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TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 1

TRINAMIC® Motion Control GmbH & Co KG

Hamburg, Germany

WWW.TRINAMIC.COM

Features

The TMC236 / TMC236A / TMC236B (1) is a dual full bridge driver IC for bipolar stepper motor control

applications. It is realized in a HVCMOS technology combined with Low-RDS-ON high efficiency

MOSFETs (pat. pend.). It allows driving a coil current of up to 1500mA even at high environment

temperatures. Its low current consumption and high efficiency together with the miniature package

make it a perfect solution for embedded motion control and for battery powered devices. The low

power dissipation makes the TMC236 an optimum choice for drives, where a high reliability is desired.

Internal DACs allow microstepping as well as smart current control. The device can be controlled by a

serial interface (SPI™

) or by analog / digital input signals. Short circuit, temperature, undervoltage and

overvoltage protection are integrated.

• Control via SPI with easy-to-use 12 bit protocol or external analog / digital signals

• Short circuit, overvoltage and over temperature protection integrated

• Status flags for overcurrent, open load, over temperature, temperature pre-warning, undervoltage

• Integrated 4 bit DACs allow up to 16 times microstepping via SPI (can be expanded to 64

microsteps)

• Any resolution via analog control

• Mixed decay feature for smooth motor operation

• Slope control user programmable to reduce electromagnetic emissions

• Chopper frequency programmable via a single capacitor or external clock

• Current control allows cool motor and driver operation

• Internal open load detector

• 7V to 34V motor supply voltage (A-type)

• Up to 1500mA output current and more than 800mA at 105°C

• 3.3V or 5V operation for digital part

• Low power dissipation via low RDS-ON power stage

• Standby and shutdown mode available

(1) The term TMC236 in this datasheet always refers to the TMC236B, TMC236A and the TMC236.

The major differences in the older TMC236 are explicitly marked with “non-A-type”. The TMC236A

brings a number of enhancements and is fully backward compatible to the TMC236. The latest

revision TMC236B is 100% compatible to the TMC236A.

TMC236/B – DATA SHEET

High current, low power dissipation microstep

stepper motor driver with protection /

diagnostics and SPI Interface

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01)   2 
Copyright © 2004, TRINAMIC Motion Control GmbH & Co KG 
 
FEATURES.............................................................................................................................................. 1 
PINNING .................................................................................................................................................. 5 
PACKAGE CODES.................................................................................................................................... 5 
PQFP44 DIMENSIONS ............................................................................................................................ 6 
APPLICATION CIRCUIT / BLOCK DIAGRAM ....................................................................................... 7 
PIN FUNCTIONS ...................................................................................................................................... 7 
LAYOUT CONSIDERATIONS ................................................................................................................ 8 
CONTROL VIA THE SPI INTERFACE ................................................................................................... 9 
SERIAL DATA WORD TRANSMITTED TO TMC236 ....................................................................................... 9 
SERIAL DATA WORD TRANSMITTED FROM TMC236 .................................................................................. 9 
TYPICAL WINDING CURRENT VALUES ..................................................................................................... 10 
BASE CURRENT CONTROL VIA INA AND INB IN SPI MODE ....................................................................... 10 
CONTROLLING THE POWER DOWN MODE VIA THE SPI INTERFACE ........................................................... 10 
OPEN LOAD DETECTION ........................................................................................................................ 11 
STANDBY AND SHUTDOWN MODE........................................................................................................... 11 
POWER SAVING .................................................................................................................................... 11 
PROTECTION FUNCTIONS ................................................................................................................. 12 
OVERCURRENT PROTECTION AND DIAGNOSIS ........................................................................................ 12 
OVERTEMPERATURE PROTECTION AND DIAGNOSIS................................................................................. 12 
OVERVOLTAGE PROTECTION AND ENN PIN BEHAVIOR ............................................................................ 12 
CHOPPER PRINCIPLE ......................................................................................................................... 13 
CHOPPER CYCLE / USING THE MIXED DECAY FEATURE............................................................................ 13 
ADAPTING THE SINE WAVE FOR SMOOTH MOTOR OPERATION .................................................................. 14 
BLANK TIME ......................................................................................................................................... 14 
BLANK TIME SETTINGS .......................................................................................................................... 14 
CLASSICAL NON-SPI CONTROL MODE (STAND ALONE MODE) .................................................. 15 
PIN FUNCTIONS IN STAND ALONE MODE.................................................................................................. 15 
INPUT SIGNALS FOR MICROSTEP CONTROL IN STAND ALONE MODE .......................................................... 15 
CALCULATION OF THE EXTERNAL COMPONENTS ....................................................................... 16 
SENSE RESISTOR ................................................................................................................................. 16 
EXAMPLES FOR SENSE RESISTOR SETTINGS .......................................................................................... 16 
HIGH SIDE OVERCURRENT DETECTION RESISTOR RSH ............................................................................ 16 
MAKING THE CIRCUIT SHORT CIRCUIT PROOF ......................................................................................... 17 
OSCILLATOR CAPACITOR ...................................................................................................................... 18 
TABLE OF OSCILLATOR FREQUENCIES.................................................................................................... 18 
PULL-UP RESISTORS ON UNUSED INPUTS ............................................................................................... 18 
POWER SUPPLY SEQUENCING CONSIDERATIONS .................................................................................... 18 
SLOPE CONTROL RESISTOR ................................................................................................................. 19 
EXAMPLE FOR SLOPE SETTINGS ............................................................................................................ 19 
ABSOLUTE MAXIMUM RATINGS ....................................................................................................... 20 
ELECTRICAL CHARACTERISTICS ..................................................................................................... 20 
OPERATIONAL RANGE .......................................................................................................................... 20 
DC CHARACTERISTICS ......................................................................................................................... 21 
AC CHARACTERISTICS ......................................................................................................................... 22 
THERMAL PROTECTION (1) ................................................................................................................... 23 
THERMAL CHARACTERISTICS ................................................................................................................ 23 
TYPICAL POWER DISSIPATION AT HIGH LOAD / HIGH TEMPERATURE ........................................................ 23 
SPI INTERFACE TIMING ...................................................................................................................... 24 

