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Part: MAX669
Category:
Power Management
-> Regulators
-> Switching Regulators
Description: 1.8V to 28V Input PWM Step-up Controllers in Max
Company: Maxim Integrated Products
Datasheet: Download MAX669 datasheet File size : 373 kB
Request For quote: Find where to buy MAX669
Datasheet text preview:
19-4778; Rev 1; 1/02
K ATION EVALU BLE AVAILA
IT
1.8V to 28V Input, PWM Step-Up Controllers in µMAX
General Description Features
o 1.8V Minimum Start-Up Voltage (MAX669) o Wide Input Voltage Range (1.8V to 28V) o Tiny 10-Pin µMAX Package o Current-Mode PWM and Idle ModeTM Operation o Efficiency Over 90% o Adjustable 100kHz to 500kHz Oscillator or SYNC Input o 220µA Quiescent Current o Logic-Level Shutdown o Soft-Start
MAX668/MAX669
The MAX668/MAX669 constant-frequency, pulse-width modulating (PWM), current-mode DC-DC controllers are designed for a wide range of DC-DC conversion applications including step-up, SEPIC, flyback, and isolatedoutput configurations. Power levels of 20W or more can be controlled with conversion efficiencies of over 90%. The 1.8V to 28V input voltage range supports a wide range of battery and AC-powered inputs. An advanced BiCMOS design features low operating current (220µA), adjustable operating frequency (100kHz to 500kHz), s o f t - s t a r t , and a SYNC input allowing the MAX668/ MAX669 oscillator to be locked to an external clock. DC-DC conversion efficiency is optimized with a low 100mV current-sense voltage as well as with Maxim's proprietary Idle ModeTM control scheme. The controller operates in PWM mode at medium and heavy loads for lowest noise and optimum efficiency, then pulses only as needed (with reduced inductor current) to reduce operating current and maximize efficiency under light loads. A logic-level shutdown input is also included, reducing supply current to 3.5µA. The MAX669, optimized for low input voltages with a g u a r a n t e e d start-up voltage of 1.8V, requires bootstrapped operation (IC powered from boosted output). It supports output voltages up to 28V. The MAX668 operates with inputs as low as 3V and can be connected in either a bootstrapped or non-bootstrapped (IC powered from input supply or other source) configuration. When not bootstrapped, it has no restriction on output voltage. Both ICs are available in an extremely compact 10-pin µMAX package.
Applications
Cellular Telephones Telecom Hardware LANs and Network Systems POS Systems
Ordering Information
PART MAX668EUB MAX669EUB TEMP RANGE -40°C to +85°C -40°C to +85°C PIN-PACKAGE 10 µMAX 10 µMAX
Idle Mode is a trademark of Maxim Integrated Products.
Typical Operating Circuit
VIN = 1.8V to 28V
Pin Configuration
TOP VIEW
VOUT = 28V SYNC/ SHDN FREQ VCC EXT CS+ LDO 1 FREQ GND 2 3 4 5 10 SYNC/SHDN 9 VCC EXT PGND CS+
MAX668 MAX669
8 7 6
MAX669
LDO PGND FB REF GND
REF FB
µMAX
________________________________________________________________ Maxim Integrated Products
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For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
1.8V to 28V Input, PWM Step-Up Controllers in µMAX MAX668/MAX669
ABSOLUTE MAXIMUM RATINGS
VCC to GND ..........-0.3V to +30V PGND to GND...........±0.3V SYNC/SHDN to GND ............-0.3V to +30V EXT, REF to GND....-0.3V to (VLDO + 0.3V) LDO, FREQ, FB, CS+ to GND ........ -0.3V to +6V LDO Output Current..........-1mA to +20mA REF Output Current....-1mA to +1mA LDO Short Circuit to GND ........Momentary REF Short Circuit to GND .........Continuous Continuous Power Dissipation (TA = +70°C) 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 +150°C Lead Temperature (soldering,10sec) ......+300°C
