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AR# 47443

Design Advisory for 7 Series FPGA GTH Transceiver Power-Up/Power-Down

Description

This answer record discusses the 7 series GTH Transceiver power-up/power-down sequencing recommendations.

Solution

1) Recommended power-up/power-down sequence:

The recommended GTH transceiver power-on sequence is VCCINT, VMGTAVCC, VMGTAVTT or VMGTAVCC, VCCINT, VMGTAVTT to achieve minimum current draw. There is no recommended sequencing for VMGTVCCAUX. Both VMGTAVCC and VCCINT can be ramped up simultaneously. The recommended power-off sequence is the reverse of the power-on sequence to achieve minimum current draw.

If the recommended sequences are not met, current drawn from VMGTAVTT can be higher than specifications during power-up and power-down:

  • When VMGTAVTT is powered up before VMGTAVCC, and VMGTAVTT - VMGTAVCC > 150 mV and VMGTAVCC < 0.7V, the VMGTAVTT current draw can increase by 460 mA per transceiver when VMGTAVCC is ramping up. The duration of the current draw can be up to 0.3* TMGTAVCC (ramp time from GND to 90% of VMGTAVCC).
  • When VMGTAVTT is powered up before VCCINT , and VMGTAVTT - VCCINT > 150 mV and VCCINT < 0.7V, the VMGTAVTT current draw can increase by 50 mA per transceiver when VCCINT is ramping up. The duration of the current draw can be up to 0.3* TVCCINT (ramp time from GND to 90% of VCCINT).
  • When VMGTAVCC is powered down before VMGTAVTT, and VMGTAVTT - VMGTAVCC > 150 mV and VMGTAVCC < 0.7V, the VMGTAVTT current draw can increase by 460 mA per transceiver when VMGTAVCC is ramping down. The duration of the current draw can be up to 0.3* TMGTAVCC (ramp time from 100% to 10% of VMGTAVCC).
  • When VCCINT is powered down before VMGTAVTT , and VMGTAVTT - VCCINT > 150 mV and VCCINT < 0.7V, the VMGTAVTT current draw can increase by 50 mA per transceiver when VCCINT is ramping down. The duration of the current draw can be up to 0.3* TVCCINT (ramp time from 100% to 10% of VCCINT).

2) For the 7 Series GTH Transceiver Initial and General ES Silicon ONLY

If the recommended power-up sequence is followed, while VMGTAVCC is powered within its recommended operating range and VMGTAVTT is below 0.7V, an additional 70 mA per GTH transceiver is drawn from VMGTAVCC. Depending on the number of transceivers used, this extra current could be greater than reported in XPE.

Follow this procedure to determine if the power supply regulator for VMGTAVCC is sufficient:

  1. Refer to Table 1: Virtex-7 FPGA GTX/GTH Transceiver Power Supply Grouping Per Package to determine the total number of QUADs per power supply grouping.
  2. Refer to Table 2: Total GTH VMGTAVCC Current for Number of QUADs in a Power Supply Grouping to determine the maximum VMGTAVCC current per power supply grouping.
  3. Calculate the VMGTAVCC power consumption per power supply grouping based on the number of transceivers used that are utilizing XPE in the GTH tab.
  4. If the current value obtained from XPE in Step 3 is greater than or equal to the current value obtained in Step 2, no change is required.
  5. If the current value obtained from XPE in Step 3 is less than the current value obtained in Step 2, it is recommended that the power supply regulator for VMGTAVCC be enhanced to account for this extra current.