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 3

PROPAGATION TIMES ........................................................................................................................... 24

USING THE SPI INTERFACE ................................................................................................................... 24

SPI FILTER (ONLY A-TYPE) ................................................................................................................... 24

ESD PROTECTION ............................................................................................................................... 25

APPLICATION NOTE: EXTENDING THE MICROSTEP RESOLUTION ............................................. 26

DOCUMENTATION REVISION ............................................................................................................ 27

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 4

Life support policy

TRINAMIC Motion Control GmbH & Co KG does not

authorize or warrant any of its products for use in life

support systems, without the specific written consent

of TRINAMIC Motion Control GmbH & Co KG.

Life support systems are equipment intended to

support or sustain life, and whose failure to perform,

when properly used in accordance with instructions

provided, can be reasonably expected to result in

personal injury or death.

Information given in this data sheet is believed to be

accurate and reliable. However no responsibility is

assumed for the consequences of its use nor for any

infringement of patents or other rights of third

parties, which may result from its use.

Specifications subject to change without notice.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 5

Pinning

TMC 236 / 236A

QFP44

BL2

OB1

OB2

BRB

VSB

INB

AGND

SLP

INA

GND

VCC

ANN

OA1

OA2

OA1

BRA

VSA

SRA

GND

SDO

SDI

SCK

SRB

CSN

BL1

OSC

ENN

SPE

Package codes

Type

Package

Temperature range

Lead free (ROHS)

Code/marking

TMC236B

PQFP44

automotive (1)

Yes

TMC236B-PA

TMC236A

PQFP44

automotive (1)

Yes

TMC236A-PA

TMC236

PQFP44

automotive (1)

From date code 30/04

TMC236-PA

(1) ICs are not tested according to automotive standards, but are usable within the complete

automotive temperature range.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 6

PQFP44 Dimensions

REF

MIN.

MAX.

1.6

0.09

0.2

0.05

0.15

0.30

0.45

0.75

0.8

0.08

All dimensions are in mm.

L: Co-planarity of pins

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 7

Application Circuit / Block Diagram

RSH

Coil A

+VM

Coil B

100µF220nF

N N

P P

TMC236AVT

DAC

INA

INB

VREF

REFSEL

PWM-CTRL

ANNSPE

Current Controlled

Gate Drivers

Current Controlled

Gate Drivers

SLP

RSLP

PWM-CTRL

OSC

Control & Diagnosis

Parallel

Control SPI-

Interface

REFSEL

GNDAGND

Under-

voltage

Tem-

perature

OSC

VCC

1nF

100nF

+VCC

SCK

SDI

SDO

CSN

BL2BL1

[MDBN]

[PHA]

[ERR]

[PHB]

stand alone mode

[MDAN]

OA1

OA2

OB1

OB2

VSB

VSA

SRA

BRA

SRB

BRB

[...]: function in stand alone mode

ENN

VCC/2

Pin Functions

Function

Motor supply voltage

Short to GND detection comparator –

connect to VS if not used

VCC

3.0-5.5V supply voltage for analog

and logic circuits

GND

Digital / Power ground

AGND

Analog ground (Reference for SRA,

SRB, OSC, SLP, INA, INB, SLP)

OSC

Oscillator capacitor or external clock

input for chopper

INA

Analog current control phase A

INB

Analog current control input phase B

SCK

Clock input of serial interface

SDO

Data output of serial interface (tri-state)

SDI

Data input of serial interface

CSN

Chip select input of serial interface

ENN

Device enable (low active), and

overvoltage shutdown input

SPE

Enable SPI mode (high active). Tie to

GND for non-SPI applications

ANN

Enable analog current control via

INA and INB (low active)

SLP

Slope control resistor.

BL1, BL2

Digital blank time select

SRA, SRB

Bridge A/B current sense resistor input

OA1, OA2

Output of full-bridge A

OB1, OB2

Output of full-bridge B

VSA, VSB

Supply voltage for bridge A/B

BRA, BRB

Bridge A/B sense resistor

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 8

Layout Considerations

For optimal operation of the circuit a careful board layout is important, because of the combination of

high current chopper operation coupled with high accuracy threshold comparators. Please pay special

attention to a massive grounding. Depending on the required motor current, either a single massive

ground plane or a ground plane plus star connection of the power traces may be used. The schematic

shows how the high current paths can be routed separately, so that the chopper current does not flow

through the system’s GND-plane. Tie the TMC236’s AGND and GND to the GND plane. Additionally,

use enough filtering capacitors located near to the board’s power supply input and small ceramic

capacitors near to the power supply connections of the TMC236. Use low inductance sense resistors,

or add a ceramic capacitor in parallel to each resistor to avoid high voltage spikes. In some

applications it may become necessary to introduce additional RC-filtering into the VT and SRA / SRB

line, as shown in the schematic, to prevent spikes from triggering the short circuit protection or the

chopper comparator.

