SWRZ149B July   2023  – December 2025 IWRL1432

PRODUCTION DATA  

  1.   1
  2. 1Introduction
  3. 2Device Nomenclature
  4. 3Device Markings
  5. 4Usage Notes
    1. 4.1 Power up sequence in power optimized topology
    2. 4.2 Meeting data sheet spec for 1.2V Digital LDO output path in BOM optimized topology
  6. 5Advisory to Silicon Variant / Revision Map
  7. 6Known Design Exceptions to Functional Specifications
    1. 6.1  ANA #51
    2. 6.2  ANA #52
    3. 6.3  DIG #1
    4. 6.4  DIG #2
    5. 6.5  DIG #3
    6. 6.6  DIG #4
    7. 6.7  DIG #5
    8. 6.8  DIG #6
    9. 6.9  DIG #7
    10. 6.10 DIG #8
    11. 6.11 DIG #9
    12. 6.12 DIG #10
    13. 6.13 DIG #14
    14. 6.14 DIG #15
    15. 6.15 DIG #16
  8. 7Trademarks
  9.   Revision History

4.2 Meeting data sheet spec for 1.2V Digital LDO output path in BOM optimized topology

As indicated in the device data sheet,1.2V Digital LDO requires one decoupling capacitor with a typical value of 4.7uF. The parasitic offered by different portion of the output path is illustrated in Figure 4-2. “RT1” and “RT2” are parasitic resistances offered by the ball to capacitor lead trace and the ground trace, respectively. Similarly, “LT1” and “LT2” are parasitic inductances offered by the ball to capacitor lead trace and the ground trace, respectively. “ESL1” and “ESR1” are the effective series inductance and resistance of the decoupling capacitor. Table 4-1 gives the minimum, maximum and typical values of the capacitance and the parasitic.

IWRL1432 Single decoupling capacitor associated PCB parasitic Figure 4-2 Single decoupling capacitor associated PCB parasitic

Table 4-1 1.2V Dig LDO Output
Min Typ Max Unit
Recommended value of C 3.6 4.7 5.2 uF
Allowed output parasitic inductance Lp 1 1.5 2 nH
Allowed output parasitic resistance Rp 15 20 35 mOhm
If the RP is not achievable in PCB design, below workarounds can be considered:

Add a series precision resistor in the VDD output path along with the decoupling capacitor to get equivalent effective series resistance of the output path within the data sheet limits.

Example part no.: PA0402FRL570R02L, 20mOhm, 1% Tol.; MFL0603R0200FA, 20mOhm, 1% Tol;

IWRL1432 Example workaround Figure 4-3 Example workaround