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EVALUATION KIT AVAILABLE
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters
General Description
The MAX1674/MAX1675/MAX1676 compact, high-efficiency, step-up DC-DC converters fit in small µMAX packages. They feature a built-in synchronous rectifier, which improves efficiency and reduces size and cost by eliminating the need for an external Schottky diode. Quiescent supply current is only 16µA.
The input voltage ranges from 0.7V to VOUT, where VOUT can be set from 2V to 5.5V. Start-up is guaranteed from 1.1V inputs. The MAX1674/MAX1675/ MAX1676 have a preset, pin-selectable output for 5V or 3.3V. The outputs can also be adjusted to other voltages using two external resistors.
All three devices have a 0.3Ω N-channel MOSFET power switch. The MAX1674 has a 1A current limit. The MAX1675 has a 0.5A current limit, which permits the use of a smaller inductor. The MAX1676 comes in a 10-pin µMAX package and features an adjustable current limit and circuitry to reduce inductor ringing.
________________________Applications
Pagers
Wireless Phones
Medical Devices
Hand-Held Computers
PDAs
RF Tags
1 to 3-Cell Hand-Held Devices
Functional Diagrams Typical Operating Circuit
INPUT 0.7V TO VOUT
ON OFF
SHDN
LX
MAX1674 OUT MAX1675
OUTPUT 3.3V, 5V, OR ADJ (2V TO 5.5V) UP TO 300mA
LOW-BATTERY DETECT IN
LBI LBO REF FB GND
LOW-BATTERY DETECT OUT
Pin Configuration0s.1µaFppear at end of data sheet. Functional Diagrams continued at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc.
____________________________Features
o 94% Efficient at 200mA Output Current o 16µA Quiescent Supply Current o Internal Synchronous Rectifier (no external diode) o 0.1µA Logic-Controlled Shutdown o LBI/LBO Low-Battery Detector o Selectable Current Limit for Reduced Ripple o Low-Noise, Anti-Ringing Feature (MAX1676) o 8-Pin and 10-Pin µMAX Packages o Preassembled Evaluation Kit (MAX1676EVKIT)
_______________Ordering Information
PART MAX1674EUA MAX1675EUA MAX1676EUB
TEMP. RANGE -40°C to +85°C -40°C to +85°C -40°C to +85°C
PIN-PACKAGE 8 µMAX 8 µMAX 10 µMAX
TOP VIEW
Pin Configurations
FB 1 LBI 2 LBO 3 REF 4
MAX1674 MAX1675
8 OUT 7 LX 6 GND 5 SHDN
µMAX
FB 1 LBI 2 LBO 3 CLSEL 4 REF 5
MAX1676 µMAX
10 OUT 9 LX 8 GND 7 BATT 6 SHDN
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
19-1360; Rev 3; 3/00
MAX1674/MAX1675/MAX1676
High-Efficiency, Low-Supply-Current, Compact, Step-Up DC-DC Converters
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (OUT to GND) ..............................-0.3V to +6.0V Switch Voltage (LX to GND) .....................-0.3V to (VOUT + 0.3V) Battery Voltage (BATT to GND).............................-0.3V to +6.0V SHDN, LBO to GND ..............................................-0.3V to +6.0V LBI, REF, FB, CLSEL to GND ...................-0.3V to (VOUT + 0.3V) Switch Current (LX) ...............................................-1.5A to +1.5A Output Current (OUT) ...........................................-1.5A to +1.5A
Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW 10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW
Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +165°C Lead Temperature (soldering, 10s) .................................+300°C
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
(VBATT = 2V, FB = OUT (VOUT = 3.3V), RL = ˙∞, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.)
PARAMETER Minimum Input Voltage Operating Voltage Start-Up Voltage Start-Up Voltage Tempco Output Voltage Output Voltage Range
Steady-State Output Current (Note 2)
Reference Voltage Reference Voltage Tempco Reference Voltage Load Regulation
SYMBOL
CONDITIONS
VIN TA = +25°C TA = +25°C, RL = 3kΩ (Note 1)
VOUT
FB = OUT FB = GND
IOUT
VREF TEMPCO
FB = OUT (VOUT = 3.3V)
MAX1674, MAX1676 (CLSEL = OUT)
MAX1675, MAX1676 (CLSEL = GND)
FB = GND (VOUT = 5V)
MAX1674, MAX1676 (CLSEL = OUT)
MAX1675, MAX1676 (CLSEL = GND)
IREF = 0
VREF_LOAD IREF = 0 to 100µA
MIN
1.1
3.17 4.80
2
TYP 0.7
0.9 -2 3.30 5
MAX
5.5 1.1
3.43 5.20 5.5
UNITS V V V
mV/°C
V
V
300 420
150 220 180 285
mA
90 1.274
130
1.30 0.024
3
1.326
V
mV/°C
15 mV
Reference Voltage Line Regulation
FB, LBI Input Threshold
Internal NFET, PFET On-Resistance
LX Switch Current Limit (NFET)
.