RHFL4913
ADJUSTABLE
RAD-HARD ADJUSTABLE POSITIVE
VOLTAGE REGULATOR
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1-3 AMPERE LOW DROPOUT VOLTAGE
OPTIONAL OVERTEMPERATURE,
OVERCURRENT PROTECTIONS
ADJUSTABLE OVERCURRENT LIMITATION
LOAD SHORT CIRCUIT MONITORING
ADJUSTABLE OUTPUT VOLTAGE
INHIBIT (ON/OFF) TTL COMPATIBLE
CONTROL
PROGRAMMABLE OUTPUT SHORT
CIRCUIT CURRENT
REMOTE SENSING OPERATION
RADHARD: SUSTAINS 300krad IN MIL
1019.5 AND LOW DOSE RATE CONDITIONS
HEAVY IONS SEL, SEU IMMUNE.
SUSTAINS 2x10
14
proton/cm
2
, AND 5x10
14
neutron/cm
2
FPC-16
FPC-14
SOC-14
DESCRIPTION
The RHFL4913 ADJUSTABLE is a high
performance Rad Hard Adjustable Positive
Voltage Regulator.
Available into various hermetic ceramic packages,
it is specifically intended for Space and harsh
radiation environments. Input supply range is from
3 to 12 volts.
The RHFL4913 ADJUSTABLE is Qml-V Qualified,
DSCC Smd is 596202524.
BLOCK DIAGRAM
January 2004
1/10
RHFL4913 ADJUSTABLE VERSION
DEVICE DESCRIPTION
The RHFL4913 Adjustable contains a PNP type power element controlled by a signal resulting from
amplified comparison between the internal temperature compensated Band-Gap and the fraction of the
desired Output Voltage value obtained from an external resistor divider bridge. The device is protected by
several functional blocks.
ADJ pin
The Load output voltage feed-back comes from an external divider resistor bridge middle point connected
to ADJ pin (allowing all possible output voltage settings as per User’s desire) established between Load
terminals.
INHIBIT ON-OFF Control
By setting INHIBIT pin TTL-High, the Device switches off the Output Current and Voltage. Device is ON
when INHIBIT pin is set Low. Since INHIBIT pin is internally pulled down, it can be left floating in case
Inhibit function is not utilized.
Overtemperature protection
A temperature detector internally monitors the power element junction temperature. The Device goes
OFF when approx. 175°C are reached, returning to ON mode when back to approx. 40°C. Combined with
other protection blocks, it protects the Device from destructive junction temperature excursions in all load
conditions. It is worth noting that when internal temperature detector reaches 175°C, the active power
element can be at 225°C: Extensive operation under these conditions far exceeds Maximum Operation
Ratings and Device reliability cannot be granted.
Overcurrent protection
An internal non-fold back Short-Circuit limitation is set with I
SHORT
> 3.8A (V
O
is 0V). This value can be
downwards modified by an external resistor connected between I
SC
pin and V
I
pin, with a typical value
range of 10kΩ to 200kΩ. To keep excellent V
O
regulation, it is necessary to set I
SHORT
1.6 times greater
than the maximum desired application I
O
. When I
O
reaches I
SHORT
– 300mA, the current limiter overrules
Regulation and V
O
starts to drop and OCM flag is risen. When no current limit adjustment is required, I
SC
pin must be left unbiased (as it is in 3pin packages).
OCM pin
Goes Low when current limit starts to be active, otherwise V
OCM
= V
I
. It is buffered and can sink 10mA.
OCM pin is internally pulled-up by a 50 kΩ resistor.
Alternates to: RHFL4913 is recommended to replace all Industry Positive Regulators due to its
exceptional Radiation performance. To replace 3-terminal Industry devices, use RHFL4913 Fixed
Voltage versions.
APPLICATION INFORMATION
Adjusting Output Voltage: R2 resistor must be connected between V
O
and ADJ. R1 resistor must be
connected between ADJ and Ground. Resistor values can be derived from the following formula:
V
O
= V
ADJ
x R1 / (R1+ R2)
V
ADJ
is 1.22V, controlled by the internal temperature compensated Band Gap block.
The minimum Output voltage is therefore 1.22V and minimum Input voltage is 3V.
The RHFL4913 Adjustable is functional as soon as V
I
- V
O
voltage difference is slightly above the power
element saturation voltage. The Adjust pin to Ground resistor must not be bigger than 10kΩ to keep the
output feed-back error below 0.2%. A minimum 0.5mA I
O
must be set to ensure perfect “no-load”
regulation. It is advisable to dissipate this current into the divider bridge resistor. All available V
I
pins shall
always be externally interconnected, same thing for all available V
O
pins, otherwise Device stability and
reliability cannot be granted. The INHIBIT function switches off the output current in an electronic way,
that is very quickly. According to Lenz’s Law, external circuitry reacts with LdI/dt terms which can be of
high amplitude in case somewhere an inductance exists. Large transient voltage would develop on both
Device terminals. It is advisable to protect the Device with Schottky diodes preventing negative voltage
excursions. In the worst case, a 14V Zener diode shall protect the Device Input. The Device has been
5/10
Creative Market
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