19-0202; Rev 2: 11/96 MA AALIV 5V/12V/15V or Adjustable, High-Efficiency, Low /1Q, Step-Up DC-DC Controllers General Description The MAX770-MAX773 step-up switching controllers pro- vide 90% efficiency over a 10mA to 1A load. A unique currentlimited pulse-frequency-medulation (PFM) control scheme gives these devices the benefits of pulse-width-modulation (PWM) converters (high efficiency at heavy loads), while using less than 110yA of supply current (vs. 2mA to 10mA for PWM converters). These ICs use tiny external components. Their high switching frequencies (up to 300kHz) allow surface- mount magnetics of 5mm height and 9mm diameter. The MAX? 70/MAX771/MAX772 accept input voltages from 2V to 16.5. Output voltages are preset at 5V, (MAX770), 12V (MAX771), and 15V (MAX772); they can also be adjusted using two resistors. The MAX773 accepts inputs from 3V to 16.5V. For a wider input range, it features an internal shunt regulator that allows unlimited higher input voltages. The MAX773s out put can be set to 5V, 12V, or 15V, or it can be adjusted with two resistors. The MAX770-MAX773 drive external N-channel MOSFET switches, allowing them to power loads up to 15W. If less power is required, use the MAX756/MAX75/7 or MAX761/MAX762 step-up switching regulators with on- Features 90% Efficiency for 10mA to 1A Load Currents Up to 15W Output Power 110HA Max Supply Current 5A Max Shutdown Current 2V to 16.5V Input Range (MAX770/MAX771/MAX772) Internal Shunt Regulator for High Input Voltages (MAX773) + Preset or Adjustable Output Voltages MAX770: 5V or Adjustable MAX771: 12V or Adjustable MAX?772: 15V or Adjustable MAX773: 5V, 12V, 15V, or Adjustable Current-Limited PFM Control Scheme 300kHz Switching Frequency + Ordering Information board MOSFETs. Applications Palmtops/Handy-Terminals High-Efficiency DC-DC Converters Battery-Powered Applications Positive LCD-Bias Generators Portable Communicators Flash Memory Programmers Typical Operating Circuit PART TEMP. RANGE PIN-PACKAGE MAX770CPA 0 to +70%C Plastic DIP MAX770CSA 0T to +70 830 MAX770C/D 0 to +70%S Dice* MAX770EPA -40% to +85C 8 Plastic DIP MAX770E8A -40 to +85C &8sO MAX770MJA -55C to +125C 8 GERDIP** INPUT 2V TO VOUT = MAXLAN MAX777 ET cs ON/OFF 4 SHDN FEF Vt FB AGND GND OUTPUT 12 HHA Ordering Information continued at end of daia sheet. *Contact faciory for dice specifications. Contact factory for availability and processing to MIL-STD-883B. Pin Configurations TOP VIEW . er Li MAXIM el cs vey Mac [zl aw MAX771 rs Ls] Mao 6 | AGND SHDN [4] [5] PEF DIP/SO Pin Configurations continued at end of daia sheet. MAXIMA Maxim Iniegrated Producis 1 For free samples & the latest literature: hitp:/www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468. EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers ABSOLUTE MAXIMUM RATINGS Supply Voltages 14-Pin Plastic DIP V+ to GND. cece ce cneeceeceeeeeeeeeneenae -0.3 to 17V (derate 10.00mMW/G above +70C) oe 800mWw V+ to SGND.... ve -0.3V to 7V 14-Pin SO (derate 8.338mMW/G above +70C) 0. 667mW SGND oo. eeceeeeeceeeeeeeeneeseteeneeeerens -0.3V to (V+ + 0.3V) 14-Pin CERDIP (derate 9.09mW/C above +70%)......727mW EXT, GS, REF, LBO, LBI, SHDN, FB............. -0.3V to (V+ + 0.3V) Operating Temperature Ranges EXTH, EXTL oo... eee ce ccccecceeceeeeeeteeeeeeeeaes ..-0.3V to (V+ + O.3V) MAX7 7 Ceci cece ceceeeeesceeteteenteceeenes 06 to +70 V5, VA12, VAS ccccccccccececsecserscstsesernsceesvsesevtseseeesnarees -0.3V to 17V MAX77_E 40C to +85C GND to AGND oo... eee ce cee e cece teteeteteereenieees 0.1V to -0.1V MAX?T7 Md oo. cee eeeeeeeeteceeeeeeeereeneeee -55 CT to +125 [SGD ..eececeec cece cecee cee cceeeseeeeeececeeceeeeaeeseesereeneesneeeteneeeeeitee 50mA Junction Temperatures Continuous Power Dissipation (TA = +70) MAX77 GE ccc cccccessecccescsseeeseneeaseeseneseeeaeenes +150 8-Pin Plastic DIP (derate 9.09mW/S above +70%)}....727mW MAX? 7 Md one. cc cece cece cence eeeeeee sees seceeeaeeeeeeesneneenaees 4175 8-Pin SO (derate 5.88mMW/G above +70)... 471mWw Storage Temperature Range........0...c eee -65C to +160C 8-Pin GERDIP (derate 8.0OmW/C above +70)........640mW Lead Temperature (soldering, 108eC}....0..000.0 ee +300C Stresses beyond those listed under Absolute Maximum Aatings may cause permanent damage to the device. These are siress ratings only, and functional operation of the device af these or any other condilions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V+ = 5V, ILoaD = OmA, Ta = TMIN to TMAX, Unless otherwise noted. Typical values are at Ta = +25C.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX | UNITS MAX770-772 (internal feedback resistors) 2.0 16.5 MAX?770-772GC/E (external resistors) 3.0 16.5 Input Voltage Range MAX770-772MJA {external resistors) 3.1 16.5 Vv MAX773G/E 3.0 16.5 MAX773MJD 3.1 16.5 Minimum Start-Up Voltage MAX770/MAX771/MAX772 1.8 2.0 Vv Supply Current V+ = 16.5V, SHDN = OV (normal operation) 85 110 HA V+ = 10.0V, SHDN = 1.6V (shutdown) 2 5 Standby Current HA V+ = 16.5V, SHDN > 1.6V (shutdown) 4 V+ = 2.0 to 5.0V, over full load range 4.80 5.0 5.20 Quiput Voltage (Note 1) V+ = 2.0V to 12.0V, over full load range 11.52 12.0 12.48 Vv V+ = 2.0V to 15.0V, over full load range 14.40 15.0 15.60 Output Voltage Line Regulation Figure 2a, V+ = 2.7V to 4.5V, 5 mViV (Note 2} lLoaD = 700mA, VouT = 5V Cutput Voltage Load Regulation Figure 2a, V+ = 3V, lloap = 30mA to 1A, 20 mViA (Note 2} Vout = 5V Maximum Switch On-Time ton(max) 12 16 20 ps Minimum Switch Off-Time torr(min) 1.8 2.3 2.8 ps Efficiency V+ = 4V, lLloap = 500mA, Vout = 5V a7 % MAX77_C 1.4700 1.5 1.5300 Reference Voltage VREF IREF = OWA MAX77_E 1.4625 15 1.5375 V MAX77_M 1.4550 1.5 1.5450 MAXLAN5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers