l7913adie2v STMicroelectronics, l7913adie2v Datasheet - Page 8

• Manufacturer Part Number: l7913adie2v
• Description: Rad-hard Adjustable Negative Voltage Regulator
• Manufacturer: STMicroelectronics

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Device description
The RHFL7913 adjustable contains a NPN-type power element controlled by signal
resulting from amplified comparison between internal temperature compensated band-gap
cell and the fraction of the desired output voltage value, generated by an external resistor
divider bridge. The NPN structure allows access to lower drop out levels because its base
current can be routed to ground pin and not to output. To control and monitor the device
from / to the external logic world – usually operating in positive voltage area – a dedicated
logic interface block (INHIBIT and OCM functions) has been implemented with +3 V to +5 V
supplied line (V+). In case V(+) = 0 V, inhibit and OCM functions are not available: In this
condition, INHIBIT function is ON and OCM pin is “no care”. The device is internally
protected by several blocks.
ADJ pin
The load voltage feed back comes from an external divider resistor bridge middle point to
ADJ pin established between load terminals.
Inhibit ON-OFF control
When INHIBIT pin is TTL-high (positive), the device switches off current and voltage output.
The device is ON when INHIBIT pin is set TTL-low.
Overtemperature protection
A temperature detector internally monitors power element junction temperature. The device
goes OFF circa 165 °-175 °C are reached, and returns ON when circa 100 °C. When
internal temperature detector reaches 170 °C, the active power element can be at 225 °C:
Device reliability cannot be granted during extensive operation duration with these
conditions.
Overcurrent protection
I
This value can be downward modified by an external resistor connected between I
pins, with a typical value range of 10 kΩ to 200 kΩ . To keep excellent V
necessary to set I
I
and OCM flag is risen. When no current limitation adjustment is required, I
unbiased (as it is in 3 pin packages).
OCM pin
Goes low when current limitor starts to be active, otherwise V
and can sink 10 mA. OCM pin is internally pulled-up by a 50 kΩ resistor. Can left open when
V (+) = 0.
SC
O
reaches I
pin. An internal non-fold back short-circuit limitation is set with I
SHORT
SHORT
– 300 mA, the current limitor overrules regulation and V
1.6 times greater than the maximum desired application I
OCM
= V (+). It is bufferized
SHORT
O
regulation, it is
SC
> 4 A (V
O
pin shall be left
starts to drop
SC
O
O
. When
is 0 V).
and V
I