MAX14850 Datasheet, PDF(12/16 Page) Maxim Integrated Products

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MAX14850

Six-Channel Digital Isolator

Ground Isolation/Level Shifting

The MAX14850 tolerates a ground difference of 600VRMS.

Therefore, VGNDA can be 850VDC higher or lower than

VGNDB. In addition, the device translates logic levels

when (VCCAâVGNDA) is higher or lower voltage than

(VCCBâVGNDB), as long as each is within the valid 3.0V

to 5.5V range.

Unidirectional and Bidirectional Channels

The MAX14850 operates both as a unidirectional device

and bidirectional device simultaneously. Each unidirec-

tional channel can only be used in the direction shown in

the functional diagram. The bidirectional channels func-

tion without requiring a direction control input.

Unidirectional Channels

The device features four unidirectional channels that

operate independently with guaranteed data rates from

DC to 50Mbps. The output driver of each unidirectional

channel is push-pull, eliminating the need for pullup

resistors. The outputs are able to drive both TTL and

CMOS logic inputs.

Bidirectional Channels

The device features two bidirectional channels that have

open-drain outputs. The bidirectional channels do not

require a direction control input. A logic-low on one side

causes the corresponding pin on the other side to be

pulled low while avoiding data latching within the device.

The input logic-low threshold (VIT) of I/OA1 and I/OA2 are

at least 50mV lower than the output logic-low voltages of I/

OA1 and I/OA2. This prevents an output logic-low on side

A from being accepted as an input low and subsequently

transmitted to side B, thus preventing a latching action.

The I/OA1, I/OA2, I/OB1, and I/OB2 pins have open-drain

outputs, requiring pullup resistors to their respective sup-

plies for logic-high outputs. The output low voltages are

guaranteed for sink currents of up to 30mA for side B, and

10mA for side A (see the Electrical Characteristics table).

The bidirectional channels of the device support I2C

clock stretching.

Startup and Undervoltage Lockout

The VCCA and VCCB supplies are both internally moni-

tored for undervoltage conditions. Undervoltage events

can occur during power-up, power-down, or during

normal operation due to a slump in the supplies. When an

undervoltage event is detected on either of the supplies, all

outputs on both sides are automatically controlled, regard-

less of the status of the inputs. The bidirectional outputs

become high impedance and are pulled high by the exter-

nal pullup resistor on the open-drain output. The unidirec-

tional outputs are pulled high internally to the voltage of the

VCCA or VCCB supply during undervoltage conditions.

When an undervoltage condition is detected on either

supply, all unidirectional outputs are pulled to the supplies

(Table 1). The bidirectional outputs are high impedance

and pulled to the supplies by the external pullup resistors.

Safety Regulatory Approvals

The MAX14850 is safety certified by UL, CSA, and

IEC 60747-5-2. Per UL1577, the MAX14850 is 100%

tested at an equivalent VISO of 720VRMS for one second

(see Table 2).

Figure 3 shows the behavior of the outputs during power-

up and power-down.

Table 1. Output Behavior During Undervoltage Conditions

VIN

VCCA

VCCB

VOUTA_

Powered

Under Voltage

Powered

Follows VCCA

Powered

Under Voltage

VOUTB_

Follows VCCB

Table 2. Safety Regulatory Approvals (Pending)

SAFETY AGENCY

VDE

STANDARD

UL1577 Recognized

Approved to 60747-17

ISOLATION NUMBER

600VRMS isolation voltage for 60 seconds

Basic insulation, 600VRMS for 60 seconds

FILE NUMBER

Pending

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