Be sure to connect all pins of the PQFP package for each of the double/quad output pins externally.

Each two of these output pins should be treated as if they were fused to a single wide pin (as shown in

the drawing). Each two pins are used as cooling fin for one of the eight integrated output power

transistors. Use massive motor current traces on all these pins and multiple vias, if the output trace is

changed to a different layer near the package.

A symmetrical layout on all of the OA and OB pins is required, to ensure proper heat dissipation on all

output transistors. Otherwise proper function of the thermal protection can not be guaranteed!

A multi-layer PCB shows superior thermal performance, because it allows usage of a massive GND

plane, which will act as a heat spreader. The heat will be coupled vertically from the output traces to

the GND plane, since vertical heat distribution in PCBs is quite effective. Heat dissipation can be

improved by attaching a heat sink to the package directly.

Please be aware, that long or thin traces to the sense resistors may add substantial resistance and

thus reduce output current. The same is valid for the high side shunt resistor. Use short and straight

traces to avoid parasitic inductivities, because these can generate large voltage spikes and EMV

problems.

+VM

GND

GND-

Plane

RSB

RSA

RSH

CVM

100R

optional

voltage divider

TMC236/

TMC246

100R

3.3 -

10nF

SRA

SRB

optional filter

AGND

GND

100nF

VSA

VSB

BRA

BRB

RDIV

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 9

Control via the SPI Interface

The SPI data word sets the current and polarity for both coils. By applying consecutive values,

describing a sine and a cosine wave, the motor can be driven in microsteps. Every microstep is

initiated by its own telegram. Please refer to the description of the analog mode for details on the

waveforms required. The SPI interface timing is described in the timing section. We recommend the

TMC428 to automatically generate the required telegrams and motor ramps for up to three motors.

Serial data word transmitted to TMC236

(MSB transmitted first)

Bit

Name

Function

Remark

MDA

mixed decay enable phase A

“1” = mixed decay

CA3

current bridge A.3

MSB

CA2

current bridge A.2

CA1

current bridge A.1

CA0

current bridge A.0

LSB

PHA

polarity bridge A

“0” = current flow from OA1 to OA2

MDB

mixed decay enable phase B

“1” = mixed decay

CB3

current bridge B.3

MSB

CB2

current bridge B.2

CB1

current bridge B.1

CB0

current bridge B.0

LSB

PHB

polarity bridge B

“0” = current flow from OB1 to OB2

Serial data word transmitted from TMC236

(MSB transmitted first)

Bit

Name

Function

Remark

always “0”

always “1”

overtemperature

“1” = chip off due to overtemperature

OTPW

temperature prewarning

“1” = prewarning temperature exceeded

driver undervoltage

“1” = undervoltage on VS

OCHS

overcurrent high side

3 PWM cycles with overcurrent within 63 PWM cycles

OLB

open load bridge B

no PWM switch off for 14 oscillator cycles

OLA

open load bridge A

no PWM switch off for 14 oscillator cycles

OCB

overcurrent bridge B low side

3 PWM cycles with overcurrent within 63 PWM cycles

OCA

overcurrent bridge A low side

3 PWM cycles with overcurrent within 63 PWM cycles

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 10

Typical winding current values

Current setting

CA3..0 / CB3..0

Percentage of

current

Typical trip voltage of the current sense comparator

(internal reference or analog input voltage of 2V is used)

0000

0 V (bridge continuously in slow decay condition)

0001

6.7%

23 mV

0010

13.3%

45 mV

...

1110

93.3%

317 mV

1111

100%

340 mV

The current values correspond to a standard 4 Bit DAC, where 100%=15/16. The contents of all

registers is cleared to “0” on power-on reset or disable via the ENN pin, bringing the chip to a low

power standby mode. All SPI inputs have Schmitt-Trigger function.

Base current control via INA and INB in SPI mode

In SPI mode, the IC can use an external reference voltage for each DAC. This allows the adaptation to

different motors. This mode is enabled by tying pin ANN to GND. A 2.0V input voltage gives full scale

current of 100%. In this case, the typical trip voltage of the current sense comparator is determined by

the input voltage and the DAC current setting (see table above) as follows:

VTRIP,A = 0.17 VINA  “percentage SPI current setting A”

VTRIP,B = 0.17 VINB  “percentage SPI current setting B”

A maximum of 3.0V VIN is possible. Multiply the percentage of base current setting and the DAC table

to get the overall coil current. It is advised to operate at a high base current setting, to reduce the

effects of noise voltages. This feature allows a high resolution setting of the required motor current

using an external DAC or PWM-DAC (see schematic for examples).

47K

100nF

AGND

INA

INB

ANN

µC-

PWM

using PWM signal

100KµC-

Port .2

8 level via R2R-DAC

51K

100K

µC-

Port .1

µC-

Port .0

2 level control

µC-

Port

+VCC

10nF

Controlling the power down mode via the SPI interface

Standard

function

MxA

CA3

CA2

PhA

- 0 -

Control

word

function - -

Bit

Enable standby mode and

clear error flags

CA1

CA0

MxB

CB3

CB2

PhB

CB1

CB0

000 0 00 0

Programming current value “0000” for both coils at a time clears the overcurrent flags and switches the

TMC236 into a low current standby mode with coils switched off.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 11

Open load detection

Open load is signaled, whenever there are more than 14 oscillator cycles without PWM switch off. Note

that open load detection is not possible while coil current is set to “0000”, because the chopper is off in

this condition. The open load flag will then always be read as inactive (“0”). During overcurrent and

undervoltage or over temperature conditions, the open load flags also become active!

