SS6620COTR

SS6620 SSC | Alldatasheet

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www.SiliconStandard.com 1 of 12 SS6620/21/2 High Efficiency Synchronous Step-Up DC/DC Converter n FEATURES l High efficiency of 93 % (VIN=2.4V, VOUT=3.3V, IOUT=200mA). l Quiescent supply current of 20µA. l Power-saving shutdown mode (0.1µA typical). l Internal synchronous rectifier (no external diode ) l Selectable current limit for reduced ripple (SS6622). l Low noise, anti-ringing feature (SS6622) l On-chip low-battery detector. l Low-battery hysteresis n APPLICATIONS l Palmtop & notebook computers. l PDAs l Wireless phones l Pocket organizers. l Cameras. l 1 to 2-cell hand-held devices n DESCRIPTION The SS6620/21/22 are high-efficiency step- up DC/DC converters, with start-up vol tage as low as 0.8V and operating with an i nput voltage down to 0.7V. Co nsuming only 20 µA of quie s- cent current, these devices offer a built -in syn- chronous rectifier that r educes size and cost by eliminating the need for an exte rnal Schottky diode, improving overall efficiency by minimi z- ing losses. The switching frequency depends on the load and the input voltage and can range up to 500KHz. The peak current of the internal switch is fixed at 0.8A (SS6620), at 0.45A (SS6621), or is selectable (SS6622) for design flex ibility. Ri pple does not exceed the product of the switch current limit and the filter capacitor equivalent -series-resistance (ESR) . The SS6622 also features a circuit that eliminates noise caused by inductor ringing. n TYPICAL APPLICATION CIRCUIT Output 3.3V, or Adj. (1.8V to 4.0V) up to 300mA Low-Battery Detect Out FB GND ON OFF Low-Battery Detect In 0.1µF VIN 22µH 220µF 100µF SS6620 SS6621 SS6622 OUT REF LBO SHDN LX LBI LBO FB Rev.2.01 6/06/2003

www.SiliconStandard.com 2 of 12 SS6620/21/2 n ORDERING INFORMATION SS6620CX XX SS6621CX XX SS6622CX XX PIN CONFIGURATION (MSOP8) TOP VIEW SS6622 FB LBI LBO CLSEL REF OUT LX GND BATT SHDN 5 6 (MSOP10) TOP VIEW GND OUT LBI LBO REF LX SHDN FB SS6620 SS6621 Example: SS6620COTR à In MSO P8 Package in Tap e & Reel PACKING TYPE TR: TAPE & REEL PACKAGING TYPE O: MSOP8 (for SS6620/1) O: MSOP10 (for SS6622) n ABSOLUTE MAXIMUM RATINGS Supply Voltage (OUT to GND) 8.0V Switch Voltage (LX to GND) VOUT+ 0.3V Battery Voltage (Batt to GND) 6.0V , LBO to GND 6.0V LBI, REF, FB, CLSEL to GND VOUT+0.3V Switch Current (LX) -1.5A to +1.5A Output Current (OUT) -1.5A to +1.5A Operating Temperature Range -40°C ~ +85°C Storage Temperature Range -65°C ~150°C n TEST CIRCUIT Refer to Typical Application Circuit. SHDN Rev.2.01 6/06/2003

www.SiliconStandard.com 3 of 12 SS6620/21/2 n ELECTRICAL CHARACTERISTICS (VBATT=2.0V, VOUT=3.3V (FB=VOUT), RL=µ, TA=25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS MIN. TYP. MAX. UNIT Minimum Input Voltage 0.7 V Operating Voltage 1.1 4.0 V Start-Up Voltage RL=3KΩ (Note1) 0.8 1.1 V Start-Up Voltage Tempco -2 mV/°C Output Voltage Range 1.8 4.0 Output Voltage FB = VOUT 3.17 3.3 3.43 V SS6620 SS6622 (CLSEL=OUT) 300 400 Steady State Output Current (Note 2) FB=OUT (VOUT =3.3V) SS6621 SS6622 (CLSEL=GND) 150 220 mA Reference Voltage IREF= 0 1.199 1.23 1.261 V Reference Voltage Tempco 0.024 mV/°C Reference Load Regulation IREF = 0 to 100 µA 10 30 mV Reference Line Regulation VOUT = 1.8V to 4V 5 10 mV/V FB , LBI Input Threshold 1.199 1.23 1.261 V Internal Switch On-Resistance ILX = 100mA 0.3 Ω SS6620,SS6622(CLSEL = OUT) 0.6 0.8 1.0 LX Switch Current Limit SS6621,SS6622(CLSEL = GND) 0.3 0.45 0.6 A LX Leakage Current VLX=0V, 4V; VOUT=4V 0.05 1 µA Operating Current into OUT (Note 3) VFB = 1.4V , VOUT = 3.3V 20 35 µA Shutdown Current into OUT SHDN = GND 0.1 1 µA VOUT= 3.3V ,ILOAD = 200mA 90 Efficiency VOUT = 2V ,ILOAD = 1mA 85 LX Switch On-Time VFB =1V , VOUT = 3.3V 2 4 7 µs LX Switch Off-Time VFB =1V , VOUT = 3.3V 0.6 0.9 1.3 µs FB Input Current VFB = 1.4V 0.03 50 nA Rev.2.01 6/06/2003

