UM1693 datasheet(14/196 Pages) STMICROELECTRONICS

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UM1693

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voltage feedback reading is required. For dimensioning the same recommendations

apply as for R5//C2.

•

C4: it is recommended to place a ceramic capacitor on each output to dissipate energy

of high frequency, high voltage transients, in particular ESD transient pulses. A 100 V

ceramic capacitor generally has sufficient voltage capability. The device ESD

robustness of each pin is rated in Absolute Maximum Rating chapter of the datasheet

(for details refer to Chapter 11: Usage in “H-Bridge” configurations).

•

C5: C5 capacitor helps to suppress voltage transients that originate from other

actuators connected in parallel and sharing the same battery line. This capacitor will be

capable to suppress only low energetic short transient pulses. The device itself is rated

to sustain ISO 7637-2:2004(E) transient test pulses 1-4 up to test level IV according to

class C. Other methods are needed to protect the module from higher energy

transients, such as load dump.

Moreover C5 capacitor helps to suppress HF noise at the VCC pin that is generated by

the high-side driver device itself. The noise can originate from the charge pump

circuitry or from the switching slopes of PWMed outputs.

Using a 100 nF low ESR ceramic capacitor mounted close to device VCC and GND

terminals the devices meet CISPR25 Class 5 requirements measured in conducted

emission voltage method in DC, as well as in PWM, operation.

Finally, during a loss of VCC condition, the C5 capacitor supplies load current for the

demagnetization of inductive loads.

•

RSENSE: RSENSE resistor will convert the MultiSense output current, which is a copy

proportional to the load current, into a voltage which can be read by the A/D Converter

of the Microcontroller. The RSENSE should be dimensioned to ensure proper resolution

range and granularity to monitor nominal current as well as detecting open load or

overload events. Typical values of RSENSE are in the range from 1 kΩ to 2.7 kΩ, in

order to generate typically 1 V – 2 V sense voltage at nominal load current. RSENSE

selection must also take into account maximum power dissipation and maximum

current injection during reverse battery conditions and ISO 7637-2:2004(E) and ISO

7637-2:2011(E) pulse 1 transients. Refer to Section 7.2.6: Considerations on

MultiSense resistor choice for current monitorfor details on RSENSE dimensioning rules.

•

R1-R5: R1-R5 serial resistors are needed on digital inputs in order to limit the current in

the input structures as well as in the microcontroller output structures to a safe value

during transient and reverse battery conditions. A proper value for such resistors is

15 k

Ω.

No low ohmic impedance paths to GND such as pull down transistors or capacitors

shall be connected directly to the digital inputs. In such conditions, device ground shift

may trigger intrinsic parasitic structures and an unlimited, destructive current path from

VCC to the digital input will be formed.

•

RGND//DGND: a reverse polarity protection network between device ground and module

ground is needed for monolithic devices. The diode prevents unlimited destructive

current flow through the VCC - GND clamping structure in case of reverse polarity

connection. RGND paralleled to DGND avoids device ground dropping to negative

voltage during turn-off of inductive loads. Typical values range from 1 k

Ω to 4.7 kΩ,

higher values reduce power dissipation under reverse battery condition (for details

refer to Chapter 2: Reverse battery protection).

Hybrid devices (for classification of Hybrid and Monolithic HSDs please refer to

Section 5.1: Classification of M0-7 HSDs) do not need GND network (please refer to

Figure 2) in case pulses belonging to ISO 7637-2:2004(E) standard are requested to

be passed. A resistive path in the GND connection of Hybrid devices with RGND > 300,

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