good LDO with reverse blocking, good enter vary, and extra


Reverse blocking is beneficial if a load must be equipped from an enter with quick interruptions in provide – most LDOs will conduct massive currents in reverse if they’re fed from a low-impedance provide that drops out, with subsequent danger of harm, to not point out draining the output capacitor risking an output brown-out even when the regulator will not be broken.

Including a diode in collection with the enter of a traditional might help – however the entire thing is not an LDO because it has a diode drop added to its nominal drop-out voltage. Some non-LDO regulators naturally have reverse-blocking by means of having npn move parts.

TI TPS7B7701-Q1 LDO reverse blocking wide input app EinW

Anyway, again to the TPS7B7701-Q1.


It’s an automotive (AEC-Q100 certified) regulator supposed to feed energy as much as antennas with little between it and the car’s 12V battery.

As such, it has a 4.5 to 40V enter vary with (load-dump) safety to 45V and reverse-connection safety to -40V.

The output voltage is adjustable by a pair of resistors (100kΩmin) throughout 1.5 to 20V – offering there’s sufficient enter voltage – and the utmost output present might be set between a couple of mA and 300mA by one other exterior resistor.

‘Vcc’ (see diagram) is an output linked to the chip’s inside regulated 4.5V rail. It wants a capacitor, and may provide as much as 15mA to exterior circuits.

Connecting the voltage feed-back pin to floor apparently converts the gadget right into a current-limited change – presumably by means of the offered output allow pin – the info sheet will not be utterly clear right here, by my studying.

Drop-out is 500mVmax with a 100mA load, and it’s steady with output capacitors throughout 1.2 to 100µF and 1mΩ to 5Ω ESR. PSSR is usually 73dB at 100Hz.

Reverse circulation safety comes from together with a second p-channel collection move ingredient, managed by its personal circuit, back-to-back with the principle voltage regulator p-channel mosfet (see diagram).

The on-resistance of this further mosfet doubles because the regulator’s high-side current-sense resistor, and a further characteristic is that it has an analogue output that may present present info to an exterior MCU in order that it may discriminate between regular circumstances, output open-circuit or short-circuit. By way of an allow enter on the regulator, the MCU can activate and off this analogue output, permitting the MCU it to multiplex the sensed currents from a number of comparable regulators in to itself although solely one in all its analogue pins – and the expense of utilizing up digital output pins.

Protections not but talked about embrace: thermal shut-down, under-voltage lock-out, output short-circuit and output short-to-battery, and the output has inside clamp safety towards transients from switching off inductive masses. An error output flags a few of these states to the host MCU.

Operation is over -40°C to +125°C and packaging is a 5 x 6.5mm 16pin thermal-pad TSSOP.

One other level to TI.

The TPS7B7701-Q1 might be discovered right here, and there’s an eval board for the twin model

 





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