4

APPLICATION NOTES

MSK 4304RH PIN DESCRIPTIONS

+VCC - Is the low voltage supply for the lowside driv-

ers. A 0.1 μF ceramic capacitor in parallel with a 10μF

tantalum capacitor is the recommended bypassing from

the +VCC pin to the COM pin.

+VDD - Is the low voltage supply for the input logic to

the hybrid. A 0.1 μF ceramic capacitor in parallel with

a 4.7μF tantalum capacitor is the recommended by-

passing to the COM pin.

+VB - Is the connection used to provide power to the

floating high-side bootstrap supplies in the gate drive

circuitry.

V+ - Is the high voltage positive rail connection to the

tops of the three half bridges. Proper power supply

bypassing must be connected from this pin to the COM

pin for good filtering. This bypassing must be done as

close to the hybrid as possible. +VCC, +VDD and +VB

should be present and stable whenever V+ is present.

H INA, H INB, H INC - Are active high logic inputs for

signalling the corresponding phase high-side switch to

turn on. The logic inputs are compatible with standard

LSTTL/CMOS outputs. These inputs are clamped to VDD

and COM, they must be limited to less than 10mA if

they are allowed to exceed those limits.

L INA, L INB, L INC - Are active high inputs for signal-

ling the corresponding phase low-side switch to turn

on. The logic inputs are compatible with standard

LSTTL/CMOS outputs. These inputs are clamped to VDD

and COM, they must be limited to less than 10mA if

they are allowed to exceed those limits.

AØ, BØ, CØ - Are the pins connecting the 3 phase

bridge switch outputs.

AV-, BV-, CV- - Are the connections from the bottoms

of the three half bridges. These pins get connected to

the COM pin. If current sensing is desired they may be

connected to the COM pin through a low value sense

resistor.

COM - Is the connection that all hybrid power supply

connections are returned to and bypassed to.

Radiation performance curves for TID testing have been

generated for all radiation testing performed by MS Kennedy.

These curves show performance trends throughout the TID

test process and can be located in the MSK4304RH radiation

test report. The complete radiation test report is available in

the RAD HARD PRODUCTS section on the MSK website.

TOTAL DOSE RADIATION TEST

PERFORMANCE

http://www.mskennedy.com/store.asp?pid=9951&catid=19680

UVLO - The under voltage lockout function of the MSK4304RH

prevents the device from starting before sufficient bias volt-

age is available. The UVLO feature monitors the VDD supply

and holds the outputs low until the voltage level rises above

the threshold during start up. After start up the UVLO circuit

will hold the low side switches off if VDD falls below the thresh-

old but the high side switches will not be controlled by UVLO

after start up.

MAXIMUM DUTY CYCLE AND HIGH SIDE BIAS - The

MSK4304RH uses three independent bootstrap circuits to

power each of the high side switches. When the switches are

turned on the high side drivers are powered by the charge

in the bootstrap capacitors. The voltage on the bootstrap

capacitors has an initial 1.2V drop and decays at a rate of

approximately 0.5V every 100μS. The voltage can be ap-

proximated by the equation:

trol my result.

The lowside switches must be activate every cycle or held

active during static operation to provide a return path for

charging the highside bootstrap capacitor and prevent loss

of highside control.

8548-35 Rev. J 8/14