Low_dropout_linear_regulator

Published:2009/7/25 4:21:00 Author:Jessie | From:SeekIC

Figure 8－126 shows a MAX666 linear regulator connected to provide a 5-V output. This circuit is useful for uninterruptible battery-backup applications, as well as forlow-power circuits that use batteries for maln power and optionally take powerfrom wall-cube ac adapters．The input-voltage range is 5.4 V to 16.5 V, quiescent current(VIN ＝10 V) is 20 μA, dropout voltage (with 100－mA load) is 400 mV，maximum load current (VIN＝6 V) is 500 mA and shutdown current is 5 μA，Figure 8-127 shows the efficiency curves．Notice that the pass transistor is externaland can be sized to handle the required power dissipation．If the dissipation is lowenough the MAX666 internal 50-mA power transistor can replace the 2N2905．TheMAX667 should also be considered In such cases. (The MAX667 has a larger, 250－mA pass transistor and lower dropout voltage.) MAXIM BATTERY MANAGEMENT CIRCUIT COLLECTION, 1994, P. 74．



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