E-L5973AD STMicroelectronics, E-L5973AD Datasheet

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... A switch step down switching regulator Description The L5973AD is a step down monolithic power switching regulator with a switch current limit able to deliver more than 1 current to the load depending on the application conditions. The output voltage can be set from 1.235 The high current level is also achieved ...

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... Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 Pin connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2 Electrical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4 Functional description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1 Power supply and voltage reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2 Voltages monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.3 Oscillator and synchronization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.4 Current protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.5 Error amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 4 ...

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... A logical signal (active high) disables the device. With IHN higher than 2.2 V the device is OFF and with INH lower than 0.8V, the device is ON. If INH is not used the pin must be grounded. When it is open, an internal pull- up disables the device. E/A output to be used for frequency compensation. ...

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... Electrical data 2 Electrical data 2.1 Maximum ratings Table 2. Absolute maximum ratings Symbol V Input voltage 8 V Output DC voltage 1 Output peak voltage 0.1 μs I Maximum output current Analog pins INH 3 V SYNC 2 P Power dissipation at T TOT T Operating junction temperature range J T Storage temperature range STG 2 ...

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... L5973AD 3 Electrical characteristics ° unless otherwise specified J CC Table 4. Electrical characteristics Symbol Operating input voltage V CC range MOSFET on R DS(on) resistance Maximum limiting I l current f Switching frequency s Duty cycle Dynamic characteristics (see test circuit). V Voltage feedback 5 η Efficiency DC characteristics Total operating ...

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... V = 1.9 V COMP 0.74 V sync V = 2.33 V sync source no load, V sync REF REF REF Doc ID 9552 Rev 9 Min Typ Max 2.3 2.5 V REF 0.74 (1) 0.11 0.25 0.21 0.45 2. 1.65 V 0.20 0.35 3.234 3.3 3.366 3.2 3.3 3.399 L5973AD Unit mS V ...

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... 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. ...

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... The clock generator provides the switching frequency of the device that is internally fixed at 500 kHz. The frequency shifter block acts reducing the switching frequency in case of strong overcurrent or short circuit. The clock signal is then used in the internal logic circuitry and is the input of the ramp generator and synchronization blocks. ...

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... In particular, connecting together two devices, the one with the lower switching frequency works as Slave and the other one works as Master. To synchronize the device, the SYNC pin has to pass from a low level to a level higher than the synchronization threshold with a duty cycle that can vary approximately from 10% to 90%, depending also on the signal frequency and amplitude ...

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... The voltage error amplifier is the core of the loop regulation transconductance operational amplifier whose non inverting input is connected to the internal voltage reference (1.235 V), while the inverting input (FB) is connected to the external divider or directly to the output voltage. The output (COMP) is connected to the external compensation network ...

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... At a first approach, it looks like the faster it is the rise time, the lower are the turn on losses. But there is a limit introduced by the recovery time of the recirculation diode. In fact when the current of the power element equals the inductor current, the diode turns off and the drain of the power is free to go high ...

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... With INH pin lower than 0.8 V, the device is enabled. If the INH pin is left floating, an internal pull up ensures that the voltage at the pin reaches the inhibit threshold and the device is disabled. ...

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... Application circuit In Figure 8 is shown the demo board application circuit, where the input supply voltage can range from due to the rated voltage of the input capacitor and the CC output voltage is adjustable from 1.235 Additional features and protections ...

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... INH GND 22nF C3 R3 220pF 4.7K Part Number GRM32DR61E106KA12L POSCAP 6TPB330M C1206C221J5GAC C1206C223K5RAC 5.6 K, 1%, 0.1 W 0603 3.3 K, 1%, 0.1 W 0603 4.7 K, 1%, 0.1 W 0603 STPS2L25U DO3316P-153 Doc ID 9552 Rev 9 L1 15μH OUT STPS2L25U 5. 3.3K D03IN1454 Description Manufacturer 10 μ MURATA 330 μF, 6.3 V ...

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... Vin=12V Vin=12V Vo=3.3V Vo=3. Tam b=25°C Tam b=25° Vo=1.8V Vo=1. 0.2 0.2 1.4 1.4 1.6 1.6 1.8 1 Figure 12. Efficiency vs output current Vout=3.3V Vout=3. Vout=2.5V Vout=2. Vout=1.8V Vout=1. 0.2 0.2 1.2 1.2 1.4 1.4 1.6 1.6 1.8 1 Doc ID 9552 Rev 9 ...

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... Application ideas 6 Application ideas Figure 13. Positive buck-boost regulator Figure 14. Buck-boost regulator VIN = 10μF 10μF 10V 25V CERAMIC CERAMIC Figure 15. Dual output voltage with auxiliary winding VIN = 5V C1 10μF 25V CERAMIC 16/22 VREF 3.3V 6 VCC 8 L5973AD SYNC. 2 COMP INH 22nF C3 R3 220pF 4 ...

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... Related part numbers are: ● L5970D: 1 ● L5972D ● L5973D: 2 case higher current is needed, the nearest DC-DC Converter family is L497x. ), 250 kHz step down DC-DC Converter in SO8 sw ), 250 kHz step down DC-DC Converter in SO8 sw ), 250 kHz step down DC-DC Converter in HSOP8 sw ...

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... Package mechanical data 7 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: ECOPACK trademark. 18/22 Doc ID 9552 Rev 9 L5973AD www.st.com. ...

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... Doc ID 9552 Rev 9 Package mechanical data inch Min Typ Max 0.0669 0.00 0.0059 0.0492 0.0122 0.0201 0.0067 0.0098 0.1890 0.1929 0.1969 0.118 0.122 0.126 0.2283 ...

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... Order code 8 Order code Table 8. Ordering information Order code L5973AD L5973ADTR 20/22 Package HSOP8 (Exposed pad) HSOP8 (Exposed pad) Doc ID 9552 Rev 9 L5973AD Packaging Tube Tape and reel ...

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... Date December 2003 January 2004 December 2004 November 2005 14-Dec-2006 15-Jan-2007 11-Oct-2007 24-Oct-2007 01-Nov-2009 Revision 1 First Issue 2 Migration to EDOCS 3 Added D1 and E1 dimensions in HSOP8 package information. 4 Updated the package information section. V value updated been reformatted. Modified V value Table 6 on page Updated Table 6: Component List on page 14 ...

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