www.SiliconStandard.com 4 of 12 SS6620/21/2 n ELECTRICAL CHARACTERISTICS (Continued) PARAMETER TEST CONDITIONS MIN. TYP. MAX. UNIT LBI Input Current VLBI = 1.4V 1 50 nA CLSEL Input Current SS6622 , CLSEL = OUT 1.4 3 µA SHDN Input Current VSHDN = 0 or VOUT 0.07 50 nA LBO Low Output Voltage VLBI = 0, ISINK = 1mA 0.2 0.4 µA LBO Off Leakage Current VLBO = 5.5V, VLBI = 5.5V 0.07 1 LBI Hystereisis 50 mV Damping Switch Resistance SS6622, VBATT = 2V 50 100 Ω 0.2VOUT SHDN Input Voltage 0.8VOUT V 0.2VOUT CLSEL Input Voltage 0.8VOUT V Note 1: Start-up voltage operation is guaranteed without the addition of an external Schottky diode between the in- put and output. Note 2: Steady-state output current indicates that the device maintains output voltage regulation under load. Note 3: Device is bootstrapped (power to the IC comes from OUT). This correlates directly with the actual battery supply. n TYPICAL PERFORMANCE CHARACTERISTICS 0.01 0.1 1 10 100 1000 100 Fig. 1 VOUT=3.3V CLSEL=OUT (0.8A) VIN=2.4V VIN=1.2V Efficiency (%) Loading (mA) 100 120 140 160 I_limit=0.45A , VOUT=3.3V Input Battery Current (µA) Input battery voltage (V) Fig. 2 No-Load Battery Current vs. Input Battery Voltage I_limit=0.8A , VOUT=3.3V Rev.2.01 6/06/2003

www.SiliconStandard.com 5 of 12 SS6620/21/2 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) 0.01 0.1 1 10 100 1000 Fig. 3 VOUT=3.3V CLSEL=GND (0.45A) Efficiency (%) Loading (mA) 100 VIN=2.4V VIN=1.2V 0.01 0.1 1 10 1000.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 Fig. 4 Start-up Voltage vs. Load Current Without Diode With Diode Start-up Voltage (V) Load Current (mA) -0.08 -0.06 -0.04 -0.02 0.00 0.02 0.04 0.06 0.08 0.10 Fig. 5 Shutdown Current vs. VOUT Shutdown Current (µA) VOUT (V) 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 Fig. 6 Shutdown Threshold vs. Output Voltage Shutdown Threshold (V) Output Voltage (V) 100 200 300 400 500 600 700 800 Fig. 7 Maximum Output Current vs. Input Voltage CLSEL=OUT CLSEL=GND Maximum Output Current (mA) Input Voltage (V) VOUT=3.3V Fig. 8 Heavy Load Waveform LX pin waveform VOUT AC Couple Inductor Current VIN=2.4V VOUT=3.3V Rev.2.01 6/06/2003

www.SiliconStandard.com 6 of 12 SS6620/21/2 n TYPICAL PERFORMANCE CHARACTERISTICS (Continued) Fig. 9 Without Damping Ringing Function Fig. 10 With Damping Ringing Function Δ IOUT=200mA VOUT AC Couple Fig. 11 Load Transient Response VIN=2.4V VOUT=3.3V Rev.2.01 6/06/2003

