8-bit shift register for enhanced cascading with thermal shutdown

The TPIC6596 is a monolithic, high-voltage,

high-current power 8-bit shift register designed for use in systems that require

relatively high load power. The device contains a built-in voltage clamp on the

outputs for inductive transient protection. Power driver applications include

relays, solenoids, and other medium-current or high-voltage loads.

This device contains an 8-bit

serial-in, parallel-out shift register that feeds an 8-bit D-type storage register.

Data transfers through both the shift and storage registers on the rising edge of

the shift-register clock (SRCK) and the register clock (RCK) respectively. The

storage register transfers data to the output buffer when shift-register clear

(SRCLR ) is high. Write data and read data are valid only

when RCK is low. When SRCLR is low, all registers in the

device are cleared. When output enable (G) is held high, all

data in the output buffers is held low and all drain outputs are off. When

G is held low, data from the storage register is

transparent to the output buffers. The serial output (SER OUT) is clocked out of the

device on the falling edge of SRCK to provide additional hold time for cascaded

applications. This provides improved performance for applications where clock

signals can be skewed, devices are not located near one another, or the system must

tolerate electromagnetic interference.

Outputs are low-side, open-drain DMOS transistors with output ratings of 45V and

250mA continuous sink current capability. When data in the output buffers is low,

the DMOS-transistor outputs are off. When data is high, the DMOS-transistor outputs

have sink current capability.

Separate power and logic level ground

pins are provided to facilitate maximum system flexibility. Pins 1, 10, 11, and 20

are internally connected, and each pin must be externally connected to the power

system ground to minimize parasitic inductance. A single-point connection between

pin 19, logic ground (LGND), and pins 1, 10, 11, and 20, power grounds (PGND), must

be externally made in a manner that reduces crosstalk between the logic and load

circuits. The TPIC6596 is characterized for operation over the operating case

temperature range of −40°C to 125°C.