Datasheet

Select preset voltage mode by connecting SET to ground.
In adjustable mode, select an output between +2.5V and
+11V using two external resistors connected as a voltage-
divider to SET (Figure 4). Set the output voltage using the
following equation:
V
OUT
= V
SET
(1 + R1 / R2)
where V
SET
= 1.248V and R2 ≈ 100kΩ.
Available Output Current Calculation
The MAX5023/MAX5024 high-voltage regulator provides
up to 150mA of output current. The input voltage extends
to +65V. Package power dissipation limits the amount of
output current available for a given input/output voltage
and ambient temperature. Figure 5 depicts the maximum
power dissipation curve for these devices. The graph
assumes that the exposed metal pad of the MAX5023/
MAX5024 package is soldered to 1in
2
of PC board copper.
Use Figure 5 to determine the allowable package dissi-
pation for a given ambient temperature. Alternately, use
the following formula to calculate the allowable package
dissipation:
( )
A
D
AA
1.538W for T 70 C
P
1.538 - 0.01923 T - 70 C for 70 C T 125 C
≤+ °


=

° + ° < ≤+ °


After determining the allowable package dissipation,
calculate the maximum output current using the following
formula:
( )
D
OUT MAX
IN OUT
P
I 150mA
V -V
≅≤
The above equations do not include the negligible power
dissipation from self-heating due to the IC ground current.
Table 1. Truth Table for Regulator Output
State
Figure 4. Setting the MAX5024 Adjustable Output Voltage
X = Don’t care.
Figure 5. Maximum Power Dissipation vs. Temperature
ORDER EN
HOLD
OUT Comments
1 Low X Off
Initial state. EN has 5MΩ
internal resistor to ground.
HOLD has internal current
source to OUT.
2 High X On
Regulator output is active
when EN is pulled high.
3 High Low On
Hold is asserted forcing the
regulator output on even if
EN goes low.
4 X Low On
Self-holding state. Regulator
output stays on regardless of
the state of EN.
5 Low High Off
Regulator output is shutdown
by releasing HOLD while EN
remains low.
10 20 30 40 50 60 70 80 90 100 110 120 130 140 150
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
T
A
(°C)
P
D
(W)
DERATE
19.23mW/°C
1.538W
IN
EN
GND
HOLD
V
OUT
= V
SET
(1 + R1 / R2)
V
SET
= 1.248V
R2 = 1kΩ TO 500kΩ
SET
OUT
RESET
TO µP
15µF
R1
+6.5V TO +65V
+2.5V TO +11V
ON
OFF
R2
MAX5024
10µF
MAX5023/MAX5024 65V, Low-Quiescent-Current, High-Voltage Linear
Regulators with μP Reset and Watchdog Timer
www.maximintegrated.com
Maxim Integrated │ 11