LM828M5 National Semiconductor, LM828M5 Datasheet - Page 8
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LM828M5
Manufacturer Part Number
LM828M5
Description
IC SW CAP/INV ADJ 25MA SOT23-5
Manufacturer
National Semiconductor
Type
Switched Capacitor (Charge Pump), Invertingr
Datasheet
1.LM828M5X.pdf
(12 pages)
Specifications of LM828M5
Internal Switch(s)
Yes
Synchronous Rectifier
No
Number Of Outputs
1
Voltage - Output
-1.8 ~ -5.5 V
Current - Output
25mA
Frequency - Switching
12kHz
Voltage - Input
1.8 ~ 5.5 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
SOT-23-5, SC-74A, SOT-25
Power - Output
240mW
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Other names
LM828M5TR
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COMBINED DOUBLER AND INVERTER
In Figure 5, the LM828 is used to provide a positive voltage
doubler and a negative voltage converter. Note that the total
current drawn from the two outputs should not exceed 40 mA.
REGULATING V
It is possible to regulate the negative output of the LM828 by
use of a low dropout regulator (such as the LP2980). The
whole converter is depicted in Figure 6. This converter can
give a regulated output from −1.8V to −5.5V by choosing the
proper resistor ratio:
OUT
V
out
where, V
= V
ref
ref
(1 + R
FIGURE 5. Increasing Output Voltage by Cascading Devices
= 1.23V
1
FIGURE 6. Combined Voltage Doubler and Inverter
/R
2
)
8
Note that the following conditions must be satisfied simulta-
neously for worst case design:
V
V
in_max
in_min
+ I
+ I
out_max
>V
< V
out_min
out_min
out_max
× R
× R
+V
out_max
out_min
+V
drop_max
drop_min
10013711
(LM828)
(LM828)
(LP2980)
10013710
(LP2980)