SM6702-27HA

SM6702 series NIPPON PRECISION CIRCUITS INC. PFM Step-up DC/DC Converter OVERVIEW The SM6702 series are step-up DC/DC converter ICs, fabricated using NPC’s Molybdenum-gate CMOS process. They incorporate reference voltage source, error amplifier, oscillator, start-up circuit, PFM (Pulse Frequency Modulation) control circuit into a single chip. The only external components required are a Coil, Diode and output smoothing capacitors to form a step-up DC/DC converter. They employ PFM voltage control circuits to achieve high efficiency, stable constant-voltage output. FEATURES I I I I I I Power dissipation : 24 µW at VIN = 1.5 V, VOUT = 3.0 V, IOUT = 100 µA Start-up input voltage : 0.9 V (max) at RL = 30 kΩ Output voltage : 2.2 V to 3.3 V, available in 0.1 Vstep High efficiency : 85% at VIN = 1.5 V, VOUT = 3.0 V, IOUT = 1 mA Low ripple voltage Package : SOT23-3, SOT89-3 APPLICATIONS I I I I I PDA, Mobile IT equipment Digital Stil Camera Pager Constant-voltage sources for battery-operated equipment Local voltage sources ORDERING INFORMATION D e vice SM6702-33HB SM6702-30HA SM6702-30HB SM6702-27HA SM6702-27HB SM6702-24HA Output voltag e 1 3.3 V 3.0 V 3.0 V 2.7 V 2.7 V 2.4 V P ackag e S O T89-3 S O T23-3 S O T89-3 S O T23-3 S O T89-3 S O T23-3 1 . Stepwise setting with a step of 0.1V in the range of 2.2V to 3.3V is available. NIPPON PRECISION CIRCUITS—1 S M6702 series PINOUT (Top view) SM6702−××HA(SOT23−3) SM6702−××HB(SOT89−3) 3 2 1 2 02 1 2 3 PIN DESCRIPTION Number S M 6 7 0 2 −××H A 1 2 3 S M 6 7 0 2 −××H B 1 3 2 Name VSS LX OUT Ground Switching pin Output (device supply pin) Description PACKAGE DIMENSIONS (Unit : mm) SM6702−××HA(SOT23−3) SM6702−××HB(SOT89−3) 4.5 ± 0.1 1.5 ± 0.1 0.4 ± 0.1 (5 ) 4.0 ± 0.3 0.1 ± 0.05 (8 ) 0.42 ± 0.1 (5 ) 0.37 ± 0.1 2.9 ± 0.2 0 to 15 (0.4) 1.55 ± 0.15 0.2min 1.6 ± 0.2 2.8 ± 0.2 1.1 ± 0.2 0.95 0.95 0.8 ± 0.1 1.1 ± 0.2 0.15 ± 0.1 2.5 ± 0.1 φ1 .0 1.5 1.5 (8 ) 0.4 ± 0.1 0.2 M 0.05 ± 0.05 0.42 ± 0.1 0.47 ± 0.1 NIPPON PRECISION CIRCUITS—2 S M6702 series BLOCK DIAGRAM OUT LX PFM OSC VREF START−UP VSS NIPPON PRECISION CIRCUITS—3 S M6702 series SPECIFICATIONS Absolute Maximum Ratings Ta = 25 °C P arameter L X impressed voltage OUT impressed voltage LX output current Pow er dissipation Operating temperature Storage temperature Symbol V LX VOUT IL X PD T o pr T s tg S M 6 7 0 2 −××H A S M 6 7 0 2 −××H B Condition Rating 5 4 2 00 150 mW 500 − 2 0 to 70 − 4 0 to 125 °C °C Unit V V mA Electrical Characteristics L = 330 µH, C = 22 µF, Ta = 25 °C, VSS = 0 V Rating P arameter S tart-up voltage Holding voltage Current consumption Output voltage Symbol V st V h old IS S VOUT IL X IL X L fO S C Duty V IN R L = 30 kΩ R L = 3 kΩ V I N = 1 .5 V, R L = 3 0 k Ω V I N = 1 .5 V, R L = 3 k Ω V O U T = V t arget − 0 .1, V L X = 0 .4 V V O U T = V L X = 3 .5 V V O U T = V t arget − 0 .1 V O U T = V t arget − 0 .1 2.2 ≤ V t arget ≤ 2 .7 2.8 ≤ V t arget ≤ 3 .3 Condition min – – – V t arget × 0 .975 60 80 – 80 65 – typ – – 8 V t arget – – – 100 75 – max 0.9 0.7 16 V t arget × 1 .025 – mA – 1 120 85 V t arget + 0 .2 µA kHz % V V V µA V Unit LX output current LX leakage current M a x i m um oscillator frequency Switch ON duty cycle Input voltage range V t arget : S etting output voltage NIPPON PRECISION CIRCUITS—4 S M6702 series FUNCTIONAL DESCRIPTION Step-up Principle The SM6702 series use a transistor to switch the input supply in a non-isolated chopper switching regulator configuration. The figure below shows the basic step-up switching regulator circuit. If the transistor is ON for an interval tON and then instantly turned OFF, the energy stored in the coil L during the interval tON generates a voltage VL across the coil. This voltage is superimposed on the input voltage such that the peak voltage reaches VIN + VL which forces the