High Performance Driver/Comparator,

Active Load on a Single Chip

AD53509

Rev. B

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FEATURES

250 MHz operation

Driver/comparator and active load included

On-chip Schottky diode bridge

52-lead LQFP_EP package

APPLICATIONS

Automatic test equipment (ATE)

Semiconductor test systems

Board test systems

Instrumentation and characterization equipment

GENERAL DESCRIPTION

The AD53509 is a single chip that performs the pin electronics

functions of driver, comparator, and active load in ATE VLSI

and memory testers. In addition, a Schottky diode bridge for

the active load and a VCOM buffer are included internally.

The driver is a proprietary design that features three active

states: data high mode, data low mode, and term mode as well

as an inhibit state. The output voltage range is −2 V to +7 V to

accommodate a wide variety of test devices. The output leakage

is typically <250 nA over the signal range.

The dual comparator, with an input range equal to the driver

output range, features built-in latches and ECL-compatible

outputs. The outputs are capable of driving 50 Ω signal lines

terminated to −2 V. Signal tracking capability is >5 V/ns.

The active load can be set up to 40 mA load current with less

the buffered VCOM are independently adjustable. On-board

Schottky diodes provide high speed switching and low

capacitance.

Also included on the chip is an on-board temperature sensor

whose purpose is to give an indication of the surface temperature

or flag an alarm if proper cooling is lost. Output from the sensor

is a current sink that is proportional to absolute temperature.

The gain is trimmed to a nominal value of 1.0 μA/K. For example,

the output current can be sensed by using a 10 kΩ resistor

connected from 10 V to the THERM pin. A voltage drop across

the resistor then develops that equals

10 K × 1 μA/K = 10 mV/K = 2.98 V (at room temperature)

FUNCTIONAL BLOCK DIAGRAM

DRIVER

COMPARATOR

46Ω

V/I

V/I

ACTIVE LOAD

1.0µA/K

34

51

52

39

40

41

32

AD53509

VHDCPL

VLDCPL

39nF

CHDCPL

39nF

CLDCPL

PWRGND

VCCO

HQGND2

HQGND

VCOMS

THERM

NC

35

36

+1

31

50

49

42

43

38

37

45

47

DATA

DATA

IOD

IOD

RLD

RLD

HCOMP

LEH

LEH

QH

QH

QL

QL

LEL

LEL

LCOMP

VCOMI

IOLC

IOLRTN

IOHRTN

INHL

INHL

IOHC

NC = NO CONNECT

OUT_L

14

NC

26

2

5

8

9 33 44 46 48

Figure 1.