LM2904B-Q1: LM2904B-Q1 similar device with one channel recommendation

Jessica Wu74

Part Number: LM2904B-Q1
Other Parts Discussed in Thread: LM2904-Q1, TS321-Q1, TL971-Q1, TLV9151-Q1, TLV9351-Q1, LM2904B

Hi Team,

Could you please kindly help to check if we have other lower cost device which is similar with LM2904B-Q1 with only one channel. For customer application, they want a one channel device which support ±5V supply. And for the suitable device which your team recommend, could you please also help to provide the ±5V current consumption and ripple requirement? Since customer need to consider the ±5V power supply ripple and load requirement. From another side, could you please also kindly help to check if we have relate ±5V power supply circuit design which also could recommend to customer? Thanks a lot for your support.

Best regards

Jie

6 months ago

0 Ron Michallick 6 months ago

TI__Guru*** 142736 points

Hello Jie,

https://www.ti.com/amplifier-circuit/op-amps/products.html#480=1&1498=Automotive&1261max=10%3B180&sort=1130;asc&

Single, 10V, Q1 makes TL0971-Q1 the lowest cost. It is common to get LM2904B-Q1 and use just one side. The other side can be unused see [APP] Design Guidelines for Devices with LM324/LM358 Cores

For the +/-5V supply , is the input power +10.5V to +14.5V (or similar)? How much load current?

0 Clemens Ladisch 6 months ago

Guru 258400 points

The TS321-Q1 has exactly the same characteristics as the LM2904-Q1. But there is no -B model.

The TL971-Q1 does not have rail-to-rail inputs. If you are using input voltages near −5 V, use the TLV9151-Q1 or TLV9351-Q1.

0 Jessica Wu74 6 months ago in reply to Clemens Ladisch

TI__Expert 4040 points

Hi Ron, Clemens

Thanks a lot for your feedback. Customer would like to use LM2904B-Q1 in this case.

For customer application, they would like us LM2904B do a voltage follow up circuit in their application, and for the output current of LM2904B-Q1, customer still not sure, based on this condition, could you please kindly help to check what is the worse case of LM2904B-Q1 load current? Under this kind of condition, we could know how to choice the power supply(±5V) capacity. And for the ±5V ripple for LM2904B-Q1, is there has any special requirement? Currently we find a device which could generate -5V power, but with 20mV ripple, if this is ok for LM2904B-Q1 to work normally? Thanks again for your help to double check.

Best regards

Jie

0 Clemens Ladisch 6 months ago in reply to Jessica Wu74

Guru 258400 points

This schematic does not show a voltage follower; the inverting and non-inverting input pins are exchanged.

In this circuit, the load of U1 is determined by the feedback resistors R1 and R6, i.e., it is negligible.

But note that the LM2904B-Q1 has an input bias current of up to 50 nA that always flows out of the input pins; it might generate a voltage drop of up to 75 mV over RstN or RstP. If this is too large for you, use a CMOS opamp instead.

The LM2904B-Q1 specifies the power supply rejection ratio (PSRR) as less than 15 µV/V, i.e., 20 mV supply ripple results in less than 0.3 µV output ripple.

0 Jessica Wu74 6 months ago in reply to Clemens Ladisch

TI__Expert 4040 points

Hi Clemens,

Thanks a lot for your feedback. It helps a lot for your suggestions. could you please kindly help to recommend a CMOS opamp, since the 75mv drop on Rstp/Rstn is too large. Thanks again for your support.

Best regards

Jie

0 Clemens Ladisch 6 months ago in reply to Jessica Wu74

Guru 258400 points

TLV9151-Q1, TLV9351-Q1.

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LM2904B-Q1: LM2904B-Q1 similar device with one channel recommendation