www.SiliconStandard.com 7 of 12 SS6620/21/2 n BLOCK DIAGRAM OUT VIN CLSEL SHDN LBO LBI REF FB Mirror Q R S F/F Minimum Off-Time One Shot Ref erence Voltage GND LX BATT L 200ΩQ3 Q1 Damping Switch Maximum On-Time OUT One Shot 220µF 100µF 47µF 0.1µF 0.1µF n PIN DESCRIPTIONS SS6620/ SS6621 PIN 1: FB- Connect to OUT for +3.3V output. Use a resistor network to set the ou t- put voltage from +1.8V to +4.0V. PIN 2: LBI- Low-battery comparator input. Inter- nally set to trip at +1.23V. PIN 3: LBO- Open-drain low battery comparator output. Output is low when VLBI is <1.23V. LBO is high impedance du r- ing shutdown. PIN 4: REF- 1.23V reference voltage. Bypass with a 0.1µF capacitor. PIN 5: SHDN- Shutdown input. High=operating, low=shutdown. PIN 6: GND- Ground PIN 7: LX- N-channel and P-channel power MOSFET drain. PIN 8: OUT- Power output. OUT provides boo t- strap power to the IC. Rev.2.01 6/06/2003

www.SiliconStandard.com 8 of 12 SS6620/21/2 SS6622 PIN 1: FB- Connect to OUT for +3.3V output. Use a resistor network to set the ou t- put voltage from +1.8V to +4.0V. PIN 2: LBI- Low-Battery comparator input. Inter- nally set to trip at +1.23V. PIN 3: LBO- Open-drain low battery comparator output. Output is low when VLBI is <1.23V. LBO is high impedance du r- ing shutdown. PIN 4: CLSEL- Current-limit selects input. CLSEL= OUT sets the current limit to 0.8A. CLSEL=GND sets the current limit to 0.45A. PIN 5: REF- 1.23V reference voltage. Bypass with a 0.1µF capacitor. PIN 6: SHDN- Shutdown input. High=operating, low=shutdown. PIN 7: BATT- Battery input and damping switch connection. If damping switch is unused, leave BATT unco nnected. PIN 8: GND- Ground. PIN 9: LX- N-channel and P-channel power MOSFET drain. PIN 10: OUT- Power output. OUT provides boot- strap power to the IC. n APPLICATION INFORMATION Overview The SS6620/21/22 series are high efficiency, step-up DC/ DC converters, designed to fe ature a built-in synchronous rectifier, which reduces size and cost by eliminating the need for an external Schottky diode. The start-up voltage is as low as 0.8V and they can operate with an input voltage down to 0.7V. Qu i- escent supply cu rrent is only 20µA. In addition, the SS6622 feature a circuit that eliminates inductor- ringing to reduce noise. The internal P-MOSFET on- resistance is typ ically 0.3 Ω to improve overall eff i- ciency by minimizing AC loss es. The current limit of the SS6620 and SS6621 is 0.8A and 0.45A respectively. The SS6622 offers a selectable current- limit (0.45A or 0.8A). The lower current limit allows the use of a physically smaller inductor in space- sensitive applications. PFM Control Scheme The key feature of the SS6620 series is a unique minimum-off-time, current -limited, pulse -frequency- modulation (PFM) control scheme (see BLOCK DIAGRAM) with ultra-low quiescent cu rrent. A co n- stant-peak-current limit in the switching allows the in- ductor current to vary between this peak limit and some lesser value. The peak current of the internal N- MOSFET power switch can be fixed at 0.8A, 0.45A or is selectable. T he ripple vol tage does not exceed the product of the peak current limit and the filter c apaci- tor equivalent -series-resistance ( ESR). The switch frequency depends on the loading condition and input voltage, and can range up to 500KHz. The switching frequency is governed by a pair of one -shots that set a minimum off -time (1µs) and a max imum on -time (4µs). Rev.2.01 6/06/2003