ELECTRICAL CHARACTERISTICS
(VCC = LDO = 5V, ROSC = 200k, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER PWM Controller PWM CONTROLLER Input Voltage Range, VCC Input Voltage Range with VCC Tied to LDO FB Threshold FB Threshold Load Regulation Typically 0.013% per mV on CS+; VCS+ range is 0 to 100mV for 0 to full load current. Typically 0.012% per % duty factor on EXT; EXT duty factor for a step-up is: 100% (1 VIN/VOUT) VFB = 1.30V 85 5 CS+ forced to GND VFB = 1.30V, VCC = 3V to 28V SYNC/SHDN = GND, VCC = 28V 5V VCC 28V (includes LDO dropout) 3V VCC 28V (includes LDO dropout) MAX668 MAX669 3 1.8 2.7 1.225 1.250 0.013 28 28.0 5.5 1.275 V V V %/mV CONDITIONS MIN TYP MAX UNITS
FB Threshold Line Regulation FB Input Current Current-Limit Threshold Idle Mode Current-Sense Threshold CS+ Input Current VCC Supply Current (Note 1) Shutdown Supply Current (VCC) REferenceCE AND LDO REGULATORS eFEREN and LDO Regulators
0.012 1 100 15 0.2 220 3.5 20 115 25 1 350 6
%/% nA mV mV µA µA µA
4.50 2.65 2.40 1.225 1.0 225 425 85
5.00
5.50 V 5.50
LDO Output Voltage
LDO load = to 400
Undervoltage Lockout Threshold REF Output Voltage REF Load Regulation REF Undervoltage Lockout Threshold OSCILLATOR Oscillator
Sensed at LDO, falling edge, hysteresis = 1%, MAX668 only No load, CREF = 0.22µF REF load = 0 to 50µA Rising edge, 1% hysteresis ROSC = 200k ±1%
2.50 1.250 -2 1.1 250 500 100
2.60 1.275 -10 1.2 275 575 115
V V mV V
Oscillator Frequency
ROSC = 100k ±1% ROSC = 500k ±1%
kHz
2
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1.8V to 28V Input, PWM Step-Up Controllers in µMAX
ELECTRICAL CHARACTERISTICS (continued)
(VCC = LDO = 5V, ROSC = 200k, TA = 0°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) PARAMETER Maximum Duty Cycle Minimum EXT Pulse Width Minimum SYNC Input-Pulse Duty Cycle Minimum SYNC Input Low Pulse Width SYNC Input Rise/Fall Time SYNC Input Frequency Range SYNC/SHDN Falling Edge to Shutdown Delay SYNC/SHDN Input High Voltage SYNC/SHDN Input Low Voltage SYNC/SHDN Input Current EXT Sink/Source Current EXT On-Resistance 3V < VCC < 28V 1.8V < VCC < 3V (MAX669) 3V < VCC < 28V 1.8V < VCC < 3V (MAX669) SYNC/SHDN = 5V SYNC/SHDN = 28V EXT forced to 2V EXT high or low 0.5 1.5 1 2 5 2.0 1.5 0.45 0.30 3.0 6.5 Not tested 100 70 CONDITIONS ROSC = 200k ±1% ROSC = 100k ±1% ROSC = 500k ±1% MIN 87 86 86 TYP 90 90 90 290 20 50 45 200 200 500 MAX 93 94 94 ns % ns ns kHz µs V V µA A % UNITS
MAX668/MAX669
ELECTRICAL CHARACTERISTICS
(VCC = LDO = 5V, ROSC = 200k, TA = -40°C to +85°C, unless otherwise noted.) (Note 2) PARAMETER PWM Controller PWM CONTROLLER Input Voltage Range, VCC Input Voltage Range with VCC Tied to LDO FB Threshold FB Input Current Current-Limit Threshold Idle Mode Current-Sense Threshold CS+ Input Current VCC Supply Current (Note 1) Shutdown Supply Current (VCC) RefFEencNCE AND LDO REGULATORS E er RE e and LDO Regulators LDO load = to 400 5V VCC 28V (includes LDO dropout) 3V VCC 28V (includes LDO dropout) 4.50 2.65 2.40 5.50 V 5.50 2.60 V V CS+ forced to GND VFB = 1.30V, VCC = 3V to 28V SYNC/SHDN = GND, VCC = 28V VFB = 1.30V 85 3 MAX668 MAX669 3 1.8 2.7 1.22 28 28 5.5 1.28 20 115 27 1 350 6 V V V nA mV mV µA µA µA CONDITIONS MIN MAX UNITS
LDO Output Voltage
LDO Undervoltage Lockout Threshold
Sensed at LDO, falling edge, hysteresis = 1%, MAX669 only
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