ELECTRICAL CHARACTERISTICS (continued) (V+ = 5V, ILoap = OmA, Ta = TIN to Tmax, Unless otherwise noted. Typical values are at Ta = +25C.) PARAMETERS SYMBOL CONDITIONS MIN TYP MAX UNITS REF Load Regulation OwA <IREFS 100nA MAIZSIE + mV MAX77_M 4 15 REF Line Regulation 3V < V+ < 16.5V 40 100 piv MAX77_C 1.4700 1.50 1.5300 FB Trip-Point Voltage VFB MAX77_E 1.4625 1.50 1.5375 Vv MAX77_M 1.4550 1.50 1.5450 MAX77_C +20 FB Input Current IFB MAX77_E +40 nA MAX77_M +60 SHDN Input High Voltage VIH V+ = 2.0V to 16.5V 1.6 Vv SHDN Input Low Voltage Vib MAX77_G/E, V+ = 2.0V to 16.5V 0.4 Vv MAX77_M, V+ = 2.0V to 16.5V 0.2 SHDN Input Current V+ = 16.5V, SHDN = OV or V+ +1 pA LBI Input Current MAX773, V+ = 16.5V, LBI = 1.5V +20 nA LBI Hysteresis MAX773 20 mV LBI Delay 5mV overdrive 2.5 us MAX?7_G 1.4700 1.50 1.5300 LBI Threshold Voltage MAX773, LBI falling MAX77_E 1.4625 1.50 1.5375 V MAX77_M 1.4550 1.50 1.5450 LBO Leakage Current MAX773, V+ = 16.5V, VLBo = 16.5V 0.01 1.00 LA LBO Output Voltage Low VoL MAX?73, V+ = 5V, LBO sinking 1mA 0.1 0.4 Vv Current-Limit Trip Level Ves V+ = 5Vto 16.5V 170 200 230 mV CS Input Current 0.01 +1 HA EXT Rise Time V+ = 5V, 1nF from EXT to ground (Note 3) 55 ns EXT Fall Time V+ = 5V, 1nF from EXT to ground (Note 3) 55 ns pen et vue | MANS Jovan maaan 58 sa |v Note 1: Output voltage guaranteed using preset voltages. See Figures 7a/d for output current capability versus input voltage. Note 2: Output voltage line and load regulation depend on external circuit components. Note 3: For the MAX773, EXT is EXTH and EXTL shorted together. MA AXIAA EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Typical Operating Characteristics (TA = +25, unless otherwise noted.) MAX?770 MAX?771 MAX772 EFFICIENCY vs. OUTPUT CURRENT EFFICIENCY vs. QUTPUT CURRENT EFFICIENCY vs. OUTPUT CURRENT (BCOTSTRAPPED) (BCOTSTRAPPED) (BOOTSTRAPPED) 5 100 g 100 8 2 Vout = 18V, GIRGUIT OF FIGURE 2b 3 5 Vin = 8 |||] Vin = 6 g MAX772 SUBSTITUTED FOR MAX?771 5 = 50 = 90 = Q = 80 > 80 fa a fa Qo 5 So i f 70 t 70 Vin=1 Wo Wu N= 9V VouT= 5 60 Vout= 12 60 w= BY CIRCUIT OF CIRCUIT OF IN=5 FIGURE 2a FIGURE 2b Vin=3 0 50 9.001 0.01 0.1 1 0.001 0.01 0.1 1 0.004 oot 0.1 1 QUTPUT CURRENT (A) OUTPUT CURRENT (Aj QUTPUT GURRENT {A} MAX771 MAX770 MAX771 EFFICIENCY vs. QUTPUT CURRENT LOAD CURRENT vs. LOAD CURRENT vs. (NON-BOOTSTRAPPED} MINIMUM START-UP INPUT VOLTAGE MINIMUM START-UP INPUT VOLTAGE 400 TTT 3 700 T / 8 500 T 8 Vout =12V _5 45 gE VouT=5 g Vout = 12 g CIRCUIT OF 3 600 | oieurtor V g CIRCUITOF 5 FIGURE 2c FIGURE 2a / 400 [ FIGURE 2b Ll z 500 z = 90 ra E = R ra NA = / = = LA Z 400 Z 300 Qo Jaa io ) 4 Lat" ~~ Ee / fe oO LA g 300 2 i er a apove 34Y, Q 200 ABOVE 3.5V 80 S apo THEGIRCUIT 3 THESIACUIT 4 STARTS UP 7] = STARTS UP V4 UNDER 400 UNDER 00 LY MAXIMUM _| 7 MAXIMUM LOAD 40 9 CONDITIONS 9 _ CONDITICNS 0.001 0.04 0. 1.0 is 2.0 25 3.0 35 2.0 25 3.0 35 4.0 OUTPUT CURRENT (A) MINIMUM START-UP INPUT VOLTAGE () MINIMUM START-UP INPUT VOLTAGE () SUPPLY CURRENT vs. TEMPERATURE SUPPLY CURRENT vs. SUPPLY VOLTAGE EXT RISE/FALL TIME vs. SUPPLY VOLTAGE 4 $$ 5 08 | 8 250 g Vout =12V, Vin =5 e 5 3 3% CIRCUIT OF FIGURE 2b g Vour=12V 0G E BOOTSTRAPPED MODE 5 _ ie = 200 = =z 3 Z08 | __ BOOTSTRAPPED 2 Cent = 2200F < = _ ENTIRE S RGURESL = Cext = 1000pF G = 18 i GIR AL fe \ 4 A 0 Cext = 446pF ce a 5B o4 X\ = Ceyt = 100pF o o in 2 > @ 100 & & a EAKAGE EXCL DED Boz} \ ai / AL Pee, 50 Ph NON-BOOTSTRAPPED CIRCUIT OF FIGURE 26 Q Q 0 75 -50 -25 0 #5 50 75 100 125 2 4 5 8 10 te TEM PERATURE (C) SUPPLY VOLTAGE (}5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Typical Operating Characteristics (continued) (TA = +25, unless otherwise noted.) REFERENCE QUTPLT RESISTANCE vs. TEM PERATURE REFERENCE vs. TEMPERATURE 250 e 1.506 = a > A Go g g i 3 1.504 3 Y x00 = oa | 1.502 a = a 150 i ty 1.600 5 aA a ai Pa oc 5 a al wi 4498 i wl Leet 2 Ln La A 1,496 oc Pe | p th 1.494 0 1.492 60-40-20 0 20 40 60 80 100 120140 60 -40-20 0 20 49 60 80 100 120 149 TEM PERATURE (C) TEM PERATURE (C} MAXIMUM SWITCH ON-TIME vs. TEMPERATURE SHUTDOWN CURRENT vs. TEMPERATURE ~./ MAKT FO 13, MAXTTO- 12 Ny, g \ 2 16.0 \ = = 2 lec (WA) \ \ , Ve=4 -60 -30 0 30 #680 0 120 150 680 -40 -20 0 20 40 60 80 100 120 140 TEM PERATURE (C) TEM PERATURE (C} MAXIMUM SWITCH ON-TIME/ MINIMUM SWITCH CFF-TIME vs. MINIMUM SWITCH OFF-TIME RATIO TEMPERATURE vs. TEMPERATURE 2,30 2 8.0 e 3 z E 5 = = NY % 75 2 INQ 2 2 a5 ha / a b =" 25 <7 B70 9 = = Z 68 220 6.0 0-30 0 30 60 $0 120 150 60-80 0 30 80 90 120 160 TEMPERATURE (C) TEM PERATURE (C) MA AXLAA 5 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Typical Operating Characteristics (continued) (Circuit of Figure 2a, Ta = +25 C, unless otherwise noted.) MAX?70 MAX?770 HEAVY-LOAD SWITCHNG WAVEFORM S LIGHT-LOAD SWITCHING WAVEFORMS 20us/div 20us/div ViN=2.9, IquT=0.9A V+ =3V, Iquy = 165mA A: EXT VOLTAGE, 5V/div Ar EXT VOLTAGE 5VWdiv B: INDUCTOR CURRENT 1 A/div B: INDUCTOR CURRENT, 1 Aviv C: Vout RIPPLE 100mVidiv, AC-COQUPLED C. Voor RIPPLE 100mVidiv, AC-CQUPLED MAxX770 MAX770 LINE-TRANSIENT RESPONSE LOAD-TRANSIENT RESPONSE 45V 2.74 2msidiv 2msidiv lout = 0.7A Vin=3V A Vin, 27V TO4.5V, 2V/div A LOAD CURPENT 0.5A/div (0A to 1A) B: Vout RIPPLE, 100mV/div, AC-COUPLED B: VoUTRIPPLE, 100mV/div, AC-COUPLED 6 MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Typical Operating Characteristics (continued) (Circuit of Figure 2a, Ta = +25 C, unless otherwise noted.) MAX770 EXITING SHUTDOWN 200us/div Vin =S, louT= 0.54 AL SHDN, 2Walv B: Vout, 2Walv Pin Description PIN MAX770 NAME FUNCTION MAX771 | MAX773 MAX772 1 _ EXT Gate drive for external N-channel power transistor Power-supply input. Also acts as a voltage-sense point when in bootstrapped mode for the 2 3 V4 MAX770/MAX771/MAX772, or as a shunt regulator when SGND is connected to ground for the MAX?773. Bypass to SGND with 0.1pF when using the shunt regulator. 