L293D motor driver shield: specs and pinout
A shield sold for Arduino that carries L293D quadruple half-H drivers (each chip drives two DC motors or one bipolar stepper, within 600 mA per channel). This page covers the L293D chip only; the shield board itself (how many chips, which Arduino pins, servo headers, power jumper) is not covered by an official document.
Specs
| Spec | Value | Source |
|---|---|---|
| Logic supply VCC1 | 4.5 V to 7 V (5 V logic supply) | source Recommended Operating Conditions, p.4 |
| Motor supply VCC2 | VCC1 up to 36 V | source Recommended Operating Conditions, p.4 |
| Continuous output current | 600 mA per channel (L293D); peak 1.2 A for 100 us or less, non-repetitive | source Absolute Maximum Ratings, p.4 |
| Output voltage drop | High level VCC2 - 1.4 V typ (VCC2 - 1.8 V min) at 0.6 A; low level 1.2 V typ, 1.8 V max at 0.6 A | source Electrical Characteristics, p.5 |
| Logic input levels | VIH 2.3 V min; VIL 1.5 V max; inputs absolute maximum 7 V | source Recommended Operating Conditions p.4; Absolute Maximum Ratings p.4 |
| Built-in protection | Output clamp diodes for inductive transients (L293D) | source Features, p.1 |
| Enable | Drivers enabled in pairs: 1,2EN for channels 1-2 and 3,4EN for channels 3-4 (active high) | source Description p.1; Pin Functions p.3 |
| Logic supply current ICC1 | 13 mA typ / 22 mA max (outputs high); 35 mA typ / 60 mA max (outputs low); 8 mA typ / 24 mA max (outputs off), IO = 0 | source Electrical Characteristics, p.5 |
| Operating temperature | 0 C to 70 C | source Recommended Operating Conditions, p.4 |
| Thermal resistance and heat limit | RthetaJA 36.4 C/W (16-pin PDIP); Figure 1 shows the free-air power limit is about 1.6 W near room temperature (read from the graph) and falls to zero at 150 C; derate or add a heat sink | source Thermal Information p.4; Figure 1, p.5 |
Power
| Value | Source | |
|---|---|---|
| Supply | VCC1 4.5-7 V (logic); VCC2 up to 36 V (motors) | source Electrical Characteristics, p.5 |
| Current | ICC1 13-35 mA typ and ICC2 2-14 mA typ with no load (IO = 0); load current comes on top | source Electrical Characteristics, p.5 |
Chip pins
These are the pins of the chip on the module, from the chip datasheet. The module's own header may label or expose them differently.
The 16-pin list above is the bare L293D. The module board is not covered by an official document. Which Arduino pins the shield uses to drive the chips is not covered here.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| 1,2EN (pin 1) | Enable for drivers 1 and 2 | active high | source Pin Functions, p.3 | |
| 1A / 2A / 3A / 4A (pins 2, 7, 10, 15) | Driver inputs, non-inverting | VIH 2.3 V min | source Pin Functions, p.3 | |
| 1Y / 2Y / 3Y / 4Y (pins 3, 6, 11, 14) | Driver outputs | Motor or load terminals | source Pin Functions, p.3 | |
| GROUND (pins 4, 5, 12, 13) | Device ground and heat-sink pins | Connect to the board ground plane | source Pin Functions, p.3 | |
| VCC2 (pin 8) | Motor (output) supply | up to 36 V | source Pin Functions, p.3 | |
| 3,4EN (pin 9) | Enable for drivers 3 and 4 | active high | source Pin Functions, p.3 | |
| VCC1 (pin 16) | 5 V supply for internal logic | 4.5-7 V | source Pin Functions, p.3 |
Build with it
Project ideas for the L293D motor driver shield. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- Two-wheel robot base: Each L293D channel is rated 600 mA continuous and drops about 2.6 V at that current, so four AA cells (about 6 V) leave roughly 3.4 V at a motor at the limit. The stocked gear motor's stall current is not sourced here, so this idea is unverified: measure it and keep it under 600 mA. Power the motor side from the battery holder, not the Uno 5 V pin. Two channels each at the 0.6 A limit would dissipate about 3.1 W (derived: 2 x 1.56 W), about twice the roughly 1.6 W free-air limit for the whole chip, so run one channel at 0.6 A at most, or keep both channels well under about 0.3 A each.
- Pump on a timer: One channel can switch a small DC pump on and off if its running and stall current are below 600 mA. The stocked pump's current is not sourced here, so this idea is unverified: measure the current first. The 2.6 V drop at 0.6 A applies. The built-in clamp diodes handle the turn-off spike. Learning project: do not leave it running unattended near electronics. Power the pump from the 4 x AA holder on the shield's motor supply, not the Uno 5 V pin; about 6 V minus the 2.6 V drop leaves roughly 3.4 V at the pump at 0.6 A, so check the pump's rated voltage.
- Button-reversed motor: Direction is set by which of the two inputs of a channel is high while its enable is high. The gear motor's current is not sourced here (unverified); keep it under the 600 mA channel limit and allow for the 2.6 V drop. Power the motor from the 4 x AA holder on the shield's motor supply, not the Uno 5 V pin.
Common mistakes
- Drawing more than 600 mA continuous per channel: that is the L293D limit, and the pin table has no current-limit pin, so a stalled motor can overheat it. At 0.6 A a driven channel drops about 2.6 V (about 1.6 W of heat), and the free-air limit near room temperature is about 1.6 W for the whole chip (source: link, Pin Functions p.3; Electrical Characteristics p.5; Figure 1 p.5)
- Leaving the enable pins low or floating: the drivers of a pair are off unless 1,2EN or 3,4EN is high (source)
- Feeding the logic pins more than 7 V or running VCC1 outside 4.5-7 V (source)
Not covered by the official source
- Shield board not documented: chip count, Arduino pin mapping, power jumper and servo header behaviour are unknown.
- Motor and pump currents for the stocked motors are not sourced (their pages have no datasheet), so the ideas below are unverified against them; only the 600 mA channel limit and the 2.6 V drop are from the sheet. No stocked stepper motor is documented to fit 600 mA, so no stepper idea is given.
- Table values are from pages 4 and 5 of the TI PDF.
Sources
- link (TI L293, L293D, SLRS008D, Sept 1986 revised Jan 2016; maker)