noisedestroyers/rpicarrierboard
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Power stage 3: LM61460-Q1 15V->+3V3_RF 4A buck; EN from CM5 PCIE_PWR_EN

Browse Source 
- Second LM61460-Q1 (U_BUCK33R), FB 23.2k/10.0k -> 3.32V (SPICE: vfb 0.994V,
  inrush settles 3.32V); shared BOM with stage 2 (L 4.7uH/7A, RT 31.6k ~420kHz)
- BIAS -> +3V3_RF (datasheet-valid >=3.1V, falls back to VIN below)
- EN <- PCIE_PWR_EN: Module1 pin 106 NC swapped for a global label on
  CM5_HighSpeed + 100k pull-down (mirrors reference R14) so the Wi-Fi rail
  stays off until CM5 asserts it; netlist-verified 3-node net
- Removed the E-key temp PWR_FLAG (#FLG33RF); buck PWR_FLAG on L33.2 is now
  the sole +3V3_RF driver
- Verify: ERC 133->133 zero new; analyzer +49/-0 zero regressions;
  SPICE 17 pass / 2 benign warn / 0 fail

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
This commit is contained in:
noise
2026-07-01 22:11:24 -04:00
parent d72f3a4bd8
commit 261bf48bb4
6 changed files with 594 additions and 41 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
tools/build_power.py
View File

@@ -101,7 +101,7 @@ register_lm61460()
# +5v pre-exists in the carrier as a HIERARCHICAL net (local + hierarchical labels on the CM5
# sheets) -> expose it hierarchically here (a global label collides: same_local_global_label).
# +3V3_RF/+3V3_AUX are new nets introduced by this port -> global is fine.
GLOBAL_NETS = {"+3V3_RF", "+3V3_AUX"}
GLOBAL_NETS = {"+3V3_RF", "+3V3_AUX", "PCIE_PWR_EN"}
HIER_NETS = {"+5v"}
# from KiCad libs (renamed to full lib_id)
add_from("power:PWR_FLAG", open(f"{KSS}/power.kicad_sym").read(), "PWR_FLAG")
@@ -207,6 +207,32 @@ place("Device:C", "C_OUT5b", "47u/16V", "Capacitor_SMD:C_1210_3225Metric", 180,
# +5v is now sourced by this buck -> PWR_FLAG co-located on L5 pin2 (+5v)
p5x, p5y = pin_abs(l5, "Device:L", "2"); emit_flag(p5x, p5y, "P5V")
# ---- STAGE 3: U_BUCK33R 15V -> +3V3_RF 4A (LM61460-Q1, sync) --------------------
# FB divider: VREF=1.0V -> Rfbt/Rfbb=2.32 -> 23.2k/10.0k = 3.32V.
# Same support set as stage 2 (RT 31.6k ~420kHz, L 4.7uH/7A: ripple ~1.3A = 33% of 4A).
# BIAS -> +3V3_RF (datasheet: BIAS>=3.1V uses output LDO path; falls back to VIN below).
# EN <- PCIE_PWR_EN (CM5 Module1 pin 106, global net) + 100k pull-down (= reference R14)
# so the Wi-Fi rail stays OFF until the CM5 asserts it.
place("CM5IO:LM61460-Q1", "U_BUCK33R", "LM61460-Q1", "Package_SO:Texas_HTSSOP-14-1EP_4.4x5mm_P0.65mm_EP3.4x5mm_Mask3.155x3.255mm_ThermalVias",
230, 150, {'8': 'VIN_PROT', '12': 'VIN_PROT', '7': 'PCIE_PWR_EN', '1': '+3V3_RF', '2': 'VCC33',
'6': 'RT33', '5': 'PG33', '4': 'FB33', '10': 'SW33', '14': 'BOOT33', '13': 'RBOOT33',
'9': GND, '11': GND, '3': GND, '15': GND})
l33 = place("Device:L", "L33", "4.7uH/7A", "Inductor_SMD:L_Bourns_SRP1245A", 270, 138, {'1': 'SW33', '2': '+3V3_RF'})
place("Device:C", "C_BOOT33", "100n", "Capacitor_SMD:C_0402_1005Metric", 260, 132, {'1': 'SW33', '2': 'BOOT33'})
place("Device:R", "R_BOOT33", "4.7", "Resistor_SMD:R_0402_1005Metric", 265, 128, {'1': 'RBOOT33', '2': 'BOOT33'})
place("Device:R", "R_RT33", "31.6k", "Resistor_SMD:R_0402_1005Metric", 210, 158, {'1': 'RT33', '2': GND})
place("Device:R", "R_PG33", "100k", "Resistor_SMD:R_0402_1005Metric", 255, 143, {'1': 'PG33', '2': '+3V3_RF'})
place("Device:R", "R_FBT33", "23.2k", "Resistor_SMD:R_0402_1005Metric", 285, 150, {'1': '+3V3_RF', '2': 'FB33'})
place("Device:R", "R_FBB33", "10.0k", "Resistor_SMD:R_0402_1005Metric", 285, 158, {'1': 'FB33', '2': GND})
place("Device:R", "R_EN33", "100k", "Resistor_SMD:R_0402_1005Metric", 200, 165, {'1': 'PCIE_PWR_EN', '2': GND})
place("Device:C", "C_VCC33", "1u", "Capacitor_SMD:C_0402_1005Metric", 220, 158, {'1': 'VCC33', '2': GND})
place("Device:C", "C_IN33a", "10u/50V", "Capacitor_SMD:C_1210_3225Metric", 215, 145, {'1': 'VIN_PROT', '2': GND})
place("Device:C", "C_IN33b", "10u/50V", "Capacitor_SMD:C_1210_3225Metric", 220, 145, {'1': 'VIN_PROT', '2': GND})
place("Device:C", "C_OUT33a", "47u/16V", "Capacitor_SMD:C_1210_3225Metric", 240, 165, {'1': '+3V3_RF', '2': GND})
place("Device:C", "C_OUT33b", "47u/16V", "Capacitor_SMD:C_1210_3225Metric", 245, 165, {'1': '+3V3_RF', '2': GND})
# +3V3_RF is now sourced by this buck -> PWR_FLAG on L33 pin2 (replaces the E-key temp flag)
p33x, p33y = pin_abs(l33, "Device:L", "2"); emit_flag(p33x, p33y, "P33R")
# ---- file scaffold ----------------------------------------------------------------
libsyms = "\n".join(blk for blk, _ in LIBS.values())
sheet = ('(kicad_sch\n\t(version 20231120)\n\t(generator "eeschema")\n\t(generator_version "8.0")\n'