Table 1: Virtex-7 FPGA GTX/GTH Transceiver Power Supply Grouping Per Package

MGTMGTMGTMGTMGTMGTMGTMGTMGTMGTMGTMGT
210211212213214215216217218219220221
110111112113114115116117118119120121
XC7V585T-FFG1157 G10G10
(RCAL)
G10G11G11
XC7V585T-FFG1761 G10G10G10G10G10
(RCAL)
G10G11G11G11
XC7V2000T-FHG1761 G10G10
(RCAL)
G10G10G10
(RCAL)
G10G11G11
(RCAL)
G11
XC7V2000T-FLG1925 G10
(RCAL)
G10G11G11
(RCAL)
XC7VX330T-FFG1157 G10G10
(RCAL)
G10G11G11
XC7VX330T-FFG1761 G10G10G10
(RCAL)
G10G11G11G11
XC7VX415T-FFG1157 G10G10
(RCAL)
G10G11G11
XC7VX415T-FFG1158Left-side G20G20
(RCAL)
G20G21G21G21
Right-side G10G10
(RCAL)
G10G11G11G11
XC7VX415T-FFG1927Left-side G20G20
(RCAL)
G20G21G21G21
Right-side G10G10
(RCAL)
G10G11G11G11
XC7VX485T-FFG1157Left-side
Right-side G10G10
(RCAL)
G10G11G11
XC7VX485T-FFG1761Left-side
Right-side G10G10G10
(RCAL)
G10G11G11G11
XC7VX485T-FFG1158Left-side G20G20
(RCAL)
G20G21G21G21
Right-side G10G10
(RCAL)
G10G11G11G11
XC7VX485T-FFG1927Left-side G20G20G20
(RCAL)
G20G21G21G21
Right-side G10G10G10
(RCAL)
G10G11G11G11
XC7VX485T-FFG1930Left-side
Right-side G10G10G10G11
(RCAL)
G11G11
XC7VX550T-FFG1158Left-side G20G20
(RCAL)
G20G21G21G21
Right-side G10G10
(RCAL)
G10G11G11G11
XC7VX550T-FFG1927Left-sideG19G19G19G20G20G20
(RCAL)
G20G21G21G21
Right-sideG9G9G9G10G10G10
(RCAL)
G10G11G11G11
XC7VX690T-FFG1157Left-side
Right-side G10G10
(RCAL)
G10G11G11
XC7VX690T-FFG1761Left-side
Right-side G10G10G10G10G10
(RCAL)
G10G11G11G11
XC7VX690T-FFG1158Left-side G20G20
(RCAL)
G20G21G21G21
Right-side G10G10
(RCAL)
G10G11G11G11
XC7VX690T-FFG1926Left-side G20G20G21G21G21
(RCAL)
G22G22G22
Right-side G10G10G11G11G11
(RCAL)
G12G12G12
XC7VX690T-FFG1927Left-sideG19G19G19G20G20G20
(RCAL)
G20G21G21G21
Right-sideG9G9G9G10G10G10
(RCAL)
G10G11G11G11
XC7VX690T-FFG1930Left-side
Right-side G10G10G10
(RCAL)
G11G11G11
XC7VX980T-FFG1926Left-side G20G20G21G21G21
(RCAL)
G22G22G22
Right-side G10G10G11G11G11
(RCAL)
G12G12G12
XC7VX980T-FFG1928Left-sideG20G20G20
(RCAL)
G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-sideG10G10G10
(RCAL)
G11G11G11
(RCAL)
G12G12G12
(RCAL)
XC7VX980T-FFG1930Left-side
Right-side G10G10G10
(RCAL)
G11G11G11
XC7VX1140T-FLG1926Left-side G20G20
(RCAL)
G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-side G10G10
(RCAL)
G11G11G11
(RCAL)
G12G12G12
(RCAL)
XC7VX1140T-FLG1928Left-sideG20G20G20
(RCAL)
G21G21G21
(RCAL)
G22G22G22
(RCAL)
G23G23G23
(RCAL)
Right-sideG10G10G10
(RCAL)
G11G11G11
(RCAL)
G12G12G12
(RCAL)
G13G13G13
(RCAL)
XC7VX1140T-FLG1930Left-side
Right-side G10G10G10
(RCAL)
G11G11G11
(RCAL)
XCV7H580T-HCG1155Left-side G20G20G20
(RCAL)
Right-side G10G10G10
(RCAL)
XCV7H580T-HCG1931Left-side G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-side G11G11G11
(RCAL)
G12G12G12
(RCAL)
XCV7H580T-HCG1932Left-side G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-side G11G11G11
(RCAL)
G12G12G12
(RCAL)
XCV7H870T-HCG1931Left-side G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-side G11G11G11
(RCAL)
G12G12G12
(RCAL)
XCV7H870T-HCG1932Left-sideG20G20G20
(RCAL)
G21G21G21
(RCAL)
G22G22G22
(RCAL)
Right-sideG10G10G10
(RCAL)
G11G11G11
(RCAL)
G12G12G12
(RCAL)

