GENERAL DESCRIPTION

The AD5522 is a high performance, highly integrated parametric measurement unit consisting of four independent channels. Each per-pin parametric measurement unit (PPMU) channel includes five 16-bit, voltage output DACs that set the programmable input levels for the force voltage inputs, clamp inputs, and comparator inputs (high and low). Five programmable force and measure current ranges are available, ranging from ±5 µA to ±80 mA. Four of these ranges use on-chip sense resistors; one high current range up to ±80 mA is available per channel using off-chip sense resistors. Currents in excess of ±80 mA require an external amplifier. Low capacitance DUT connections (FOHx and EXTFOHx) ensure that the device is suited to relayless test systems.The PMU functions are controlled via a simple 3-wire serial interface compatible with SPI, QSPI™, MICROWIRE™, and DSP interface standards. Interface clocks of 50 MHz allow fast updating of modes. The low voltage differential signaling (LVDS) interface protocol at 83 MHz is also supported. Comparator outputs are provided per channel for device go-no-go testing and characterization. Control registers allow the user to easily change force or measure conditions, DAC levels, and selected current ranges. The SDO (serial data output) pin allows the user to read back information for diagnostic purposes.

 

FEATURES

Quad parametric measurement unit (PMU)

FV, FI, FN (high-Z), MV, MI functions

4 programmable current ranges (internal RSENSE)

±5 μA, ±20 μA, ±200 μA, and ±2 mA

1 programmable current range up to ±80 mA (external RSENSE)

22.5 V FV range with asymmetrical operation

Integrated 16-bit DACs provide programmable levels

Gain and offset correction on chip

Low capacitance outputs suited to relayless systems

On-chip comparators per channel

FI voltage clamps and FV current clamps

Guard drive amplifier

System PMU connections

Programmable temperature shutdown

SPI- and LVDS-compatible interfaces

Compact 80-lead TQFP with exposed pad (top or bottom)

 

APPLICATIONS

Automated test equipment (ATE)

Per-pin parametric measurement unit

Continuity and leakage testing

Device power supply

Instrumentation

Source measure unit (SMU)

Precision measurement

 

THEORY OF OPERATION

The AD5522 is a highly integrated, quad per-pin parametric measurement unit (PPMU) for use in semiconductor automated test equipment. It provides programmable modes to force a pin voltage and measure the corresponding current (FVMI) and to force a pin current and measure the corresponding voltage(FIMV). The device is also capable of all other combinations,including force high-Z and measure high-Z. The PPMU can force or measure a voltage range of 22.5 V. It can force or measure currents up to ±80 mA per channel using the internal amplifier; the addition of an external amplifier enables higher current ranges. All the DAC levels required for each PMU channel are on chip.

 

FORCE AMPLIFIER

The force amplifier drives the analog output, FOHx, which drives a programmed current or voltage to the device under test (DUT). Headroom and foot room requirements for this amplifier are 3 V on either end. An additional ±1 V is dropped across the sense resistor when maximum (rated) current is flowing through it.The force amplifier is designed to drive DUT capacitances up to 10 nF, with a compensation value of 100 pF. Larger DUT capacitive loads require larger compensation capacitances.Local feedback ensures that the amplifiers are stable when disabled. A disabled channel reduces power consumption by 2.5 mA per channel.

 

CLAMPS

Current and voltage clamps are included on chip, one clamp for each PMU channel. The clamps protect the DUT in the event of an open-circuit or short-circuit condition. Internal DAC levels set the CLL (clamp low) and CLH (clamp high) levels. The clamps work to limit the force amplifier if a voltage or current at the DUT exceeds the set levels. The clamps also protect the DUT if a transient voltage or current spike occurs when changing to a different operating mode or when programming the device to a different current range.