MAX669 MAXIM [Maxim Integrated Products], MAX669 Datasheet
MAX669
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MAX669 Summary of contents
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... BiCMOS design features low operating current (220µA), adjustable operating frequency (100kHz to 500kHz), soft-start, 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 Mode™ control scheme. The controller ...
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... Junction Temperature ......................................................+150°C LDO Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering,10sec) ..............................+300°C CONDITIONS MAX668 MAX669 Typically 0.013% per range 100mV for 0 to full CS load current. Typically 0.012% per % duty factor on EXT; EXT duty factor for a step-up is: 100% (1 – ...
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... CS+ forced to GND V = 1.30V 28V FB CC SYNC/SHDN = GND ≤ (includes LDO dropout) LDO load = ∞ to 400Ω 3V ≤ (includes LDO dropout) Sensed at LDO, falling edge, hysteresis = 1%, MAX669 only Controllers in µMAX = +25°C.) A MIN TYP 290 20 50 100 70 2 ...
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... R = 200kΩ ±1% OSC R = 100kΩ ±1% OSC R = 500kΩ ±1% OSC Not tested 3.0V < V < 28V CC 1.8V < V < 3.0V (MAX669) CC 3.0V < V < 28V CC 1.8V < V < 3.0V (MAX669) CC SYNC/SHDN = 5V SYNC/SHDN = 28V EXT high or low MIN MAX UNITS 1.22 1.28 V -10 mV 1.0 1.2 V 222 278 425 575 kHz ...
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... 2. BOOTSTRAPPED FIGURE 200k 100 1000 LOAD CURRENT (mA) MAX669 MINIMUM START-UP VOLTAGE vs. LOAD CURRENT 3 OUT 2.5 2 12V OUT 1.5 1.0 0.5 BOOTSTRAPPED FIGURE 100 200 300 400 500 600 700 800 900 1000 LOAD CURRENT (mA) SHUTDOWN CURRENT vs ...
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Input, PWM Step-Up Controllers in µMAX (Circuits of Figures and +25°C; unless otherwise noted.) A REFERENCE VOLTAGE vs. TEMPERATURE 1.250 1.249 1.248 1.247 1.246 1.245 1.244 1.243 1.242 1.241 V = ...
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Figures and +25°C; unless otherwise noted.) A EXITING SHUTDOWN OUTPUT VOLTAGE 5V/div INDUCTOR CURRENT 2A/div SHUTDOWN VOLTAGE 5V/div 500 s/div MAX668 5V 12V, LOAD = 1.0A ...
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... EXT with an open-loop, 50% duty-cycle start-up oscilla- tor when LDO is below 2.5V. It switches to closed-loop operation only when LDO exceeds 2.5V non-boot- strapped connection is used with the MAX669 and if V (the input voltage) remains below 2.7V, the output CC voltage will soar above the regulation point ...
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... UVLO R2 276k R3 276k MAIN PWM COMPARATOR + SYNC/SHDN + Controllers in µMAX Low-Dropout Regulator (LDO) , while its output is at LDO. All MAX668/MAX669 -to-LDO dropout voltage is typically CC - 200mV. When LDO is CC LDO EXT 0 MUX 1 PGND MAX668 MAX669 REF 1.25V BIAS OSC ...
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... PGND GND 220pF age range extends below 2.7V, then bootstrapped operation with the MAX669 is the only option. With V connected age swing is 5V when V 0.2V when V is less than 5.2V. If the output voltage CC does not exceed 5.5V, the on-chip regulator can be disabled by connecting V eliminates the LDO forward drop and supplies maxi- mum gate drive to the external FET ...
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12V IN 1 LDO 0.1 F SYNC/ 10 SHDN 4 REF C3 2 FREQ 0. 100k 1% Figure 4. MAX668 High-Voltage Non-Bootstrapped Configuration V = 2.7V to ...
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... In addition to the configurations shown in Table 2, the following guidelines may help when selecting a config- uration ever below 2.7V strapped to V and the MAX669 must be used. If OUT V never exceeds 5.5V, LDO may be shorted to OUT V and V to eliminate the dropout voltage of CC OUT the LDO regulator ...
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... The MAX669’s soft-start sequence does not start until LDO reaches 2.5V. Design Procedure The MAX668/MAX669 can operate in a number of DC- DC converter configurations including step-up, SEPIC (single-ended primary inductance converter), and fly- back. The following design discussions are limited to step-up, although SEPIC and flyback examples are shown in the Application Circuits section ...
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... Power MOSFET Selection The MAX668/MAX669 drive a wide variety of N-channel power MOSFETs (NFETs). Since LDO limits the EXT output gate drive to no more than 5V, a logic-level NFET is required. Best performance, especially at low input voltages (below 5V), is achieved with low-thresh- ...
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... The trace between the external gain-setting resistors and the FB pin must be extremely short, as must the trace between GND and PGND. to GND with CC Figure 3 shows the MAX669 operating in a low-voltage boost application. The MAX669 is configured in the ESR affects loop OUT bootstrapped mode to improve low input voltage per- formance ...
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Input, PWM Step-Up Controllers in µMAX larger or smaller than the output voltage, such as when converting four NiMH, NiCd, or Alkaline cells output. The SEPIC configuration is often a good choice for combined ...
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V = +5V IN 220 10V 0.22 F T1: COILTRONICS CTX03-14232 Figure 7. Isolated +5V to +5V at 400mA Power Supply Chip Information TRANSISTOR COUNT: 1861 ______________________________________________________________________________________ 1.8V to 28V Input, PWM Step-Up T1 2:1 LDO V ...
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Input, PWM Step-Up Controllers in µMAX 18 ______________________________________________________________________________________ Package Information ...