Notes:

  1. Power pins and pin-out for QUAD113 and QUAD213 are made available for seamless migration/swapping to the XC7VX485T, XC7VX550T and the XC7VX690T.
  2. Power pins and pin-out for QUAD110, QUAD210, QUAD111 and QUAD211 are made available for seamless migration/swapping to the XC7VX550T.

Table 2: Total GTH VMGTAVCC Current for Number of QUADs in a Power Supply Grouping

Number of QUADs in a Power Supply Group

VMGTAVCC Current per Power Supply Group (mA)

6

1680

4

1120

3

840

2

560

1

280

3) Frequently Asked Questions:


1) Simultaneous power-up: Is it okay to simultaneously power-up VMGTAVCC and VMGTAVTT, or VCCINT and VMGTAVTT, or all three? Does the additional current draw still apply?

During power-up, if VMGTAVCC < 0.7V (Time "T1" in the picture) and VMGTAVTT - VMGTAVCC <= 150 mV, then there is no additional current draw. During power-up, if VMGTAVCC >= 0.7V (Time "T1" in the picture), then there is no additional current irrespective of VMGTAVTT value.

During power-up, if VMGTAVCC < 0.7V (Time "T1" in the picture) and VMGTAVTT VCCINT <= 150 mV, then there is no additional current draw. During power-up, if VCCINT >= 0.7V (Time "T1" in the picture), then there is no additional current irrespective of VMGTAVTT value.

If these conditions cannot be met, then the additional current needs to be accounted for.


 

2) Are these additional currents on VMGTAVTT cumulative when both sequences of VMGTAVTT vs VMGTAVCC and VMGTAVTT vs VCCINT are not followed?

The power supply current increase is cumulative. So if both conditions occur simultaneously, the total is 510 mA extra on VMGTAVTT.


3) What is the impact of this additional current and when does this happen?

This additional current happens only on the power-up and power-down ramp. Once the GTH transceivers are powered up and running, then this has no impact.


4) What are the key things to keep in mind for the recommended power sequencing to avoid the additional current draw?

VMGTAVTT must be powered up last. VMGTAVCC and VCCINT must be powered up before VMGTAVTT but they can be in any order. VMGTAVCCAUX has no recommended sequencing. These are the criterion that ensure the recommended sequencing is met and there is no current draw.

Revision History

10/20/2016Added conditions for additional current draw during power-down
11/09/2012Updated Table 1 with the latest information to include all Virtex-7 devices and packages.
08/22/2012Added a note that section (2) applies to Initial and General ES GTH silicon only.
08/17/2012Updated the VMGTAVTT additional current draw value to 460 mA When VMGTAVTT is powered before VMGTAVCC, and VMGTAVTT - VMGTAVCC > 150 mV and VMGTAVCC < 0.7V.
07/19/2012More clarification added - Updated with information about duration of current draw, simultaneous power-up and more FAQs.
06/08/2012Added the power sequencing recommendations and the FAQ section.
05/23/2012Updated the title to say transceiver power-up.
05/02/2012Initial release

Linked Answer Records

Associated Answer Records

Answer Number Answer Title Version Found Version Resolved
42944 Design Advisory Master Answer Record for Virtex-7 FPGA N/A N/A
AR# 47443
Date Created 04/25/2012
Last Updated 10/28/2016
Status Active
Type Design Advisory
Devices
  • Virtex-7