3 6 ER Feedback inp ut for adjustable-output operation. Connect to ground for fixed-output operation. Use a resistor divider network to adjust the output voltage. See Setting ithe Output Voliage section. Active-high TTL'GMQS logic-level shutdown input. In shutdown mode, Vout is a diode drop 4 7 SHDN below V+ (due to the DC path from V+ to the output) and the supply current drops to SA maximum. Gonnect to ground for normal operation. 1.5V reference output that can source 100nA for external loads. Bypass to GND with 0.1F. . 8 REF The reference is disabled in shutdown. 6 _ AGND | Analog ground 7 9 GND High-current ground return for the output driver 8 ml cs Positive input to the current-sense amplifier. Connect the current-sense resistor between CS and GND. Input sense point for 12V-output operation. Gonnect Vout to V12 for 12V-output operation. 1 V1i2 . : Leave unconnected for adjustable-output operation. _ 2 V5 Input sense point for 5V-output operation. Connect Vout to V5 for 5V-output operation. Leave unconnected for adjustable-output operation. _ 4 LRO Low-battery output is an open-drain output that goes low when LBI is less than 1.5V. Gonnect to V+ through a pull-up resistor. Leave floating if not used. LBO is high impedance in shutdown mode. _ 5 LBI Input to the internal low-battery comparator. Tie to GND or V+ if not used. _ 10 SGND | Shunt regulator ground. Leave unconnected if the shunt regulator is not used. MA AXIAA 7 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Pin Description (continued) PIN MAX770 MAX771 | MAX773 NAME FUNCTION MAX772 12 EXT Low-level gate/base drive for external power transistor. Connect to the gate of an external ~~ N-channel MOSFET or to the base of an external NPN transistor. High-level gate/base drive for external power transistor. Gonnect to EXTL when using an external _ 13 EXTH N-channel MOSFET. When using an external NPN transistor, connect a resistor RBAsE from EXTH to the base of the NPN to set the maximum base-drive current. Input sense point for 15V-output operation. Gonnect VouT to V15 for 15V-output operation. _ 14 V15 : : Leave unconnected for adjustable-output operation Detailed Description The MAX?770-MAX773 are BICMOS, step-up, switch- mode power-supply controllers that provide preset 5V, 12V, and 15V output voltages, in addition to adjustable- output operation. Their unique control scheme com- bines the advantages of pulse-frequency modulation (low supply current) and pulse-width modulation (high efficiency with heavy loads), providing high efficiency over a wide output current range, as well as increased output current capability over previous PFM devices. In addition, the external sense resistor and power transistor allow the user to tailor the output current capability for each application. Figure 1 shows the MAX770-MAX773 block diagram. The MAX770-MAX/73 offer three main improvements over prior pulse-skipping control solutions: 1) the con- verters operate with tiny (6mm height and less than 9mm diameter) surface-mount inductors due to their 300kHz switching frequency; 2) the current-limited PFM control scheme allows 87% efficiencies over a wide range of load currents; and 3) the maximum supply current is only 110yA. The MAX?773 can be configured to operate from an internal 6V shunt regulator, allowing very high input/out- put voltages. Its output can be configured for an adjustable voltage or for one of three fixed voltages (BV, 12V, or 15V), and it has a power-fail comparator for low-battery detection. All devices have shutdown capability, reducing the supply current to 5uA max. Bootstrapped/Non-Bootstrapped Modes Figures 2 and 3 show standard application circuits for bootstrapped and non-bootstrapped modes. In boot strapped mode, the IC is powered from the output (VOUT, which is connected to V+) and the input voltage range is 2V to VouT. The voltage applied to the gate of the external power transistor is switched from VOUT to ground, providing more switch gate drive and thus reducing the transistors on resistance. In non-bootstrapped mode, the IC is powered from the input voltage (V+) and operates with minimum supply current. In this mode, FB is the output voltage sense point. Since the voltage swing applied to the gate of the external power transistor is reduced (the gate swings from V+ to ground), the power transistors on resistance increases at low input voltages. However, the supply current is also reduced because V+ is at a lower volt- age, and because less energy is consumed while charging and discharging the external MOSFETs gate capacitance. The minimum input voltage for the MAX770-MAX773 is 3V when using external feedback resistors. With supply voltages below 5V, bootstrapped mode is recommended. Note: When using the MAX770/MAX771/MAX772 in non-bootstrapped mode, there is no preset output operation because V+ is also the output voltage sense point for fixed-output operation. External resistors must be used to set the output voltage. Use 1% external feedback resistors when operating in adjustable-output mode (Figures 2c, 2d, 3b, 3d, 3e) to achieve an overall output voltage accuracy of +5%. The MAX773 can be operated in non-bootstrapped mode without using external feedback resistors because V+ does not act as the output voltage sense point with preset-output operation. To achieve high- est efficiency, operate in bootstrapped mode when- ever possible. MAX773 Shunt-Regulator Operation The MAX773 has an internal 6V shunt regulator that allows the device to step up from very