Due to their principle, the open load flags not only signal an open load condition, but also a torque loss

of the motor, especially at high motor velocities. To detect only an interruption of the connection to the

motor, it is advised to evaluate the flags during stand still or during low velocities only (e.g. for the first

or last steps of a movement).

Standby and shutdown mode

The circuit can be put into a low power standby mode by the user, or, automatically goes to standby on

Vcc undervoltage conditions. Before entering standby mode, the TMC236 switches off all power driver

outputs. In standby mode the oscillator becomes disabled and the oscillator pin is held at a low state.

The standby mode is available via the interface in SPI-mode and via the ENN pin in non-SPI mode.

The shutdown mode even reduces supply current further. It can only be entered in SPI-mode by pulling

the ENN pin high. In shutdown additionally all internal reference voltages become switched off and the

SPI circuit is held in reset.

Power saving

The possibility to control the output current can dramatically save energy, reduce heat generation and

increase precision by reducing thermal stress on the motor and attached mechanical components. Just

reduce motor current during stand still: Even a slight reduction of the coil currents to 70% of the current

of the last step of the movement, halves power consumption! In typical applications a 50% current

reduction during stand still is reasonable.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 12

Protection Functions

Overcurrent protection and diagnosis

The TMC236 uses the current sense resistors on the low side to detect an overcurrent: Whenever a

voltage above 0.61V is detected, the PWM cycle is terminated at once and all transistors of the bridge

are switched off for the rest of the PWM cycle. The error counter is increased by one. If the error

counter reaches 3, the bridge remains switched off for 63 PWM cycles and the error flag is read as

“active”. The user can clear the error condition in advance by clearing the error flag. The error counter

is cleared, whenever there are more than 63 PWM cycles without overcurrent. There is one error

counter for each of the low side bridges, and one for the high side. The overcurrent detection is

inactive during the blank pulse time for each bridge (resp. the corresponding bridge in non-A-type), to

suppress spikes which can occur during switching.

The high side comparator detects a short to GND or an overcurrent, whenever the voltage between VS

and VT becomes higher than 0.15 V at any time, except for the blank time period which is logically

ORed for both bridges. Here all transistors become switched off for the rest of the PWM cycle,

because the bridge with the failure is unknown.

The overcurrent flags can be cleared by disabling and re-enabling the chip either via the ENN pin or by

sending a telegram with both current control words set to “0000”. In high side overcurrent conditions

the user can determine which bridge sees the overcurrent, by selectively switching on only one of the

bridges with each polarity (therefore the other bridge should remain programmed to “0000”).

Over temperature protection and diagnosis

The circuit switches off all output power transistors during an over temperature condition. The over

temperature flag should be monitored to detect this condition. The circuit resumes operation after cool

down below the temperature threshold. However, operation near the over temperature threshold

should be avoided, if a high lifetime is desired.

Overvoltage protection and ENN pin behavior

During disable conditions the circuit switches off all output power transistors and goes into a low

current shutdown mode. All register contents is cleared to “0”, and all status flags are cleared. The

circuit in this condition can also stand a higher voltage, because the voltage then is not limited by the

maximum power MOSFET voltage. The enable pin ENN provides a fixed threshold of ½ VCC (TTL level

in non-A-type) to allow a simple overvoltage protection up to 40V using an external voltage divider (see

schematic for A-type).

ENN

µC-Port (opt.)

low=Enable,

high=Disable

+VM

for switch off at 26 - 29V:

at VCC=5V: R1=100K; R2=10K

at VCC=3.3V: R1=160K; R2=10K

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 13

Chopper Principle

Chopper cycle / Using the mixed decay feature

The TMC236 uses a quiet fixed frequency chopper. Both coils are chopped with a phase shift of 180

degrees. The mixed decay option is realized as a self stabilizing system (pat. fi.), by shortening the fast

decay phase, if the ON phase becomes longer. It is advised to enable the mixed decay for each phase

during the second half of each microstepping half-wave, when the current is meant to decrease. This

leads to less motor resonance, especially at medium velocities. With low velocities or during standstill

mixed decay should be switched off. In applications requiring high resolution, or using low inductivity

motors, the mixed decay mode can also be enabled continuously, to reduce the minimum motor

current which can be achieved. When mixed decay mode is continuously on or when using high

inductivity motors at low supply voltage, it is advised to raise the chopper frequency to minimum

36kHz, because the half chopper frequency could become audible under these conditions.

RSENSE

SWC

SWOSWC

SWO

On phase:

Current flows in target

direction

RSENSE

Fast decay phase:

Current flows back into

power supply

SWC SWO

SWO

RSENSE

Slow decay phase:

Current re-circulation

SWC SWO

SWOSWC

oscillator clock

resp. external clock

actual current phase A

target current phase A

mixed decay disabled mixed decay enabled

on slow decay on

fast decay

slow decay

When polarity is changed on one bridge, the PWM cycle on that bridge becomes restarted at once.

Fast decay switches off both upper transistors, while enabling the lower transistor opposite to the

selected polarity. Slow decay always enables both lower side transistors.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 14

Adapting the sine wave for smooth motor operation

After reaching the target current in each chopper cycle, both, the slow decay and the fast decay cycle

reduce the current by some amount. Especially the fast decay cycle has a larger impact. Thus, the

medium coil current always is a bit lower than the target current. This leads to a flat line in the current

shape flowing through the motor. It can be corrected, by applying an offset to the sine shape. In mixed

decay operation via SPI, an offset of 1 does the job for most motors.

