TLC555: Frequency Behavior Differences

Francis Jiang

Part Number: TLC555
Other Parts Discussed in Thread: TLC3555-Q1, , , TLC3555

Hi Team,

Could you please help share the spec differences between pre-PCN device and post-PCN device?

Especially for the tPLH & tPHL, there is a highly different ~31.5% between these 2 series device on customer board(frequency behavior, with the same peripheral circuit).

Thanks.

BRs,

Francis

3 months ago

+1 Ron Michallick 3 months ago

TI__Guru**** 173766 points

Hello Francis,

See this FAQ , [FAQ] TLC555: performance differences PCN 20231130002.1 Bullet #1, Lower propagation delays so a-stable oscillator will have a higher output frequency

A new PCN is coming that restores legacy propagation delays and output frequency.

For hundreds of kilohertz, TLC3555-Q1 is recommended. It is faster and it has no performance changing PCN implemented or planned.

0 Francis Jiang 3 months ago in reply to Ron Michallick

TI__Expert 4410 points

Hi Ron,

Thanks for your detailed reply.

So whether the fast PCN device and slow PCN device will exist simultaneously?

Thanks.

BRs,

Francis

+1 Ron Michallick 3 months ago in reply to Francis Jiang

TI__Guru**** 173766 points

Francis,

TLC555 commercial (not Q1) can be a mix of original and faster; later also close to original.

TLC555-Q1 is original; later also close to original.

TLC3555-Q1 is original 3555 (always faster)

0 Francis Jiang 3 months ago in reply to Ron Michallick

TI__Expert 4410 points

Hi Ron,

Sorry for trouble, I am confused by these version numbers.

Please let me mark:

TLC555

pre-PCN TLC555 as TLC555_0
post-PCN TLC555 as TLC555_1
the later also close to original as TLC555_2

TLC555-Q1

pre-PCN TLC555-Q1 as TLC555-Q1_0
later post-PCN TLC555-Q1 as TLC555-Q1_1

_____________________________________

So you mean TLC555_1 will mix, right? Even TLC555_2 is released.

Customer would like to know the schedule of TLC555_2, and firstly they don't want to consider the TLC555-Q1.

Thanks.

BRs,

Francis

+1 Ron Michallick 3 months ago in reply to Francis Jiang

TI__Guru**** 173766 points

Francis,

Francis Jiang said:
Customer would like to know the schedule of TLC555_2, and firstly they don't want to consider the TLC555-Q1.

Great, that makes thing easier to explain. This is the schedule for the 2nd PCN.

The 1st PCN, 20231130002.1, is already released.

For spec changes, 1st PCN is reason for data sheet revision J (from I); 2nd PCN is reason for data sheet revision K (from J). Page 26 of current data sheet lists these changes.

0 Francis Jiang 3 months ago in reply to Ron Michallick

TI__Expert 4410 points

Hi Ron,

Customer would like to ask for the spec comparison table between TLC555_0 & TLC555_2. Especially tphl & tplh. Could you please help here? Thanks a lot.

BRs,

Francis

+1 Ron Michallick 3 months ago in reply to Francis Jiang

TI__Guru**** 173766 points

Francis,

TLC555_0

TLC555_2 , biggest difference is below 4V , far flatter curve

0 Francis Jiang 3 months ago in reply to Ron Michallick

TI__Expert 4410 points

Hi Ron,

Customer tested TLC555_2 and it also has 10% error compares with TLC555_0. As TLC555_0 is ~250kHz, TLC555_2 is ~280kHz. Also quite large.

They consider testing TLC3555 now, and would like to firstly evaluate the post-PCN of TLC3555, could you please also attach the comparison table here for their reference? Thanks in advance.

BRs,

Francis

+1 Ron Michallick 3 months ago in reply to Francis Jiang

TI__Guru**** 173766 points

Francis,

+12% is better than +32%, but it is still a shift.

Francis Jiang said:
They consider testing TLC3555 now, and would like to firstly evaluate the post-PCN of TLC3555,

This is the best part. TLC3555 did not have a performance changing PCN and no PCN is planned or foreseeable.

For a more consistent output frequency, TLC3555 will be much better. As good or better than the original TLC555 was in the past.

TLC3555 will need the timing component(s) modified to set the frequency.

Clock & timing

Clock & timing forum

TLC555: Frequency Behavior Differences