high input voltages (Figure 4). MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low 1!Q, Step-Up DC-DC Controllers : COMPARATOR MAX770-MAX773 SHDN BIAS CIRCUITRY ee LOW. VOLTAGE | I |} OSCILLATOR ee | ONE-SHOT CUPRENT- SENSE AMPLIFIER Figure 1. Block Diagram Floating the shunt-regulater ground (SGND) disables the shunt regulator. To enable it, connect SGND to GND. The shunt regulator requires 1mA minimum cur- rent for proper operation; the maximum current must not exceed 20mA. The MAX773 operates in non-boot- strapped mode when the shunt regulator is used, and EXT swings between the 6V shunt-requlator voltage and GND. When using the shunt regulator, use an N-channel pow- er FET instead of an NPN power transistor as the power switch. Otherwise, excessive base drive will collapse the shunt regulator. MA AXIAA External Power-Transistor Control Circuitry PFM Control Scheme The MAX770-MAX773 use a proprietary current-limited PFM control scheme to provide high efficiency over a wide range of load currents. This control scheme com- bines the ultra-low supply current of PFM converters (or pulse skippers) with the high full-load efficiency of PWM converters. Unlike traditional PFM converters, the MAX770- MAX773 use a sense resistor to control the peak induc- tor current. They also operate with high switching EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Vin =3V te L OF 2 = V+ ST REF 3 | MNMAXLAA ON, MAX770 SHDN iB EXT 84 acnp GND Vin = 5V toe L O.1uF 2 = V+ 5] per C1 . c3_| MAXIMA SBF -T~ O.1pF 4 SHON MAX?71 - Vout = 12 @0.5A 3 + FB EXT Si9410DY 4 acnp Cs Pornse owt C4 GND 10072 T* 200uF |7 Figure 2a. 5V Preset Outout, Bootsirapped Vin=5 I L4 R Vout = 12 qf MAXLA SHDN MANTT1 EXT AGND cs Vout Re=(R1)( -1) = ( ie ) Vag = 1.5V Vin=4V re =a (7 4) = Var = 1.57 Figure 2c. 12V Quiput, Non-Bootstrapp ed frequencies (up to 300kHz), allowing the use of tiny external components. As with traditional PFM converters, the power transistor is not turned on until the voltage comparator senses that the output is out of regulation. However, unlike tra- ditional PFM converters, the MAX770-MAX773 switch using the combination of a peak current limit and a pair of one-shots that set the maximum on-time (16s) and 10 Figure 2d. 9V Output, Bootsirapped minimum off-time (2.3us); there is no oscillator. Once off, the minimum off-time one-shot holds the switch off for 2.3us. After this minimum time, the switch either 1) stays off if the output is in regulation, or 2) turns on again if the output is out of regulation. The control circuitry allows the ICs to operate in contin- uous-conduction mode (CCM) while maintaining high efficiency with heavy loads. When the power switch is MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers ds Te p VIN am vig = V5 v5 sqnp Lo Li sak MAXLA 29\1H PEF sy MAX773 wol4 ot | Vout =12 LBI FS tne SHDN +o ("9 r Fe eax q Vor (V) - MIN TNOWINAL TAK] yp ( MTP 1) 106 | 11.0 11.4 VREF VRE = 1.5V Vin =5V cl a C2 { H D1 Vout = 24 as] = 47uF T Lote HW 1N5818 @ 30mA = _= 3 V+ 10] send ; o_o _|n| qi = < LB SHDN , pe = ty (71) _ Vac = 1.5 Figure 3a. 12V Preset Outout, Bootsirapped, N-Channel Power MOSFET Figure 3b. 24V Output, Non-Booistrapped, NPN Power Transistor Di 1N5817 Vayt = 15 10} scnp** 41 tbo EXTL 8) ee cs [cs MAXLAA 0.1pF vis L14 = viz EL v5 FZ Vout = 16V 4] Leo [os MAXIAA OTF MAX773 Stig SHDN SGND Figure 3c. 15V Preset Output, Non-Bootsirapped N-Channel Power MOSFET MA AXIAA Figure 3d. 16V Output Booisiraoped, N-Channel Power MOSFET 11 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Vin = 24 TO 28V DI - MURI15 Youre von O1uF 10) can =_Al LBo EXTL a cs | 3 MAXIM =o.1uF max773 Vis L'4 5 iB we LL v5 12 = FR ; 732k (1%) SHON ref GND 11.3 (1%) Your 4 Po = (Rt) (27 4 (er) a Veer = 1.5 VIN PeHUNT MAXLAA MAX773 8Y (typ) J O.1uF 7 (ye) a 10 | SGND Vin iain > YgHuNT (MAX) PRSHUNT = _____ | SHUNT SEE TEXT FOR I sHunT CALCULATION Figure 3e. 100V Quiput, Shunt Regulator, N-Channel Power MOSFET turned on, it stays on until either 1) the maximum on- time one-shot turns it off (typically 16us later), or 2) the switch current reaches the peak current limit set by the current-sense resistor. To increase light-load efficiency, the current limit for the first two pulses is set to one-half the peak current limit. If those pulses bring the output voltage into regulation, the error comparator holds the MOSFET off and the current limit remains at one-half the peak current limit. If the output voltage is still out of regulation after two pulses, the current limit for the next pulse is raised to the peak current limit set by the external sense resistor (see inductor current waveforms in the Typical Operating Characteristics). The MAX770-MAX/773 switching frequency is variable (depending on load current and input voltage), causing variable switching noise. However, the subharmonic noise generated does not exceed the peak current limit times the filter capacitor equivalent series resistance (ESR). For example, when generating a 12V output at 500mA from a 5V input, only 180mvV of output ripple occurs using the circuit of Figure 2b. 12 Figure 4. MAX773 Shunt Regulator Low-Voltage Start-Up Oscillator The MAX7/0/MAX?771/MAX772 feature a low input volt- age start-up oscillator that guarantees startup with no load down to 2V when operating in bootstrapped mode and using internal feedback resistors. At these low volt- ages, the supply voltage is not large enough for proper error-comparator operation and internal biasing. The start-up oscillator has a fixed 50% duty cycle and the MAX770/MAX771/MAX772 disregard the error-com- parator output when the supply voltage is less than 2.5V. Above 2.5V, the error-comparator and normal