifying diodes should be placed close to the SW pins of the KB3302 to minimize ringing due to trace inductance. Surface-mount equivalents of 1N5817, 1N5819, MBRM120 (ON Semi) and 10BQ015 (IRF) are all suitable. Soft-Start Soft-start prevents a DC-DC converter from drawing excessive current (equal to the switch current limit) from the power source during start up. If the soft-start time is made sufficiently long, then the output will enter regulation without overshoot. An external capacitor from the SS pin to the ground and an internal 1.5µA charging current source set the soft-start time. The soft-start voltage ramp at the SS pin clamps the error amplifier output. During regulator start-up, COMP voltage follows the SS voltage. The converter starts to switch when its COMP voltage exceeds 0.7V. The peak inductor current is gradually increased until the converter output comes into regulation. If the shutdown pin is forced below 1.1V or if fault is detected, then the soft-start capacitor will be discharged to ground immediately. The SS pin can be left open if soft-start is not required. Shutdown The input voltage and shutdown pin voltage must be greater than 1.4V and 1.1V respectively to enable the KB3302. Forcing the shutdown pin below 1.1V stops switching. Pulling this pin below 0.1V completely shuts off the KB3302. The total V IN current decreases to 10µA at 2V. Figure 6 shows several ways of interfacing the control logic to the shutdown pin. Beware that the shutdown pin is a high impedance pin. It should always be driven from a low- impedance source or tied to a resistive divider. Floating the shutdown pin will result in undefined voltage. In Figure 6(c) the shutdown pin is driven from a logic gate whose V OH is higher than the supply voltage of the KB3302. The diode clamps the maximum shutdown pin voltage to one diode voltage above the input power supply.

Figure 6. Methods of Driving the Shutdown Pin (d) Combining Shutdown with Programmed UVLO (See Section Below).

• Ω−=−=ω C4 and R3 also forms a zero with angular frequency: KHz3.6Krads5.39 pF820K9.30 CR −=−=
• Ω−=−=ω The poles p 1, p2 and the RHP zero z 2 all increase phase shift in the loop response. For stable operation, the overall loop gain should cross 0dB with -20dB/decade slope. Due to the presence of the RHP zero, the 0dB crossover frequency should not be higher than . Placing z1 near p2 nulls its effect and maximizes loop bandwidth. Thus )MAX(OUT 2OUT CVCR ≈ (15) R3 determines the mid-band loop gain of the converter. Increasing R3 increases the mid-band gain and the crossover

Figure 9. Suggested PCB Layout for the KB3302. Notice that there is no via directly under the device. All vias are 12mil in diameter.

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 PACAGE DESCRIPTION - MSOP8 Land Pattern - MSOP-8L-EDP 1.73 2.03.068 .080 F F DETAIL .193 BSC .026 BSC aaa C SEATING ccc C 2X N/2 TIPS INDICATOR PIN 1 bbb C A-B D SEE DETAIL 0.25 A PLANE GAGE .005 N .114 .114 .118 .118 .009 - c (L1) L A 0.13 3.00 3.00

4.90 BSC

0.65 BSC

.122 .122 2.90 2.90 .015 0.22 3.10 3.10 0.38- .010 .004 .016 .003 .024 (.037) .000 .030 0.25 0.10 8° 0° E/2 E A BOTTOM VIEW EXPOSED PAD D bxN DIM ccc e bbb aaa N L D E b c A MILLIMETERS NOM DIMENSIONS INCHES MIN NOM MAX MIN MAX F .076 1.93 - 8° 0.60 (0.95) .032 .009 0.40 0.08 .043 .006 .037 0.75 0.00 0.80 0.23- 0.95 1.10 0.15 3. DIMENSIONS "E1" AND "D" DO NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. -B- CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). DATUMS AND TO BE DETERMINED AT DATUM PLANE NOTES: 2. -A- -H- SIDE VIEW A B C e H e/2 D PLANE REFERENCE JEDEC STD MO-187, VARIATION AA-T.4. THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: MILLIMETERS DIMENSIONS DIM INCHES X Z Y C P G F .081 2.08 (C) F F G Z P X .224 .063 .016 .026 (.161) .098 (4.10) 5.70 1.60 0.40 0.65 2.50

Kingbor Technology Co.,Ltd TEL:(86)0755-26508846 FAX:(86)0755-26509052 PACAGE DESCRIPTION - DFN33 Kingbor Technology TEL:(86)0755-26508846 FAX:(86)0755-26509052 www.kingbor.com MIN aaa bbb b e L N D C E A DIM MILLIMETERS NOM DIMENSIONS MAXNOM INCHES MIN MAX (LASER MARK) INDICATOR PIN 1 N NOTES: CONTROLLING DIMENSIONS ARE IN MILLIMETERS (ANGLES IN DEGREES). COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS TERMINALS.2. .003 .007 .042 .009 .048 .000 .031 (.008) 0.08 0.23 .011 .052 0.18 1.06 .039 .002 0.00 0.80 1.31 0.30 1.21 0.05 1.00 (0.20) .004 0.10 0.50 BSC.020 BSC A aaa C SEATING PLANE A bxN bbb C A B B e C C D LxN E E .087 .055 2.20 1.40 .150 .020 .012 .037 3.80 0.30 0.95 0.50 (.112) .075 1.90 (2.85) K H X THIS LAND PATTERN IS FOR REFERENCE PURPOSES ONLY. CONSULT YOUR MANUFACTURING GROUP TO ENSURE YOUR COMPANY'S MANUFACTURING GUIDELINES ARE MET. NOTES: INCHES DIMENSIONS G K H X Y P Z C DIM MILLIMETERS Y ZG(C) P Land Pattern - DFN33-10