I’ll proceed one verified step at a time. First, I’m only checking the handheld’s current routing state and fresh DRC results; I won’t modify anything until that exact baseline is known.
Worked for 17 sec
flux
11 days ago
Baseline complete: 9 airwires, 1 copper overlap, and 6 ERC errors. Following the required order, I’ll fix only the single P1 copper overlap next, then rerun that one check before touching routing.
Worked for 7 mins 6 sec
flux
11 days ago
First step complete: the P1 copper overlap is fixed and verified.
Replaced the offending HH_ILIM trace with a clearance-safe route.
No components or protected USB-C differential copper were changed.
Next step: I’ll route only the RXD airwire, keep all placement fixed, and then rerun the airwire and copper checks before proceeding further.
Thought for 9 mins 48 sec
flux
11 days ago
The RXD routing attempt was blocked by local congestion. The test route was fully reverted, leaving the board unchanged at 9 airwires and 0 copper overlaps.
Next single step requires approval: reduce RXD only from 0.15 mm to 0.13 mm trace width to create a legal escape path without moving components. Approve this rule adjustment?
Calculation-backed planning budget for the repaired handheld and receiver schematic. Duty cycle, RF range, thermal behavior, and machine-interface behavior remain measurement items.
Handheld Duty-Cycle Model
Table
Mode
Duty
Planning current
Weighted current
RAK3172 sleep
84%
0.00169 mA
0.0014 mA
RAK3172 receive
15%
5.22 mA
0.783 mA
RAK3172 transmit at 20 dBm
1%
87 mA
0.870 mA
Weighted radio
100%
1.654 mA
Table
Additional 3.3 V load
Planning average
DOGM162 display logic
0.250 mA
MAX17048 fuel gauge
0.040 mA
TPS63031 conversion/overhead allowance
0.050 mA
Encoder pull-ups, status indication, leakage, miscellaneous
0.150 mA
Calculated 3.3 V average
2.144 mA
20% margin
0.429 mA
Budgeted 3.3 V average
2.573 mA
At 3.7 V nominal battery and 88% efficiency:
I_BAT_AVG = 3.3 V × 2.573 mA / (3.7 V × 0.88) = 2.61 mA
Twelve hours requires approximately 31.3 mAh. With a 2× field reserve and 70% usable rated capacity, the planning minimum is approximately 89 mAh.
Selected Battery and Charging
Selected pack basis: EEMB LP502030, protected 1S LiPo, 3.7 V nominal, 250 mAh, approximately 20.5 × 32 × 5.3 mm.
Planning limits from the manufacturer information:
Maximum charge current: 250 mA.
Maximum discharge current: 500 mA.
Existing BQ24074 fast-charge setting: approximately 201 mA from R3 = 4.42 kΩ.
Charge termination: approximately 20 mA from R5 = 3.0 kΩ.
Runtime at 70% usable capacity is approximately:
250 mAh × 0.70 / 2.61 mA = 67 hours
This is not a release claim. Final firmware, cold temperature, aging, self-discharge, and protection-circuit cutoff must be measured.
Peak-Current Reconciliation
Approximately 90 mA is the 3.3 V rail peak for radio TX plus support loads.
At 3.0 V battery and 85% conversion efficiency, this reflects to approximately 116 mA battery current.
The previously stated 250 mA was a conservative minimum continuous/pulse pack qualification target, not the predicted operating peak.
The selected pack's 500 mA maximum discharge rating provides margin over the estimated 116 mA peak.
Simultaneous charge and operation, USB input current, enclosure temperature rise, and cold-cell voltage sag remain mandatory tests.
Receiver Load Budget
Table
Load
Source rail
Planning current
RAK3172 receiver MCU/radio
3.3 V
100 mA peak
TPS3431, indicators, logic margin
3.3 V
20 mA
ADuM1401 logic side
3.3 V
10 mA
Isolated analog converter input
5 V
80 mA provisional
3.3 V LDO load reflected to 5 V
5 V
120 mA peak
LM5164 5 V design load
5 V
250 mA
The isolated allowance includes U15/U13, two U18 input LEDs, the U19 isolated output stage, U20 monitor LED, and associated bias currents.
At 5 V/0.25 A and 80% efficiency, estimated LM5164 input current is approximately 130 mA at 12 V, 65 mA at 24 V, and 33 mA at 48 V.
Receiver Power-Stage Basis
Protected continuous input: 12–48 VDC; 58 V maximum non-transient.
LM5164 frequency target: approximately 303 kHz.
Feedback: 316 kΩ / 100 kΩ, approximately 4.99 V.
UVLO: approximately 10.1 V turn-on and 9.45 V turn-off.
L10 requirement: 150 µH shielded, Isat ≥2.1 A, thermal current ≥1.5 A, DCR ≤0.25 Ω, -40 to +125 °C.
The ≥2.1 A saturation requirement is based on margin above the LM5164 1.75 A maximum current-limit threshold, not on the 250 mA normal load.
Input capacitance: two 2.2 µF, 100 V ceramics. Output capacitance: 22 µF with voltage rating appropriate to the 5 V rail.
U15 bulk capacitors: 10 µF on ISO_12V rated at least 25 V and 10 µF on ISO_5V rated at least 10 V, with local 100 nF bypassing.
Required Validation
Measure handheld sleep, receive, display, encoder-active, and TX currents in final firmware.
Run 12-hour representative, cold-cell, aged-cell, and simultaneous-charge tests on received LP502030 packs.
Verify battery connector polarity and protection behavior on every approved source.
Measure receiver startup, ripple, switch-node behavior, and temperature at 12, 24, and 48 V.
Short/fault-test the buck stage to confirm L10 does not saturate before current limiting protects the converter.
Validate isolated-rail collapse/recovery while monitoring ISO_OUTPUT_ARMED, U15 RESET, U18 inputs, and machine-terminal outputs.
Fault-inject the machine A terminal through the simulator and confirm the approximately 10 kΩ effective path and D15 clamp keep AD5293 terminal current within the authoritative datasheet limit.
Verify the 0.5 A fuses clear safely without connector or trace damage.