ITarget current

Coil current

ITarget current

Coil current

Coil current does not have optimum shape Target current corrected for optimum shape of coil current

Blank Time

The TMC236 uses a digital blanking pulse for the current chopper comparators. This prevents current

spikes, which can occur during switching action due to capacitive loading, from terminating the

chopper cycle. The lowest possible blanking time gives the best results for microstepping: A long blank

time leads to a long minimum turn-on time, thus giving an increased lower limit for the current. Please

remark, that the blank time should cover both, switch-off time of the lower side transistors and turn-on

time of the upper side transistors plus some time for the current to settle. Thus the complete switching

duration should never exceed 1.5µs.

The TMC236 allows adapting the blank time to the load conditions and to the selected slope in four

steps (the effective resulting blank times are about 200ns shorter in the non-A-type):

Blank time settings

BL2

BL1

Typical blank time

GND

0.6 µs

GND

VCC

0.9 µs

VCC

GND

1.2 µs

VCC

1.5 µs

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 15

Classical non-SPI control mode (stand alone mode)

The driver can be controlled by analog current control signals and digital phase signals. To enable this

mode, tie pin SPE to GND. In this mode, the SPI interface is disabled and the SPI input pins have

alternate functions. The internal DACs are forced to “1111”.

Pin functions in stand alone mode

Stand alone

mode name

Function in stand alone mode

SPE

(GND)

Tie to GND to enable stand alone mode

ANN

MDAN

Enable mixed decay for bridge A (low = enable)

SCK

MDBN

Enable mixed decay for bridge B (low = enable)

SDI

PHA

Polarity bridge A (low = current flow from output OA1 to OA2)

CSN

PHB

Polarity bridge B (low = current flow from output OB1 to OB2)

SDO

ERR

Error output (high = overcurrent on any bridge, or over temperature). In this

mode, the pin is never tri-stated.

ENN

Standby mode (high active), high causes a low power mode of the device.

Setting this pin high also resets all error conditions.

INA,

INB

INA,

INB

Current control for bridge A, resp. bridge B. Refer to AGND. The sense

resistor trip voltage is 0.34V when the input voltage is 2.0V. Maximum input

voltage is 3.0V.

Input signals for microstep control in stand alone mode

Attention: When transferring these waves to SPI operation, please remark, that the mixed decay bits

are inverted when compared to stand alone mode.

90° 180° 270° 360°

INA

INB

PHA

(SDI)

PHB

(CSN)

MDAN

(ANN)

MDBN

(SCK)

Use dotted line to improve performance

at medium velocities

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 16

Calculation of the external components

Sense Resistor

Choose an appropriate sense resistor (RS) to set the desired motor current. The maximum motor

current is reached, when the coil current setting is programmed to “1111”. This results in a current

sense trip voltage of 0.34V when the internal reference or a reference voltage of 2V is used.

When operating your motor in fullstep mode, the maximum motor current is as specified by the

manufacturer. When operating in sine step mode, multiply this value by 1.41 for the maximum current

(Imax).

RS = VTRIP / Imax

In a typical application:

RS = 0.34V / Imax

RS: Current sense resistor of bridge A, B

VTRIP: Programmed trip voltage of the current sense comparators

Imax: Desired maximum coil current

Examples for sense resistor settings

Imax

0.47

723mA

0.43

790mA

0.39

870mA

0.33

1030mA

0.27

1259mA

0.22

1545mA

High side overcurrent detection resistor RSH

The TMC236 detects an overcurrent to ground, when the voltage between VS and VT exceeds 150mV.

The high side overcurrent detection resistor should be chosen in a way that 100mV voltage drop are

not exceeded between VS and VT, when both coils draw the maximum current. In a sinestep

application, this is when sine and cosine wave have their highest sum, i.e. at 45 degrees,

corresponding to 1.41 times the maximum current setting for one coil. In a fullstep application this is

the double coil current.

In a microstep application:

RSH = 0.1V / (1.41  Imax)

In a fullstep application:

RSH = 0.1V / (2  Imax)

RSH: High side overcurrent detection resistor

Imax: Maximum coil current

However, if the user desires to use higher resistance values, a voltage divider in the range of 10 to

100 can be used for VT. This might also be desired to limit the peak short to GND current, as

described in the following chapter.

Attention: A careful PCB layout is required for the sense resistor traces and for the RSH traces.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 17

Making the circuit short circuit proof

In practical applications, a short circuit does not describe a static condition, but can be of very different

nature. It typically involves inductive, resistive and capacitive components. Worst events are

unclamped switching events, because huge voltages can build up in inductive components and result

in a high energy spark going into the driver, which can destroy the power transistors. The same is true

when disconnecting a motor during operation: Never disconnect the motor during operation!

There is no absolute protection against random short circuit conditions, but pre-cautions can be taken

to improve robustness of the circuit:

In a short condition, the current can become very high before it is interrupted by the short detection,

due to the blanking during switching and internal delays. The high-side transistors allows up to 10A

flowing for the selected blank time. The lower the external inductivity, the faster the current climbs. If

inductive components are involved in the short, the same current will shoot through the low-side

resistor and cause a high negative voltage spike at the sense resistor. Both, the high current and the

voltage spikes are a danger for the driver.

Thus there are a two things to be done, if short circuits are expected:

1. Protect SRA/SRB inputs using a series resistance

2. Increase RSH to limit maximum transistor current: Use same value as for sense resistors

3. Use as short as possible blank time

The second measure effectively limits short circuit current, because the upper driver transistor with its

fixed ON gate voltage of 7V forms a constant current source together with its internal resistance and

RSH. A positive side effect is, that only one type of low ohmic resistor is required. The drawback is, that

power dissipation increases. A high side short detection resistor of 0.33 Ohms limits maximum high

side transistor current to typically 4A. The schematic shows the modifications to be done.

