L5973AD STMicroelectronics, L5973AD Datasheet - Page 13

• Manufacturer Part Number: L5973AD
• Description: IC REG SW 2A STEPDOWN 8-SOIC
• Manufacturer: STMicroelectronics
• Type: Step-Down (Buck)r

Specifications of L5973AD

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 1.24 ~ 35 V
• Current - Output: 2A
• Frequency - Switching: 500kHz
• Voltage - Input: 4 ~ 36 V
• Operating Temperature: -40°C ~ 150°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width) Exposed Pad, 8-eSOIC. 8-HSOIC
• Power - Output: 2.25W
• Output Voltage: 35 V
• Output Current: 2 A
• Input Voltage: 4 V to 36 V
• Switching Frequency: 500 KHz
• Operating Temperature Range: - 40 C to + 150 C
• Mounting Style: SMD/SMT
• Duty Cycle (max): 100 %
• Low Dropout Operation: 100 % duty cycle
• For Use With: 497-4134 - EVAL BOARD FOR L5973 SERIES497-4133 - EVAL BOARD FOR L5973 SERIES
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-1417-5; 497-1417-5; 497-4565-5; E-L5973AD

L5973AD
5
5.1
5.2
5.3
5.4
Additional features and protections
Feedback disconnection
In case of feedback disconnection, the duty cycle increases versus the maximum allowed
value, bringing the output voltage close to the input supply. This condition could destroy the
load.
To avoid this dangerous condition, the device is turned off if the feedback pin remains
floating.
Output overvoltage protection
The overvoltage protection, OVP, is realized by using an internal comparator, which input is
connected to the feedback, that turns off the power stage when the OVP threshold is
reached. This threshold is typically 30% higher than the feedback voltage.
When a voltage divider is requested for adjusting the output voltage (see test application
circuit), the OVP intervention will be set at:
Equation 1
Where R
R
Zero load
Due to the fact that the internal power is a PDMOS, no boostrap capacitor is required and
so, the device works properly also with no load at the output. In this condition it works in
burst mode, with random repetition rate of the burst.
Application circuit
In
V
output voltage is adjustable from 1.235 V to V
CC
2
Figure 8
is between the feedback pin and ground.
, can range from 4 V to 25 V due to the rated voltage of the input capacitor and the
1
is the resistor connected between the output voltage and the feedback pin, while
is shown the demo board application circuit, where the input supply voltage,
V
Doc ID 9552 Rev 9
OVP
=
1.3
⋅
CC
R
------------------- - V
1
.
R
+
2
R
Additional features and protections
2
⋅
FB
13/22