LTC3260_15 Datasheet, PDF (13/18 Pages) Linear Technology – Low Noise Dual Supply Inverting Charge Pump

Applications Information
6
θ_JA = 43°C/W
5
4
3
T_J = 150°C
2
1
RECOMMENDED
OPERATION
0
–50 –25 0 25 50 75 100 125 150 175
AMBIENT TEMPERATURE (°C)
3260 F06
Figure 6. Maximum Power Dissipation vs Ambient Temperature
LTC3260
The derating curve in Figure 6 assumes a maximum ther-
mal resistance, θ_JA, of 43°C/W for the package. This can
be achieved with a four layer PCB that includes 2oz Cu
traces and six vias from the exposed pad of the LTC3260
to the ground plane.
It is recommended that the LTC3260 be operated in the
region corresponding to T_J ≤ 150°C for continuous op-
eration as shown in Figure 6. Operation beyond 150°C
should be avoided as it may degrade part performance
and lifetime. At high temperatures, typically around 175°C,
the part is placed in thermal shutdown and all outputs are
disabled. When the part cools back down to a low enough
temperature, typically around 165°C, the outputs are re-
enabled and the part resumes normal operation.
Typical Applications
Low Power ±24V Power Supply from a Single-Ended 28V Input Supply
28V
9
V_IN
LDO^{+ 10}
C1
4.7µF ₁
LTC3260
EN⁺
ADJ⁺
13
11 _EN–
BYP^{+ 14}
12
MODE
15
GND
C2
1µF
8 _C+
7 _C–
BYP^{– 3}
ADJ^{– 4}
C3
4.7µF
6
V_OUT
LDO^{– 5}
RT
2
C4
4.7µF
24V
R1
1.91M
R2
100k
R3
100k
C7
4.7µF
R4
1.91M
–24V
3260 TA02
High Voltage Input to Bipolar Output with Highly Efficient Dividing/Inverting Charge Pump
13.5V TO 32V
C2
1µF
50V
C1
4.7µF
50V
D1
11
V_IN
1 _EN+
13 _EN–
10 _C+
LDO^{+ 12}
ADJ^{+ 15}
BYP^{+ 16}
MBR0540
LTC3260
D3
MBR0540
D2
MBR0540
C3
BYP^{– 3}
ADJ^{– 4}
1µF
50V
7 _C–
NOTE: THE LTC3260 WILL ALWAYS RUN
IN CONTINUOUS FREQUENCY REGARDLESS
LDO^{– 5}
V_OUT ⁶
OF THE MODE PIN SETTING BECAUSE V_OUT
IS ALWAYS LESS THAN –1/2V_IN
MODE GND RT
14 17 2
5V
R1
C4
316k
4.7µF
R2
C5
100k
0.01µF
C6
0.01µF
R3
100k
R4
316k
–5V
C7
C8
4.7µF
4.7µF
3260 TA04
25V
V_OUT

~ – _
V_IN
– V_F
– I_OUT
2
•ROL

– V_{F }
3260fa
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