L5973AD STMicroelectronics, L5973AD Datasheet - Page 7

• 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
4
Functional description
The main internal blocks are shown in
They are:
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Figure 3.
A voltage regulator that supplies the internal circuitry. From this regulator, a 3.3 V
reference voltage is externally available.
A voltage monitor circuit that checks the input and internal voltages.
A fully integrated sawtooth oscillator whose frequency is 500 kHz
Two embedded current limitations circuitries which control the current that flows
through the power switch. The Pulse by Pulse Current Limit forces the power switch
OFF cycle by cycle if the current reaches an internal threshold, while the Frequency
Shifter reduces the switching frequency in order to strongly reduce the duty cycle.
A transconductance error amplifier.
A pulse width modulator (PWM) comparator and the relative logic circuitry necessary to
drive the internal power.
An high side driver for the internal P-MOS switch.
An inhibit block for stand-by operation.
A circuit to realize the thermal protection function.
Block diagram
Doc ID 9552 Rev 9
Figure
3, where is reported the device block diagram.
Functional description
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