MAX1705/MAX1706 19-1198 Rev 1 8/00 1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator General Description Features The MAX1705/MAX1706 are high-efficiency, low-noise, Up to 96% Efficiency step-up DC-DC converters with an auxiliary linear- 1.1V Guaranteed Startup IN regulator output. These devices are intended for use in Up to 850mA Output (MAX1705) battery-powered wireless applications. They use a syn- chronous rectifier pulse-width-modulation (PWM) boost Step-Up Output (2.5V to 5.5V Adjustable) topology to generate 2.5V to 5.5V outputs from battery Linear Regulator (1.25V to 5.0V Adjustable) inputs, such as 1 to 3 NiCd/NiMH cells or 1 Li-Ion cell. The MAX1705 has an internal 1A n-channel MOSFET PWM/PFM Synchronous-Rectified Topology switch. The MAX1706 has a 0.5A switch. Both devices 300kHz PWM Mode or Synchronizable also have a built-in low-dropout linear regulator that delivers up to 200mA. 1A Shutdown Mode With an internal synchronous rectifier, the MAX1705/ Voltage Monitor MAX1706 deliver 5% better efficiency than similar non- Pushbutton On/Off Control synchronous converters. They also feature a pulse- frequency-modulation (PFM) standby mode to improve efficiency at light loads, and a 1A shutdown mode. An Ordering Information efficiency-enhancing track mode reduces the step-up DC-DC converter output to 300mV above the linear-reg- PART TEMP RANGE PIN-PACKAGE ulator output. MAX1705C/D 0C to +70C Dice* Both devices come in a 16-pin QSOP package, which MAX1705EEE -40C to +85C 16 QSOP occupies the same space as an 8-pin SO. Other features MAX1706C/D 0C to +70C Dice* include two shutdown-control inputs for push-on/push-off MAX1706EEE -40C to +85C 16 QSOP control, and an uncommitted comparator for use as a volt- *Dice are tested at T = +25C, DC parameters only. A age monitor. Applications Typical Operating Circuit Digital Cordless Phones PCS Phones Personal Communicators Wireless Handsets INPUT 0.7V TO 5.5V Palmtop Computers Two-Way Pagers Handheld Instruments LX STEP-UP OUTPUT LBP Pin Configuration POUT LOW-BATTERY OUT DETECTION TOP VIEW FB MAX1705 LBP 1 16 POUT LBO MAX1706 LBN 2 15 ONA ON/OFF CONTROL ONA LINEAR ONB REF 3 14 ONB REGULATOR HIGH LOW OUTPUT CLK/SEL TRACK 4 MAX1705 13 LX EFFICIENCY NOISE LDO TRACK MAX1706 GND 5 12 PGND FBLDO LBN OUT 6 11 CLK/SEL REF GND PGND FB 7 10 LBO FBLDO 8 9 LDO QSOP Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. EVALUATION KIT AVAILABLE1- to 3-Cell, High-Current, Low-Noise, Step-Up DC-DC Converters with Linear Regulator ABSOLUTE MAXIMUM RATINGS ONA, ONB, FBLDO, OUT, POUT to GND...................-0.3V to 6V Continuous Power Dissipation (T = +70C) A PGND to GND.....................................................................0.3V QSOP (derate 8.70mW/C above +70C)...................696mW POUT to OUT......................................................................0.3V Operating Temperature Range ...........................-40C to +85C LX to PGND ............................................-0.3V to (V + 0.3V) Junction Temperature......................................................+150C POUT Storage Temperature Range .............................-65C to +160C CLK/SEL, REF, FB, TRACK, LDO, Lead Temperature (soldering, 10s) .................................+300C LBN, LBP, LBO to GND.......................-0.3V to (V + 0.3V) OUT LDO Short Circuit .......................................................Continuous Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions 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 = V = V = 3.6V, CLK/SEL = FB = LBN = LBO = ONA = ONB = TRACK = GND, REF = open (bypassed with 0.22F), OUT POUT LBP LX = open, T = 0C to +85C, unless otherwise noted. Typical values are at T = +25C.) A A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS DC-DC CONVERTER Minimum Startup Voltage T = +25C, I < 1mA, Figure 2 0.9 1.1 V A LOAD Minimum Operating Battery (Note 1) 0.7 V Voltage FB Regulation Voltage CLK/SEL = OUT 1.219 1.233 1.247 V FB Input Current V = 1.5V 0.01 50 nA FB OUT Adjust Range 2.5 5.5 V MAX1705, 0A I 0.5A LX Load Regulation MAX1706, 0A I 0.25A 0.65 1.25 % LX CLK/SEL = OUT V V V LDO LDO LDO OUT Voltage in Track Mode TRACK = V > 2.3V V LDO + 0.2 + 0.3 + 0.4 Frequency in Startup Mode f V = V = 1.5V 40 150 300 kHz LX POUT OUT Startup to Normal Mode (Note 2) 2.00 2.15 2.30 V Transition Voltage Supply Current in Shutdown I ONA = GND, ONB = OUT, measure I 120 A OUT OUT Supply Current in CLK/SEL = GND, V = V = 1.5V, FB FBLDO I 100 190 A OUT Low-Power Mode no load V = V = 1.5V, no load 180 360 A FB FBLDO Supply Current in I CLK/SEL = OUT OUT Low-Noise Mode FB = GND (LX switching) 2.1 mA REFERENCE Reference Output Voltage I = 0A 1.238 1.250 1.262 V REF Reference Load Regulation -1A < I < 50A 415 mV REF Reference Supply Regulation 2.5V < V < 5.5V 0.2 5 mV OUT 2 MAX1705/MAX1706