MAX797H Maxim, MAX797H Datasheet
MAX797H
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MAX797H Summary of contents
Page 1
... The SKIP override input allows automatic switchover to idle-mode operation (for high-efficiency pulse skipping) at light loads, or forces fixed-frequency mode for lowest noise at all loads. The MAX797H is pin compatible with the popu- lar MAX797, but has a higher input voltage range. The MAX797H comes in a 16-pin narrow SO package. ...
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... REF Short Circuit to GND ...........................................Continuous VL Output Current ...............................................................50mA Continuous Power Dissipation (T SO (derate 8.70mW/°C above +70°C) ........................696mW Operating Temperature Range MAX797HESE .................................................-40°C to +85°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°C = 0°C to +85°C, SYNC = 0V, unless otherwise noted.) A CONDITIONS < ...
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... Oscillator Frequency SYNC = SYNC High Pulse Width SYNC Low Pulse Width SYNC Rise/Fall Time Guaranteed by design Oscillator Sync Range SYNC = REF Maximum Duty Factor SYNC = SYNC Input High Voltage SHDN, SKIP SYNC Input Low Voltage SHDN, SKIP SHDN 30V ...
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... Oscillator Frequency SYNC = SYNC High Pulse Width SYNC Low Pulse Width Oscillator Sync Range SYNC = REF Maximum Duty Factor SYNC = On-Resistance High or low DH On-Resistance High or low, BST - LX = 4.5V Note 1: Since the reference uses VL as its supply, V+ line-regulation error is insignificant. ...
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... High-Side Gate-Drive Output. DH normally drives the main buck switch floating driver output that 16 DH swings from LX to BST, riding on the LX switching-node voltage. Dual Mode is a trademark of Maxim Integrated Products. Rail-to-Rail is a registered trademark of Nippon Motorola Ltd. _______________________________________________________________________________________ FUNCTION and V specifications) ...
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... The only difference between the two devices is in the BST pin’s absolute maximum rating. The MAX797H’s rating is 46V; the MAX797’s rating is 36V. The higher rating allows the MAX797H to use a power input up to 40V, provided that the V+ pin is powered by a separate supply between 4.5V and 30V. ...
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... This means that duty factor is not an issue except at the maximum input voltage and minimum output voltage. For example the lowest V that does not require less than the OUT _______________________________________________________________________________________ +5V REGULATED SUPPLY V+ VL SHDN MAX797H DH BST SS LX REF DL PGND SYNC CSH GND CSL SKIP FB minimum duty factor is 40V x 0 ...
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... Figure 3. Dividing the Power Input to Supply +40V POWER INPUT R1 Figure 5. Powering V+ with a Zener Dropping Diode ___________________Chip Information TRANSISTOR COUNT: 913 Printed USA is a registered trademark of Maxim Integrated Products. +8V TO +40V POWER INPUT 100k Q1 300k V+ VL MAX797H DH +20V TO +40V POWER INPUT 12V V+ VL SHDN MAX797H DH ...