www.SiliconStandard.com 9 of 12 SS6620/21/2 Synchronous Rectification Using the internal synchronous rectifier eliminates the need for an external Schottky diode. Therefore, the cost and board space is reduced. During the cycle of off-time, the P-MOSFET tu rns on and shunts the N- MOSFET. Due to the low turn-on resistance of the MOSFET, the synchronous rectifier si gnificantly im- proves eff iciency without the addition of an external component. Thus, the conversion efficiency can be as high as 93%. Reference Voltage The reference voltage (REF) is nominally 1.2 3V for excellent T.C. performance. In addition, the REF pin can source up to 100µA to an external circuit with good load regulation (<10mV). A bypass capacitor of 0.1µF is required for proper operation and good pe r- formance. Shutdown The whole circuit is shutdown when SHDNV is low. During shutdown mode, current can flow from the ba t- tery to the output through the body diode of the P- MOSFET. VOUT falls to approximately (Vin - 0.6V) and LX remains high impedance. The capacitance and load at OUT determine the rate at which V OUT decays. Shutdown can be pulled as high as 6V, regardless of the voltage at OUT. Current Limit Select Pin The SS6622 series allows a selectable inductor current limit of either 0. 45A or 0.8A. This allows flex i- bility in designing for higher current or smaller appl i- cations. CLSEL draws 1.4µA when connected to OUT. BATT/Damping Switch The SS6622 is designed with an internal damping switch (Fig. 15) to reduce ringing at LX. The damping switch supplies a path to quickly dissipate the e nergy stored in the inductor and reduces the ringing at LX. Damping LX ri nging does not reduce V OUT ripple, but does reduce EMI. A value of R1=200Ω works well for most application while reducing efficiency by only 1%. Larger R1 value s provide less damping, but less im- pact on efficiency. In principle, lower value s of R1 are needed to fully da mp LX when the VOUT /V IN ratio is high. Selecting the Output Voltage VOUT can be simply set to 3.3V by connecting the FB pin to OUT due to the internal resistor divider (Fig. 16). In order to adjust the output voltage, a resistor divider is connected to V OUT, FB, GND (Fig. 17). Use the following equation to calculate: R5=R6 [(VOUT / VREF )-1] where VREF =1.23V and VOUT may range from 1.8V to 4V. Low-Battery Detection The SS6620 series contain an on-chip comparator with 50mV internal hysteresis (REF, REF +50mV) for low battery detection. If the voltage at LBI falls b elow the internal reference voltage , LBO (an open -drain output) sinks current to GND. Rev.2.01 6/06/2003

plications that can tolerate higher output ripple. Figure 12. Top layer Figure 13. Bottom layer Figure 14. Placement

www.SiliconStandard.com 11 of 12 SS6620/21/2 n APPLICATION EXAMPLES DAMPING SWITCH VIN VOUT SS6622 OUT BATT LX GND 200Ω 22µH VOUT VIN (SS6622) R2 100K Ω SS6620 SS6621 SS6622 C1 L 22µH 100µF 220µF 0.1µF 0.1µF R1 200 Ω ohm LOW BATTERY OUTPUT CLSEL (SS6622) LX OUT FB GND REF LBI BATT LBO SHDN Fig. 17 An Adjustable Output Application Circuit VOUT VIN 100KΩ 200Ω 22µH 100µF 220µF 0.1µF 0.1µF LOW BATTERY OUTPUT C1 L (SS6622) SS6622 SS6621 SS6620 R6 R5 R4 SHDN CLSEL (SS6622) LX FB LBO GND REF LBI BATT OUT Rev.2.01 6/06/2003

Information furnished by Silicon Standard Corporation is believed to be accurate and reliable. However, Silicon Standard Corporation makes no guarantee or warranty, express or implied, as to the reliability, accuracy, timeliness or completeness of such information and assumes no responsibility for its use, or for infr ingement of any patent or other intellectual property rights of third parties that may result from its use. Silicon Standard reserves the right to make changes as it deems necessary to any products described herein for any reason, including without limitation enhancement in reliability, functionality or design. No license is granted, whether expressly or by implication, in relation to the use of any products described herein or to the use of any information provided herein, under any patent or other intellectual property rights of Silicon Standard Corporation or any third parties. www.SiliconStandard.com 12 of 12 SS6620/21/2 n PHYSICAL DIMENSION l 8 LEAD MSOP (unit: mm) SYMBOL MIN MAX A1 -- 0.20 A2 0.76 0.97 b 0.28 0.38 C 0.13 0.23 D 2.90 3.10 E 4.80 5.00 E1 2.90 3.10 e 0.65 L 0.40 0.66 D E e b C L l 10 LEAD MSOP (unit: mm) SYMBOL MIN MAX A1 -- 0.20 A2 0.76 0.97 b 0.15 0.30 C 0.13 0.23 D 2.90 3.10 E 4.80 5.00 E1 2.90 3.10 e 0.50 L 0.40 0.66 D E e b C L Rev.2.01 6/06/2003