MAX14850
Six-Channel Digital Isolator
13Maxim Integrated
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 (VCCA–VGNDA) is higher or lower voltage than
(VCCB–VGNDB), 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 resis-
tors. 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
supplies 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).
Startup and Undervoltage Lockout
The VCCA and VCCB supplies are both internally
monitored 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 external
pullup resistor on the open-drain output. The unidirectional
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 MAX14850ASE+ 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.
MAX14850AEE+ has not been submitted for certification.
Table 2. Safety Regulatory Approvals (Pending) (MAX14850ASE+)
Table 1. Output Behavior During Undervoltage Conditions
VIN VCCA VCCB VOUTA_ VOUTB_
1 Powered Powered 1 1
0 Powered Powered 0 0
XUnder Voltage Powered Follows VCCA 1
X Powered Under Voltage 1Follows VCCB
SAFETY AGENCY STANDARD ISOLATION NUMBER FILE NUMBER
UL UL1577 Recognized 600VRMS isolation voltage for 60 seconds E351759
VDE Approved to 60747-17 Basic insulation, 600VRMS for 60 seconds Pending