However, the effectiveness of these measures should be tested in the given application.

+VM

GND

RSB

RSA

RSH

CVM

100R

SRA

SRB

GND

100nF RDIV

internal

RDIV values for reference

Microstep: 27R

Fullstep: 18R

INA/INB

up to3V

18R

12R

RSH=RSA=RSB

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 18

Oscillator Capacitor

The PWM oscillator frequency can be set by an external capacitor. The internal oscillator uses a 28k

resistor to charge / discharge the external capacitor to a trip voltage of 2/3 Vcc respectively 1/3 Vcc. It

can be overdriven using an external CMOS level square wave signal. Do not set the frequency higher

than 100kHz and do not leave the OSC terminal open! The two bridges are chopped with a phase shift

of 180 degrees at the positive and at the negative edge of the clock signal.

[nF] C s40 1

f OSC

OSC 





fOSC: PWM oscillator frequency

COSC: Oscillator capacitor in nF

Table of oscillator frequencies

fOSC typ.

COSC

16.7kHz

1.5nF

20.8kHz

1.2nF

25.0kHz

1.0nF

30.5kHz

820pF

36.8kHz

680pF

44.6kHz

560pF

Please remark that an unnecessary high frequency leads to high switching losses in the power

transistors and in the motor. For most applications a chopper frequency slightly above audible range is

sufficient. When audible noise occurs in an application, especially with mixed decay continuously

enabled, the chopper frequency should be two times the audible range. For most applications we

recommend a frequency of 36.8kHz.

Pull-up resistors on unused inputs

The digital inputs all have integrated pull-up resistors, except for the ENN input, which is in fact an

analog input. Thus, there are no external pull-up resistors required for unused digital inputs which are

meant to be positive.

Power supply sequencing considerations

Upon power up, the driver initializes and switches off the bridge power transistors. However, in order

for the internal startup logic to work properly, the Vcc supply voltage has to be at least 1.0V,

respectively, the Vs supply voltage has to be at least 5.0V. When Vs goes up with Vcc at 0V, a medium

current temporary cross conduction of the power stage can result at supply voltages between 2.4V and

4.8V. While this does no harm to the driver, it may hinder the power supply from coming up properly,

depending on the power supply start up behavior.

In order to prevent this from occurring, either use a dual voltage power supply, or use a local regulator,

generating the 5V or 3.3V Vcc voltage.

Please pay attention to the local regulator start up voltage: Some newer switching regulators do not

start, before the input voltage has reached 5V. Therefore it is recommended to use a standard linear

regulator like 7805 or LM317 series or a low drop regulator or a switching regulator like the LM2595,

starting at relatively low input voltages.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 19

Slope Control Resistor

The output-voltage slope of the full bridge outputs can be controlled to reduce noise on the power

supply and on the motor lines and thus electromagnetic emission of the circuit. It is controlled by an

external resistor at the SLP pin.

Operational range:

0k  RSLP  100k

The SLP-pin can directly be connected to AGND for the fastest output-voltage slope (respectively

maximum output current). In most applications a minimum external resistance of 10 K is

recommended to avoid unnecessary high switching spikes.

Only for non-A-types the slope on the lower transistors is fixed (corresponding to a 5K to 10K slope

control resistor). For applications where electromagnetic emission is very critical, it might be necessary

to add additional LC (or capacitor only) filtering on the motor connections.

For these applications emission is lower, if only slow decay operation is used.

Please remark, that there is a tradeoff between reduced electromagnetic emissions (slow slope) and

high efficiency because of low dynamic losses (fast slope).

The following table and graph depict typical behavior measured from 15% of output voltage to 85% of

output voltage. However, the actual values measured in an application depend on multiple parameters

and may stray in a user application.

Example for slope settings

tSLP typ.

RSLP

30ns

2.2K

60ns

10K

110ns

22K

245ns

51K

460ns

100K

100

tSLP [ns] @ 10V

RSLP in KOhm

10520 20 50 100

tSLP [ns] @ 24V

200

500

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 20

Absolute Maximum Ratings

The maximum ratings may not be exceeded under any circumstances.

Symbol

Parameter

Min

Max

Unit

Supply voltage (A-type/B-type)

-0.3

Supply voltage (non-A/B-type)

-0.3

VMD

Supply and bridge voltage max. 20000s

(non-A-type: device disabled)

VTR

Power transistor voltage VOA-VBRA, VOB-

VBRB, VSA-VOA, VSB-VOB (A/B-type)

VTR

Power transistor voltage VOA-VBRA, VOB-

VBRB, VSA-VOA, VSB-VOB (non-A/B-type)

VCC

Logic supply voltage

-0.5

6.0

IOP

Output peak current (10µs pulse)

+/-7

IOC

Output current

(continuous, per bridge)

TA  85°C

1500

TA  105°C

1000

TA  125°C

800

Logic input voltage

-0.3

VCC+0.3V

VIA

Analog input voltage

-0.3

VCC+0.3V

IIO

Maximum current to / from digital pins

and analog inputs

+/-10

VVT

Short-to-ground detector input voltage

VS-1V

VS+0.3V

Junction temperature

-40

150 (1)

°C

TSTG

Storage temperature

-55

150

°C

(1) Internally limited

Electrical Characteristics

Operational Range

Symbol

Parameter

Min

Max

Unit

TAI

Ambient temperature industrial (1)

-25

125

°C

TAA

Ambient temperature automotive

-40

125

°C

Junction temperature

-40

140

°C

Bridge supply voltage (A-type/B-type)

Bridge supply voltage (non-A/B-type)

28.5

VCC

Logic supply voltage

3.0

5.5

fCLK

Chopper clock frequency

kHz

RSLP

Slope control resistor

110

K

(1) The circuit can be operated up to 140°C, but output power derates.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 21

DC Characteristics

DC characteristics contain the spread of values guaranteed within the specified supply voltage and

temperature range unless otherwise specified. Typical characteristics represent the average value of

all parts.

