MAX15006_11 Datasheet, PDF (10/14 Pages) Maxim Integrated Products – 40V, Ultra-Low Quiescent-Current Linear Regulators in 6-Pin TDFN/8-Pin SO

40V, Ultra-Low Quiescent-Current
Linear Regulators in 6-Pin TDFN/8-Pin SO
Applications Information
Output Voltage Setting
The MAX15006C/MAX15007C provide an adjustable
output voltage from 1.8V to 10V and do not operate in a
preset output voltage mode. Connect an external resis-
tive divider from OUT to FB to GND as shown in Figure
4 to set the desired output voltage. V_OUT is calculated
as follows:
V_OUT
=
V_FB
×
⎛
⎝⎜
1
+
R1 ⎞
R2 ⎠⎟
where V_FB = 1.23V and a 5μA minimum current is
required in the external divider for stability.
Available Output Current Calculation
The MAX15006/MAX15007 provide up to 50mA of contin-
uous output current. The input voltage range extends to
40V. Package power dissipation limits the amount of out-
put current available for a given input/output voltage and
ambient temperature. Figure 5 shows the maximum
allowable power dissipation for these devices to keep the
junction temperature below +150°C. Figure 5 assumes
that the exposed metal pad of the MAX15006/MAX15007
is soldered to 1in² of PCB copper.
Use Figure 5 to determine the allowable package dissi-
pation for a given ambient temperature. Alternately, use
the following formulas to calculate the allowable pack-
age dissipation. For the TDFN package:
P_D
=
⎧⎪1.9048W
⎨⎩⎪_1.9048W
for T_A ≤ + 70°C
−
0.0238
W
°C
x
( TA
–
70°C)
for
+
70°C
<
T_A
≤
+
⎫⎪
125°C
⎬
⎭⎪
For the SO-EP package:
P_D
=
⎧⎪1.8605W
⎨⎩⎪_1.8605W
for T_A ≤ + 70°C
− 0.0233 ^W x (
°C
T_A
–
70°C)
for
+
70°C
<
T_A
≤
+
125°C
⎫⎪
⎬
⎭⎪
After determining the allowable package dissipation,
calculate the maximum allowable output current, with-
out exceeding the +150°C junction temperature, using
the following formula:
I_OUT(MAX)
=
V_IN
P_D
− V_OUT
≤ 50mA
The above equations do not include the negligible
power dissipation from self-heating due to the IC
ground current.
Example 1 (TDFN Package):
T_A = +125°C
V_IN = 26V
V_OUT = 3.3V
Calculate the maximum allowable package dissipation
at the given temperature as follows:
P_D = 1.9048W
− 0.0238 ^W (125°C
°C
− 70°C) =
595.8mW
And establish the maximum output current:
I_OUT(MAX)
=
595.8mW
26V − 3.3V
=
26.2mA
+4V TO +40V
0.1μF
ON
OFF
IN
OUT
MAX15007C
FB
EN
GND
+1.8V TO +10V
2.2μF
R1
R2
VOUT = VFB (1 + R1/R2)
VFB = 1.23V
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
1.9408W
(6-PIN TDFN)
1.8605W
(8-PIN SO-EP)
DERATE
23.8mW/°C
DERATE
23.3mW/°C
20 40 60 80 100 120 140
TEMPERATURE (°C)
Figure 4. Setting the Adjustable Output Voltage
Figure 5. Calculated Maximum Power Dissipation vs. Ambient
Temperature
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