one- shot timing circuitry are used. The low voltage start-up circuitry is disabled if non-bootstrapped mode is select- ed (FB is not tied to ground). The MAX773 does not provide the low-voltage 50% duty-cycle oscillator. Its minimum start-up voltage is 3V for all modes. External Transistor An N-FET power switch is recommended for the MAX770/MAX?77 1/MAX772. The MAX773 can drive either an N-channel MOSFET (N-FET) or an NPN because it provides two separate MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers drive outputs (EXTH and EXTL} that operate 180 out of phase (Figures 3a and 3b). In Figure 3b, the resistor in series with EXTH limits the base current, and EXTL (which is connected directly to the base) turns the transistor off. Shutdown Mode When SHDN is high, the MAX770-MAX773 enter shut down mode. In this mode, the internal biasing circuit- ry is turned off (including the reference) and VauUT falls to a diode drop below Vin (due to the DC path from the input to the output). In shutdown mode, the supply current drops to less than 5uA. SHDN is a TTILICMOS logic-level input. Connect SHDN to GND for normal operation. The MAX773s shunt regulator is not disabled in shut- down mode. Low-Battery Detector The MAX773 provides a low-battery comparator that compares the voltage on LBI to the reference voltage. When the LBI voltage is below VREF, LBO (an open- drain output) goes low. The low-battery comparator's 20mV of hysteresis adds noise immunity, preventing repeated triggering of LBO. Use a resistor-divider network between V+, LBI, and GND to set the desired trip voltage VTRIP. LBO is high impedance in shutdown mode. Design Procedure Setting the Output Voltage To set the output voltage, first determine the mode of operation, either bootstrapped or non-bootstrapped. Bootstrapped mode provides more output current capability, while non-bootstrapped mode reduces the supply current (see Typical Operating Characteristics). If a decaying voltage source (such as a battery) is used, see the additional notes in the Low Input Voltage Operation section. Use the MAX?770/MAX771/MAX77e unless one or more of the following conditions applies. If one or more of the following is true, use the MAX773: 1) An NPN power transistor will be used as the power switch 2) The LBI/LBO function is required 3) The shunt regulator must accommodate a high input voltage 4) Preset-output non-bootstrapped operation is desiredfor example, to reduce the no-load supply current in a 5V to 12V application. MA AXIAA Re FB Vout MA AXLAA MAX770 Rt MAX771 MAX772 + MAX?73 Ri = 10k TO 500k GND Fe= Ri (Yor -1) T vs = Veer = 1.5 Figure 5. Adjustable Output Circuit See Table 1 for a summary of operating characteristics and requirements for the ICs in bootstrapped and non- bootstrapped modes. The MAX770-MAX773's output voltage can be adjust- ed from very high voltages down to 3V, using external resistors R1 and R2 configured as shown in Figure 5. For adjustable-output operation, select feedback resis- tor R1 in the range of 10k to 500k. R2 is given by: R2 = (RI) (Your) where VREF equals 1.5V. For preset-output operation, tie FB to GND (this forces bootstrapped-mode operation for the MAX? 7O/MAX771/MAX772}. Configure the MAX773 for a preset voltage of 5V, 12V, or 15V by connecting the output to the corresponding sense input pin (i.e., V5, V12, or V15). FB must be tied to ground for preset-output operation. Leave all unused sense input pins unconnected. Failure to do so will cause an incorrect output voltage. The MAX773 can provide a preset output voltage in both bootstrapped and non- bootstrapped modes. Figures 2 and 3 show various circuit configurations for bootstrapped/non-bootstrapped, preset/adjustable operation. Shunt-Regulator Operation When using the shunt regulator, connect SGND to ground and place a 0.1uF capacitor between V+ and SGND, as close to the IC as possible. Increase G2 to 1.0UF to improve shunt regulators performance with heavy loads. Select RSHUNT such that 1mA < ISHUNT < 20mA. 13 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Table 1. Bootstrapped vs. Non-Bootstrapped Operation PARAMETER BOOTSTRAPPED* NON-BOOTSTRAPPED Gate Drive GND to Vout GND to V+ FET On Resistance Lower Higher Gate-Drive Capacitive Losses Higher Lower No-Load Supply Current Higher Lower 2V to 16.5V (MAX770/MAX771/MAX772)}, (internal feedback resistors) 3V to 16.5V Possible Input Voltage Range 3V to 16.5V (MAX770/MAX?771/MAX?772)}, (MAX770/MAX771/MAX772), (external feedback resistors) 3V to 16.5V (MAX773) 3V and up (MAX773) BV to 16.5V Voltage Range Input NY r ey MAX) (MAX770/MAX771 /MAX772), 5V and up (MAX773) Fixed Output Available MAX770-MAX773(N) MAX773(N)/MAX773(S) . . MAX?770/MAX771/MAX772/ Adjustable Output Available MAX770-MAX773(N) MAX773(N\/MAX773(S) *MAX773(S} indicates shunt mode; MAX773(N) indicates NOT in shunt mode. Use an N-channel FET as the power switch when using the shunt regulator (see MAX773 Shunt-Regulator Operation in the Detailed Description). The shunt-regu- lator current powers the MAX773 and also provides the FET gate-drive current, which depends largely on the FETs total gate charge at Vas = 5V. To determine the shunt-resistor value, first determine the maximum shunt current required. ISHUNT = ISUPP + IGATE See N-Channel MOSFETs in the Power-Transistor Selection section to determine IGATE. Determine the shunt-resistor value using the following equation: Vin(min) - VSHUNT(max) RSHUNT(Max) = _ ISHUNT where VSHUNT(Mmax) is 6.3V. The shunt regulator is not disabled in shutdown mode, and continues to draw the calculated shunt current. If the calculated shunt regulator current exceeds 20mA, or if the shunt current exceeds 5mA and