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SPICE subcircuitSparkFun BOB-12009bss138_ls4

Level shifter 4-ch (BSS138, bidirectional)

Bidirectional logic level converter module with 4 channels: one BSS138 MOSFET and two 10 kΩ pull-ups per channel (NXP AN10441). LV = low supply (e.g. 3.3 V), HV = high supply (e.g. 5 V); for I²C, UART, slow SPI. Rise time set by the 10 kΩ pull-ups and the line capacitance.

LVLV1LV2LV3LV4HVHV1HV2HV3HV4GNDSparkFun BOB-12009
Schematic symbol

Key data

Category
Modules
Simulation model
SPICE subcircuit
Manufacturer part number
SparkFun BOB-12009
Reference prefix
U
Pins
11
Land pattern
PinHeader_1x12_P2.54mm_Vertical

Notes

  • Use it for I²C, UART and slow SPI (up to about 1 MHz with the 10 kΩ pull-ups). Both sides need their supply connected.

Simulation model

The part is a small SPICE netlist (below), solved by the analog engine together with the rest of the circuit. Pin ids are the node names, {braces} are parameters.

SPICE netlist
RL1 LV LV1 10k
RH1 HV HV1 10k
M1 HV1 LV LV1 LV1 NMOS_BSS138
D1 LV1 HV1 DBSS138
RL2 LV LV2 10k
RH2 HV HV2 10k
M2 HV2 LV LV2 LV2 NMOS_BSS138
D2 LV2 HV2 DBSS138
RL3 LV LV3 10k
RH3 HV HV3 10k
M3 HV3 LV LV3 LV3 NMOS_BSS138
D3 LV3 HV3 DBSS138
RL4 LV LV4 10k
RH4 HV HV4 10k
M4 HV4 LV LV4 LV4 NMOS_BSS138
D4 LV4 HV4 DBSS138
.model NMOS_BSS138 NMOS(VTO=1.3 KP=0.052 LAMBDA=0.01 CGS=21p CGD=6p)
.model DBSS138 D(IS=1e-12 N=1 RS=1.61 BV=50 IBV=10u)

Pins 11

PinNameUse
LVLVSupply pinLow-voltage supply (e.g. 3.3 V): gate of the MOSFETs and LV pull-ups
LV1LV1I/O pin · pulled up on the boardSignal on the low-voltage side (to the 3.3 V device), 10 kΩ pull-up to LV
LV2LV2I/O pin · pulled up on the boardSignal on the low-voltage side (to the 3.3 V device), 10 kΩ pull-up to LV
LV3LV3I/O pin · pulled up on the boardSignal on the low-voltage side (to the 3.3 V device), 10 kΩ pull-up to LV
LV4LV4I/O pin · pulled up on the boardSignal on the low-voltage side (to the 3.3 V device), 10 kΩ pull-up to LV
HVHVSupply pinHigh-voltage supply (e.g. 5 V): HV pull-ups
HV1HV1I/O pin · pulled up on the boardSignal on the high-voltage side (to the 5 V device), 10 kΩ pull-up to HV
HV2HV2I/O pin · pulled up on the boardSignal on the high-voltage side (to the 5 V device), 10 kΩ pull-up to HV
HV3HV3I/O pin · pulled up on the boardSignal on the high-voltage side (to the 5 V device), 10 kΩ pull-up to HV
HV4HV4I/O pin · pulled up on the boardSignal on the high-voltage side (to the 5 V device), 10 kΩ pull-up to HV
GNDGNDGround pinGround

PCB

Verified land patternPinHeader_1x12_P2.54mm_Vertical
PackageLand patternStatusSource
modulePinHeader_1x12_P2.54mm_VerticalVerified land patternmodule on a 2.54 mm pin header, LV1, LV2, LV, GND, LV3, LV4, HV1, HV2, HV, GND, HV3, HV4 (SparkFun BOB-12009 order: compare with your module)