Logic supply voltage: VCC = 3.0 V ... 5.5 V, Junction temperature: TJ = -40°C … 150°C,

Bridge supply voltage : VS = 7 V … 34 V

(unless otherwise specified)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

ROUT,Sink

RDSON of sink-FET (A-type)

TJ = 25°C

VS  8V

0.12

0.19



OUT,Source

RDSON of source-FET (A-type)

0.22

0.36



ROUT,Sink

RDSON of sink-FET max. (A-type)

TJ =150°C

VS  8V

0.20

0.26



OUT,Source

RDSON of source-FET max.

(A-Type)

0.37

0.47



ROUT,Sink

RDSON of sink-FET (B-type)

TJ = 25°C

VS  8V

0.10

0.14



OUT,Source

RDSON of source-FET (B-type)

0.17

0.23



ROUT,Sink

RDSON of sink-FET max. (B-type)

TJ =150°C

VS  8V

0.16

0.23



OUT,Source

RDSON of source-FET max.

(B-Type)

0.28

0.38



DIO

Diode forward voltages of Oxx

MOSFET diodes (A-Type)

TJ = 25°C

IOXX = 1.05A

0.84

1.21

DIO

Diode forward voltages of Oxx

MOSFET diodes (B-Type)

TJ = 25°C

IOXX = 1.05A

0.77

1.2

VCCUV

VCC undervoltage

2.5

2.7

2.9

VCCOK

VCC voltage o.k.

2.7

2.9

3.0

ICC

VCC supply current

fosc = 25 kHz

0.75

1.20

ICCSTB

VCC supply current standby

0.45

0.75

ICCSD

VCC supply current shutdown

ENN = 1

µA

VSUV

VS undervoltage

5.5

5.9

6.2

VCCOK

VS voltage o.k.

6.1

6.4

6.7

ISSM

VS supply current with fastest

slope setting (static state)

VS = 14V

ISSD

VS supply current shutdown or

standby

VS = 14V

µA

VIH

High input voltage

(all digital inputs except ENN in A-type)

2.2

VCC +

0.3 V

VIL

Low input voltage

(all digital inputs except ENN in A-type)

-0.3

0.7

VIHYS

Input voltage hysteresis

(all digital inputs except ENN in A-type)

100

300

500

VOH

High output voltage

(output SDO)

-IOH = 1mA

VCC –

0.6

VCC –

0.2

VCC

VOL

Low output voltage

(output SDO)

IOL = 1mA

0.1

0.4

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 22

-IISL

Low input current

(SDI, SCK, CSN, BL1, BL2, SPE, ANN,

ENN for non-A-type)

VI = 0

VCC = 3.3V

VCC = 5.0V

µA

VENNH

High input voltage threshold

(input ENN) only for A/B-type

1/2 VCC

VEHYS

Input voltage hysteresis

(input ENN) only for A/B-type

0.1

VENNH

VOSCH

High input voltage threshold

(input OSC)

tbd

2/3 VCC

tbd

VOSCL

Low input voltage threshold

(input OSC)

tbd

1/3 VCC

tbd

VVTD

VT threshold voltage

(referenced to VS)

-130

-155

-180

VTRIP

SRA / SRB voltage at

DAC=”1111”

internal ref. or

2V at INA / INB

315

350

385

VSRS

SRA / SRB overcurrent detection

threshold

570

615

660

VSROFFS

SRA / SRB comparator offset

voltage

-10

RINAB

INA / INB input resistance

Vin  3 V

175

264

300

k

AC Characteristics

AC characteristics contain the spread of values guaranteed within the specified supply voltage and

temperature range unless otherwise specified. Typical characteristics represent the average value of

all parts.

Logic supply voltage: VCC = 5.0V, Bridge supply voltage: VS = 14.0V,

Ambient temperature: TA = 27°C

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

fOSC

Oscillator frequency

using internal oscillator

COSC = 1nF

1%

kHz

tRS, tFS

Rise and fall time of outputs Oxx

with RSLP=0

Vo 15% to 85%

IOXX = 800mA

tRS, tFS

Rise and fall time of outputs Oxx

with RSLP = 25K

Vo 15% to 85%

IOXX = 800mA

125

tRS, tFS

Rise and fall time of outputs Oxx

with RSLP = 50K

Vo 15% to 85%

IOXX = 800mA

250

TBL

Blank time

BL1, BL2 = VCC

1.35

1.5

1.65

µs

TONMIN

Minimum PWM on-time

BL1, BL2 =

GND

0.7

µs

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 23

Thermal Protection (1)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

TJOT

Thermal shutdown

145

155

165

°C

TJOTHYS

TJOT hysteresis

°C

TJWT

Prewarning temperature

135

145

155

°C

TJWTHYS

TJWT hysteresis

°C

(1) All temperatures are for A-type/B-type. The non-A/B-types have 5°C lower values in all fields.

