LT1304-5.0V UTC, LT1304-5.0V Datasheet - Page 12

• Manufacturer Part Number: LT1304-5.0V
• Description: MICROPOWER DC/DC CONVERTERS
• Manufacturer: UTC

UTC LT1304/LT1304-3.3V/LT1304-5.0V
Why? As more current is drawn from the battery, voltage drop across the cells’ internal impedance increases. This
causes internal power loss (heating), reducing cell terminal voltage. Since the regulator input acts as a negative
resistance, more current is drawn from the battery as the terminal voltage decreases. This positive feedback action
compounds the problem.
efficiency approximates the electrical efficiency at load current levels from 1mA to 10mA, but drops severely at
load currents above 10mA (load power above 50mW). The moral of the story is this: if your system needs 5V at
more than 40mA to 50mA, consider using a NiCd battery (1/10 the internal impedance) instead of a AA cell alkaline
battery.
UTC
Figure 11’s graph varies significantly from electrical efficiency plot pictured on the first page of this data sheet.
Figure 12 shows overall energy conversion efficiency, assuming availability of 6.5WH of battery energy. This
UNISONIC TECHNOLOGIES CO., LTD.
Figure 11. Output Wall Hours vs Load Current.
Note Rapid Fall-Off at Higher Discharge Rates
LINEAR INTEGRATED CIRCUIT
6
4
3
5
2
1
0
1
LOAD CURRENT(mA)
10
100
200
QW-R103-018,A
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