less shunt reg- ulator current is desired, use the circuit of Figure 6 to provide increased drive and reduced shunt current when driving N-FETs with large gate capacitances. Select ISHUNT = 3mA. This provides adequate biasing current for this circuit, although higher shunt currents can be used. 14 Figure 6. Increased N-FET Gate Drive when Using the Shunt Regulator To prevent the shunt regulator from drawing current in shutdown mode, place a switch in series with the shunt resistor. MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers 35 ony _ 39 PLEZHH a a5] Pease= ro. a fe Feevse= Samo) Cn 3 29 Pad - Reayge=75n0] E 15 LA > it 5 o Cm _ % Poayge= 100m02 05 ma | , 3 4 5 INPUT VOLTAGE() 35 Vour= 12V Fa 30 E = 22\H | = Peaee< ren) i a 25 - Peense=50mO._ fA ft ' of e 20 vd Z & a 15 A : a a] = 10 = Lo > Peayse = 100ma. = 05 Cea ae . _2a I = Penge = 20078 2 4 6 8 10 12 INPUT VOLTAGE (V) Figure 7a. Maximum Output Current vs. input Voltage (VouT = 5V) Figure 7b. Maximum Output Current vs. input Voltage = 100ma MAXIMUM OUTPUT CURRENT (A) Peense = 200722 2 4 6 8 102 14 16 INPUT VOLTAGE (V) 08 (Vout = 12V) Feense= 10070 Peense = 20022 wn Reense= 400m 10 14 a NM, MAXIMUM CUTPUT CURRENT (A) So B = INPUT VOLTAGE (V) Figure 7c. Maximum Output Current vs. Input Voltage (VouT= 15V) Determining RSENSE The Typical Operating Characteristics graphs show the output current capability for various modes, sense resistors, and input/output voltages. Use these graphs, along with the theoretical output current curves shown in Figures 7a-7d, to select RSENSE. These theoretical curves assume that an external N-FET power switch is used. They were derived using the minimum (worst- case) current-limit comparator threshold value, and the inductance value. No tolerance was included for RSENSE. The voltage drop across the diode was assumed to be 0.5V, and the drop across the power switch rDs(ON) and coil resistance was assumed to be 0.38V. To use the graphs, locate the graph with the appropriate output voltage or the graph having the nearest output voltage higher than the desired output voltage. On this graph, find the curve for the largest MA AXIAA Figure 7d. Maximum Output Current vs. Input Voltage (VouT = 24V) sense-resistor value with an output current that is ade- quate at the lowest input voltage. Determining the Inductor (L) Practical inductor values range from 10uH to 300uH. 20H is a good choice for most applications. In appli- cations with large input/output differentials, the ICs output current capability will be much less when the inductance value is too low, because the IC will always operate in discontinuous mode. If the inductor value is too low, the current will ramp up to a high level before the current-limit comparator can turn off the switch. The minimum on-time for the switch (ton(min)) is approximately 2us; select an inductor that allows the current to ramp up to ILIM/2 in no less than 2us. Choosing a value of ILIM/2 allows the half-size current pulses to occur, increasing light-load efficiency and minimizing output ripple. 15 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers ANAXIAA MAX770 MAX771 MAX772, | @ PE --- cs Peense low MAXIM ras MAX773 IB Poase NPN Reense Figure 8a. Use an N-Channel MOSFET with the MAX?770/MAX771/MAX?772 MAXIM MAX773 Figure 8b. Using an N-Channel MOSFET with the MAX773 The standard operating circuits use a 22uH inductor. lf a different inductance value is desired, select L such that: > Vin(max) x ton(min} - ILim/2 Larger inductance values tend to increase the start-up time slightly, while smaller inductance values allow the coil current to ramp up to higher levels before the switch turns off, increasing the ripple at light loads. Inductors with a ferrite core or equivalent are recom- mended; powder iron cores are not recommended for use with high switching frequencies. Make sure the inductors saturation current rating (the current at which the core begins to saturate and the inductance starts to fall) exceeds the peak current rating set by RSENSE. However, it is generally acceptable to bias the inductor inte saturation by approximately 20% (the point where the inductance is 20% below the nominal value). For highest efficiency, use a coil with low DC resistance, 16 Figure 8c. Using an NPN Transisior with the MAX773 preferably under 20mQ. To minimize radiated noise, use 4 toroid, a pot core, or a shielded coil. Table 2 lists inductor suppliers and specific recom- mended inductors. Power Transistor Selection Use an N-channel MOSFET power transistor with the MAX770/MAX?77 1/MAX77e2 (Figure 8a). Use an N-FET whenever possible with the MAX773. An NPN transistor can be used, but be extremely careful when determining the base current (see NPN Transistors section). An NPN transistor is not recom- mended when using the shunt regulator. N-Channel MOSFETs To ensure the external N-channel MOSFET (N-FET) is turned on hard, use logic-level or low-threshold N-FETs when the input drive voltage is less than 8V. This applies even in bootstrapped mode, to ensure start-up. N-FETs provide the highest efficiency because they do not draw any DC gate-drive current, but they are typi- cally more expensive than NPN transistors. When using an N-FET with the MAX?773, connect EXTH and EXTL to the N-FETs gate (Figure 8b). When selecting an N-FET, three important parameters are the total gate charge (Qqg), on resistance (rDSfON)), and reverse transfer capacitance (CRgs). Qg takes into account all capacitances associated with charging the gate. Use the typical Gg value for best results; the maximum value is usually grossly over- specified since it is a guaranteed limit and not the mea- sured value. The typical