Data Sheet : FLASH6 - C35

Revision B, 07.09.02

Page6of9

SYMBOL

PD

STROBE

FLASH6

DATA<5:0>

6

OVL

CLK

VIN

VREFP

VREFN

A

D

VDDA

VDD

VSSA

VSS

IBIAS

SHIELD

PINLIST

Pin

Description

Typ

Cap

VIN

Input Voltage

AIN

5pF

VREFP

Pos. Reference

Voltage

AIN

VREFN

Neg. Reference

Voltage

AIN

IBIAS

Bias Current

AIN

PD

Power down

Signal

DIN

0.1pF

CLK

Master Clock

DIN

0.1pF

DATA<5:0>

Data Output

(DATA<5>=MSB)

DOUT

OVL

Overload

DOUT

STROBE

Data Strobe Signal

DOUT

VDDA

Pos. Analog

Supply

S

VSSA

Neg. Analog

Supply

S

SHIELD

Connect to VSSA

S

VDD

Pos. Digital

Supply

S

VSS

Neg. Digital

Supply

S

THEORY OF OPERATION

The Macro Cell FLASH6 is a 6-bit single step parallel analog to

digital converter. The architecture is based on a 380 Ohm

polysilicon resistor reference ladder and static CMOS comparators.

The thermometer code of the comparator outputs is encoded in a

fast ROM encoder into straight binary code with CMOS logic signal

levels. The last comparator output is connected unlatched to the

OVL output. The area of the converter is small. The comparators do

not need auto zeroing and therefore are fast and perform minimal

kickback on the analog signal input. The conversion range is set by

the reference inputs VREFP and VREFN. The output OVL indicates

an overload condition when Vin > (VREFP - 0.5*LSB).

POWER SUPPLIES

The converter requires a single +3.3V power supply. The supplies

for analog and digital are separated and may be connected

together. However, for maximum noise immunity it is

recommended to wire them on chip to separated pins, especially

when the block is embedded in a large digital circuit. The supplies

may then be connected together on PC-board level.

The proper use of blocking capacitors in the application is important

REFERENCE VOLTAGE

Both input pads VREFP and VREFN must havea0Ohm protection

resistor. The ESD test was performed with

±1kV (Norm: MIL 883 E

method 3015).

The proper use of blocking capacitors in the application is

important !

INPUT VOLTAGE

The input pad VIN must havea0Ohm protection resistor.The ESD

test was performed with

±1kV (Norm: MIL 883 E method 3015).