Thermal Characteristics

Symbol

Parameter

Conditions

Typ

Unit

RTHA12

Thermal resistance bridge transistor junction to

ambient, one bridge chopping, fixed polarity

soldered to 2 layer

PCB

°K/W

RTHA22

Thermal resistance bridge transistor junction to

ambient, two bridges chopping, fixed polarity

soldered to 2 layer

PCB

°K/W

RTHA14

Thermal resistance bridge transistor junction to

ambient, one bridge chopping, fixed polarity

soldered to 4 layer

PCB (pessimistic)

°K/W

RTHA24

Thermal resistance bridge transistor junction to

ambient, two bridges chopping, fixed polarity

soldered to 4 layer

PCB (pessimistic)

°K/W

Typical Power Dissipation at high load / high temperature

Coil: LW = 10mH, RW = 5.0

Chopping with: tDUTY = 33% ON, only slow decay

Current

both brid-

ges on

Current

one bridge

Ambient

temperature

Motor supply

voltage

Slope

tSLP

Chopper

frequency

fCHOP

Typ total power

dissipation

560 mA

105 °C

16 V

400 ns

25 KHz

490 mW

800 mA

105 °C

16 V

400 ns

25 KHz

450 mW

560 mA

125 °C

14 V

60ns

20 KHz

350 mW

800 mA

125 °C

14 V

60ns

20 KHz

340 mW

1000 mA

70 °C

28 V

60ns

25 KHz

1000 mW

1500 mA

70 °C

28 V

60ns

25 KHz

1100 mW

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 24

SPI Interface Timing

Propagation Times

(3.0 V  VCC  5.5 V, -40°C  Tj  150°C; VIH = 2.8V, VIL = 0.5V; tr, tf = 10ns; CL = 50pF,

unless otherwise specified)

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

fSCK

SCK frequency

ENN = 0

MHz

SCK stable before and after CSN

change

tCH

Width of SCK high pulse

100

tCL

Width of SCK low pulse

100

tDU

SDI setup time

tDH

SDI hold time

SDO delay time

CL = 50pF

100

tZC

CSN high to SDO high impedance

tES

ENN to SCK setup time

µs

tPD

CSN high to OA / OB output

polarity change delay

**)

tOSC + 4

µs

*) SDO is tristated whenever ENN is inactive (high) or CSN is inactive (high).

**) Whenever the PHA / PHB polarity is changed, the chopper is restarted for that phase. However, the chopper does not

switch on, when the SRA resp. SRB comparator threshold is exceeded upon the start of a chopper period.

Using the SPI interface

The SPI interface allows either cascading of multiple devices, giving a longer shift register, or working

with a separate chip select signal for each device, paralleling all other lines. Even when there is only

one device attached to a CPU, the CPU can communicate with it using a 16 bit transmission. In this

case, the upper 4 bits are dummy bits.

SPI Filter (only A-type)

To prevent spikes from changing the SPI settings, SPI data words are only accepted, if their length is

at least 12 bit.

SDO

SDI

SCK

CSN

tES

t1t1

tCL tCH

bit11 bit10 bit0

tDtZC

tDU tDH

ENN

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 25

ESD Protection

Please be aware, that the TMC236 is an ESD sensitive device due to integrated high performance

MOS transistors.

ESD sensitive device

If the ICs are manually handled before / during soldering, special precautions have to be taken to avoid

ESD voltages above 100V HBM (Human body model). For automated SMD equipment the internal

device protection is specified with 1000V CDM (charged device model), tbf.

When soldered to the application board, all inputs and outputs withstand at least 1000V HBM.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 26

Application Note: Extending the Microstep Resolution

For some applications it might be desired to have a higher microstep resolution, while keeping the

advantages of control via the serial interface. The following schematic shows a solution, which adds

two LSBs by selectively pulling up the SRA / SRB pin by a small voltage difference. Please remark, that

the lower two bits are inverted in the depicted circuit. A full scale sense voltage of 340mV is assumed.

The circuit still takes advantage of completely switching off of the coils when the internal DAC bits are

set to “0000”. This results in the following comparator trip voltages:

Current setting

(MSB first)

Trip voltage

0000xx

0 V

000111

5.8 mV

000110

11.5 mV

000101

17.3 mV

000100

23 mV

...

111101

334.2 mV

111100

340 mV

SPI bit

DAC bit

/B1

/B0

/A1

/A0

MDA

SPI bit

DAC bit

PHA

MDB

PHB

SRA

TMC236 /

TMC239

110R

4.7nF

opt.

74HC595

Q7'

/MR

/OE

SCK

SDI

SDO

CSN

+VCC

DS1D

100K

/CS

SDI

SCK

SDO

Free for

second

TMC239

47K 47K

47K

/DACA.0

/DACA.1

/DACB.0

/DACB.1

Vcc = 5V

1/2 74HC74

DQ Note: Use a 74HC4094

instead of the HC595 to get

rid of the HC74 and inverter

Please see the FAQ document for more application information.

TMC236/A/B DATA SHEET (V2.11 / 2018-Mar-01) 27

Documentation Revision

Version

Author

BD= Bernhard Dwersteg

Description

V2.05

Added power supply sequencing considerations

V2.06

Adapted style, added info on chopper cycle

V2.07

Corrected ENN timing in SPI section

V2.10

Added IC revision TMC236B with improved MOSFETs – see chapter

“Electrical Characteristics” for any differences.

V2.11

Added Package code TMC236B

SPI is a trademark of Motorola