diode D to conduct and release the stored energy into the output. During normal operation, the above switching occurs repeatedly at a frequency controlled by an oscillator (which can change depending on the input and output load conditions), generating a square wave output which is then smoothed by the output capacitor C. Thus the output voltage (VOUT > VIN) has been stepped up. L VIN D VOUT Tr C GND PFM Control In SM6702 series, the LX transistor ON interval is fixed, and the OFF interval varies in response to the input voltage and load changes. Thus the resulting switching cycle frequency varies, called pulse frequency modulation. NIPPON PRECISION CIRCUITS—5 S M6702 series BASIC CIRCUIT VIN L D OUT C + LX VSS OUT C oil (L) : 330 µH Diode (D) : MA721 (Matsushita Schottky diode) Capacitor (C L ) : 2 2 µF tantalum TYPICAL APPLICATION CIRCUIT L D 3V System Voltage + LX C2 VSS OUT + 1.5V C1 C3 Coil (L) : 330 µH Schottky Diode (D) Capacitor (C1) : 22 µF tantalum Capacitor (C2) : 0.22 µF ceramic Capacitor (C3) : 22 µF tantalum NIPPON PRECISION CIRCUITS—6 S M6702 series BASIC CHARACTERISTICS Output voltage vs. Output current L=330µH, C=22µF SM6702-30HA (Vout : 3.0V) 3.5 3 3.5 L=470µH, C=22µF Vin=1.5V Vin=0.9V Vin=1.2V Vin=1.5V 3 Output Voltage Vout[V] Output Voltage Vout[V] 2.5 2 1.5 1 0.5 0 0 Vin=0.9V Vin=1.2V 2.5 2 1.5 1 0.5 5 10 15 20 25 Output Current Iout[mA] 30 0 0 5 10 15 20 25 Output Current Iout[mA] 30 Efficiency vs. Output current 100 95 90 85 L=330µH, C=22µF 100 95 90 L=470µH, C=22µF Efficiency [%] 80 75 70 Efficiency [%] 85 80 75 70 65 Vin=1.2V 60 55 50 Vin=1.5V Vin=0.9V Vin=0.9V Vin=1.5V Vin=1.2V 65 60 55 50 0 5 10 15 20 25 Output Current Iout[mA] 30 0 5 10 15 20 25 30 Output Current Iout[mA] Ripple voltage vs. Output current L=330µH, C=22µF 200 175 Ripple Voltage Vr[mVpp] 150 125 100 75 50 25 Vin=0.9V 0 0 10 20 30 40 50 60 Output Current Iout[mA] Vin=1.5V Vin=1.2V NIPPON PRECISION CIRCUITS—7 S M6702 series Output voltage vs. Temperature Vin=1.5V, L=330µH, RL=3kΩ Maximum oscillator frequency vs. Temperature 200 Maximum Oscillator Frequency fosc[kHz] 175 150 125 100 75 50 25 0 Vout=2.9V 3.2 Output Voltage Vout[V] 3.1 3.0 2.9 2.8 -40 -20 0 20 40 Temperature [°C] 60 80 -40 -20 0 20 40 Temperature [°C] 60 80 Start-up voltage vs. Temperature 1.0 L=330µH, RL=30kΩ Hold-on voltage vs. Temperature 1.0 L=330µH, RL=3kΩ 0.8 Hold-on Voltage Vhold[V] -40 -20 0 20 40 Temperature [°C] 60 80 Start-up Voltage Vst[V] 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 0.0 -40 -20 0 20 40 Temperature [°C] 60 80 Current consumption vs. Temperature 10 Vin=1.5V, L=330µH, RL=30kΩ Oscillator duty cycle vs. Temperature 90 85 Vout=2.9V Current Consumption Iss[µA] 8 Oscillator Duty Cycle [%] 80 75 70 65 60 55 0 -40 -20 0 20 40 Temperature [°C] 60 80 50 -40 -20 0 20 40 Temperature [°C] 60 80 6 4 2 NIPPON PRECISION CIRCUITS—8 S M6702 series LX switching current vs. Temperature 200 175 LX Switching Current ILX[mA] 150 125 100 75 50 25 0 -40 -20 0 20 40 Temperature [°C] 60 80 Vout=2.9V LX leakage current vs. Temperature 100 Vin=Vout=3.5V LX Leakage Current ILXL[nA] 10 1 0.1 -40 -20 0 20 40 Temperature [°C] 60 80 NIPPON PRECISION CIRCUITS—9 S M6702 series NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without further testing or modification. The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter, including compliance with expor t controls on the distribution or dissemination of the products. Customers shall not expor t, directly or indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies. NIPPON PRECISION CIRCUITS INC. 4-3, Fukuzumi 2-chome Koto-ku, Tokyo 135-8430, Japan Telephone: +81-3-3642-6661 Facsimile: +81-3-3642-6698 http://www.npc.co.jp/ Email: sales @ npc.co.jp NC9721CE 2000.10 NIPPON PRECISION CIRCUITS INC. NIPPON PRECISION CIRCUITS—10