total gate charge should be 50nC or less. With larger numbers, the EXT pins may not be able to adequately drive the gate. The EXT rise/fall time with various capacitive loads as shown in the Typical Operating Characteristics. MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers The two most significant losses contributing to the N-FETs power dissipation are |2R losses and switching losses. Select a transistor with low rpsjon) and low CRss to minimize these losses. Determine the maximum required gate-drive current from the Qg specification in the N-FET data sheet. The MAX773s maximum allowed switching frequency during normal operation is 8300kHz; but at start-up the maximum frequency can be 500kHz, so the maximum current required to charge the N-FETs gate is f(max) x Qg(typ). Use the typical Qg number from the transistor data sheet. For example, the Si9410DY has a Qag(typ) of 17nG (at Vas = 5V), therefore the current required to charge the gate is: IGATE (max) = (500kHz) (17nC) = 8.5mA. The bypass capacitor on V+ (C2) must instantaneously furnish the gate charge without excessive droop (e.g., less than 200mV): Q AV+ = ot Ge Continuing with the example, AV+ = 17nC/O.1pF = 170mvV. Use IGATE when calculating the appropriate shunt resistor. See the Shunt Regulator Operation section. Figure 2as application circuit uses an MTD3055EL logic-level N-FET with a guaranteed threshold voltage (VTH) of 2V. Figure 2bs application circuit uses an 8-pin Si9410DY surface-mount N-FET that has 50m& on resistance with 4.5V Ves, and a guaranteed VTH of less than 3V. NPN Transistors The MAX773 can drive NPN transistors, but be extremely careful when determining the base-current requirements. Too little base current can cause exces- sive power dissipation in the transistor; too much base current can cause the base to oversaturate, so the tran- sistor remains on continually. Both conditions can dam- age the transistor. When using the MAX773 with an NPN transistor, con- nect EXTL to the transistor's base, and connect RBASE between EXTH and the base (Figure 8c). To determine the required peak inductor current, IC{PEAK}, observe the Typical Operating Characteristics efficiency graphs and the theoretical output current capability vs. input voltage graphs to determine a sense resistor that will allow the desired output current. Divide the 170mV worst-case (smallest) voltage across the current-sense amplifier Vcs(max) by the sense- resistor value. To determine Ip, set the peak inductor current (ILIM) equal to the peak transistor collector cur- MA AXIAA rent Ic(PEAK}. Calculate IB as follows: Ip = ILIM/B Use the worst-case (lowest) value for B given in the transistors electrical specification, where the collector current used for the test is approximately equal to ILIM. It may be necessary to use even higher base currents (e.g., IB = ILIM/10), although excessive IB may impair operation by extending the transistors turn-off time. RBASE is determined by: (VEXTH - VBE - Vos(min)) RBASE = Ig Where VEXTH is the voltage at V+ (in bootstrapped mode VEXTH is the output voltage), VBE is the 9.7V transistor base-emitter voltage, Vcg(min) is the voltage drop across the current-sense resistor, and Ip is the minimum base current that forces the transistor into saturation. This equation reduces to (V+ - 700mV - 170mV} / IB. For maximum efficiency, make RBASE as large as pos- sible, but small enough to ensure the transistor is always driven near saturation. Highest efficiency is obtained with a fast-switching NPN transistor (fT = 150MHz) with a low collector-emitter saturation voltage and a high current gain. A good transistor to use is the Zetex ZTX694B. Diode Selection The MAX770-MAX/773's high switching frequency demands a high-speed rectifier. Schottky diodes such as the 1N5817-1N5822 are recommended. Make sure that the Schottky diodes average current rating exceeds the peak current limit set by RSENSE, and that its breakdown voltage exceeds VouT. For high-temper- ature applications, Schattky dicdes may be inadequate due to their high leakage currents; high-speed silicon diodes may be used instead. At heavy loads and high temperatures, the benefits of a Schottky diodes low for- ward voltage may outweigh the disadvantages of its high leakage current. Capacitor Selection Output Filter Capacitor The primary criterion for selecting the output filter capacitor (C2) is low effective series resistance (ESR). The product of the peak inductor current and the output filter capacitors ESR determines the amplitude of the ripple seen on the output voltage. An OS-CON 300LF, 6.3V output filter capacitor has approximately 50mQ of ESR and typically provides 180mV ripple when stepping up from 3V to 5V at 1A (Figure 2a). 17 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Smaller capacitors are acceptable for light loads or in applications that can tolerate higher output ripple. Since the output filter capacitors ESR affects efficien- cy, use low-ESR capacitors for best performance. The smallest low-ESR surface-mount tantalum capacitors currently available are the Sprague 595D series. Sanyo O&-CON organic semiconductor through-hole capaci- tors and the Nichicon PL series also exhibit low ESR. See Table 2. input Bypass Capacitors The input bypass capacitor (C1} reduces peak currents drawn from the voltage source and also reduces noise at the voltage source caused by the switching action of the MAX770-MAX773. The input voltage source imped- ance determines the size of the capacitor required at the V+ input. As with the output filter capacitor, a low- ESR capacitor is recommended. For output currents up to 1A, 150uF (C1) is adequate, although smaller bypass capacitors may also be acceptable. Bypass the IC with a 0.1uF ceramic capacitor (C2) placed close to the V+ and GND pins. Reference Capacitor Bypass REF with a 0.1uF capacitor (C3). REF can source Up to 100A of current. Setting the Low-Battery-Detector Voltage To set the low-battery detectors falling trip voltage (VTRIP(falling)}, select R8 between 10k and 500kQ (Figure 9}, and calculate R4 as follows: VTRIP - VREF ) R4 = (R3) ( = where VREF = 1.5V. The rising trip voltage is higher because of the com- parators approximately 20mV of hysteresis, and is determined by: is R4 VTRIP (rising) = (VREF + 20m) (1 + Ra) Connect a high value resistor (larger than R3 + R4) between LBI and LBO if additional hysteresis is required. Connect a pull-up resistor (e.g., 100k&) between LBO and V+. Tie LBI to GND and leave LBO floating if the low-battery detector is not used. 18 VIN Vt JVLAXLAA = GND witty) = RRC 1) Vag = 1.5V Figure 9. Input Voliage Monitor Circuit Applications Information MAX773 Operation with High Input/Output Voltages The MAX?773s shunt regulator input allows high volt- ages to be converted to very high voltages. Since the MAX773 runs off the 6V shunt (bootstrapped operation is not allowed), the IC will not see the high input volt- age. Use an external logic-level N-FET as the power switch, since only 6V of V@s are available. Also, make sure all external components are rated for very high output voltage. Figure 3e shows a circuit that converts 28V to 100V. Low Input Voltage Operation When using a power supply that decays with time (such as a battery), the N-FET transistor will operate in its linear region when the voltage at EXT approaches the threshold voltage of tne FET, dissipating excessive power. Prolonged operation in this mode may damage the FET. This effect is much more significant in non- bootstrapped mode than in bootstrapped mode, since bootstrapped mode typically provides much higher Vas voltages. To avoid this condition, make sure VExT is above the VTH of the FET, or use a voltage detector (such as the MAX8211) to put the IC in shutdown mode once the input supply voltage falls below a predeter- mined minimum value. Excessive loads with low input voltages can also cause this condition. MAXIMA5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers Starting Up under Load The Typical Operating Characteristics show the Start- Up Voltage vs. Load Current graph for bootstrapped- mode operation. This graph depends on the type of power switch used. The MAX770-MAX773 are not designed to start up under full load in boot- strapped mode with low input voltages. Layout Considerations Due to high current levels and fast switching wave- forms, which radiate noise, proper PC board layout is essential. Protect sensitive analog grounds by using a star ground configuration. Minimize ground noise by connecting GND, the input bypass capacitor ground Table 2. Component Suppliers lead, and the output filter capacitor ground lead to a single point (star ground configuration). Also, minimize lead lengths to reduce stray capacitance, trace resis- tance, and radiated noise. Place input bypass capaci- tor C2 as close as possible to V+ and GND. Excessive noise at the V+ input may falsely trigger the timing circuitry, resulting in short pulses at EXT. If this occurs it will have a negligible effect on circuit efficien- cy. If desired, place a 4.7uF directly across the V+ and GND pins (in parallel with the 0.1WF C2 bypass capaci- tor) to reduce the noise at V+. PRODUCTION INDUCTORS CAPACITORS TRANSISTORS DIODES N-FET Sumida Matsuo Siliconix CD54 series 267 series $19410DY Nihon Surface Mount CDR125 series SiS420DY (high voltage) EC10 seri Coiltronics Spragie . Motorola series CTX20 series Series MTP3055EL MTD20N03HDL . Sanyo Sumida . RCH855 series Nona Series NPN Motorola Through Hole RGH110 series PL series Zetex 1N5817-1N5822 Renco . : Z1X694B MUR115 (high voltage) United Chemi-Con RL1284-18 : LXF series SUPPLIER PHONE FAX Goiltronics USA: (561) 241-7876 (561) 241-9339 Matsuo USA: (714) 969-2491 (714) 960-6492 Japan: 81-6-337-6450 81-6-337-6456 Nichicon USA: (847) 843-7500 (847) 843-2798 Nihon USA: (805) 867-2555 (805) 867-2698 Renco USA: (516) 586-5566 (516) 586-5562 Sanyo USA: (619) 661-6835 (619) 661-1055 Japan: 81-7-2070-6306 81-7-2070-1174 Sumida USA: (847) 956-0666 Japan: 81-3-3607-5111 81-3-3607-5144 United Chemi-Con USA: (714) 255-9500 (714) 255-9400 Zetex USA: (516) 543-7100 (516) 864-7630 UK: 44-61-627-4963 44-61-627-5467 MA AXIAA 19 EZZLXVNW-OLZXVINMAX770-VMAX773 5V/12V/15V or Adjustable, High-Efficiency, Low !1Q, Step-Up DC-DC Controllers ___Ordering Information (continued) PART TEMP. RANGE PIN-PACKAGE MAX771CPA 0T to +70 8 Plastic DIP MAX771CSA OT to +70 8 SO MAX?71G/D 0T to +70T Dice* MAX771EPA 40 to +85 8 Plastic DIP MAX771ESA 40 to +85 8 So MAX?771MJA 55 to +125 8 CERDIP MAX772CPA OT to 4+70T 8 Plastic DIP MAX?72CSA 0 to +70T 8 SO MAX772C/D OT to 4+70T Dice* MAX? 72EPA 40 to +85 8 Plastic DIP MAX?72ESA 40T to +85 8S0 MAX772MJA 55 to 4125 8 CERDIP MAX773CPD 0T to +70T 14 Plastic DIP MAX773CSD OT to 4+70T 14 S80 MAX?73C/D 0T to +70T Dice* MAX773EPD 40% to +85 14 Plastic DIP MAX773ESD 40 to +85 14 Narrow SO MAX773MJD 55 to 4125 14 CERDIP *Contact factory for dice specifications. Pin Configurations (continued) TOP VIEW . = viz [A] a] vis vs [2 3] EXTH [3| anaxiaa [2] 21 LBO| 4 MAx773,_ [i] cs Lei [| Ho] SeND Ble Eley) SHDN [7 | 3] REF DIP/SO 20 Chip Topographies MAX770/MAX771/MAX772 EXT 0.126" (3.200mm) FB SHDN 080" (2.032mm) TRANSISTOR GOUNT: 501; SUBSTRATE CONNECTED TO V+. MAX773 V5 W12 Vib V+ LBO cs SGND LBI 0.126" (3,.200mm) GND FB GND (2.032mm) TRANSISTOR GOUNT: 501; SUBSTRATE CONNECTED TO V+. MAXIMA