ADC1282X

0.18

m 8-BIT 125MSPS ADC

GENERAL DESCRIPTION

The adc1282x is a CMOS Nyquit Rate 8-bit A/D converter for high performance network applications. It is a Folding,

Interpolation and Pipelined architecture.

The maximum conversion rate of adc1282x is 125MSPS and supply voltage is 3.3V single.

FEATURES

-- Resolution : 8-bit
-- Maximum Conversion Rate : 125MSPS
-- Power Supply : 3.3V Single
-- Differential Linearity

Error :

1.0 LSB

-- Integral Linearity Error :

2.0 LSB

-- Folding, Interpolation and Pipelined Scheme
-- Low Power Consumption : 165mW(Typ)
-- Operating Temperature Range : -40

C 85

TYPICAL APPLICATIONS

-- Giga-bit Ethernet Phy, magnetic recording sampling detectors, medical imagers, and digital transmission links

for telephone, cable, and terrestrial networks.

0.18

m 8-BIT 125MSPS ADC

ADC1282X

FUNCTIONAL BLOCK DIAGRAM

AINT

preamps

AINC

REFT

REFB

fold1

fold2

lsb5b

3brom

mbias

msb5b

3brom

dclogic

ckgen

CLK

MODE

AVDD33D AVSS33D AVBB33D

DO[7:0]

AVDD33A AVSS33A AVBB33A

Ver 1.2 (Apr. 2002)

This datasheet is a preliminary version. No responsibility is assumed by SEC for its use nor for any infringements of

patents or other rights of third parties that may result from its use. The content of this datasheet is subject to change

without any notice.

ADC1282X

0.18

m 8-BIT 125MSPS ADC

CORE PIN DESCRIPTION

Name

I/O Type

I/O Pad

Pin Description

AINT

phia_abb

Analog

Input

AINC

phia_abb

Analog Input -

REFT

phia_abb

Reference

Top

(2.1V)

REFB

phia_abb

Reference

Bottom(1.2V)

CLK

phicc_abb

Clock Input

phicc_abb

Power Down ( Active High )

MODE

phicc_abb

Mode (Normal Operation : Low)

DO[7]

phob8_abb

Digital Output (MSB)

DO[6:0]

phob8_abb

Digital

Output (LSB)

AVDD33A

vdd3t_abb

Analog Power (3.3V)

AVSS33A

vss3t_abb

Analog Ground

AVBB33A

vbb3_abb

Analog Sub Bias

AVDD33D

vdd3t_abb

Digital Power (3.3V)

AVSS33D

vss3t_abb

Digital Ground

AVBB33D

vbb3_abb

Digital Sub Bias

I/O Type Abbr.
-- AI: Analog Input
-- DI: Digital Input
-- AO: Analog Output
-- DO: Digital Output
-- AB: Analog Bi-direction
-- DB: Digital Bi-direction
-- AP: Analog Power
-- AG: Analog Ground
-- DP: Digital Power
-- DG: Digital Ground

ADC1282X

0.18

m 8-BIT 125MSPS ADC

ABSOLUTE MAXIMUM RATINGS

Characteristic

Symbol

Value

Unit

Supply Voltage

VADD

4.5

Analog Input Voltage

AINT,AINC

VASS to VADD

Digital Input Voltage

CLK

VASS to VADD

Digital Output Voltage

, V

VASS to VADD

Storage Temperature Range

Tstg

-55 to 125

NOTES:
1. ABSOLUTE MAXIMUM RATING specifies the values beyond which the device may be damaged permanently. Exposure

to ABSOLUTE MAXIMUM RATING conditions for extended periods may affect reliability. Each condition value is applied
with the other values kept within the following operating conditions and function operation under any of these conditions
is not implied.

2. All

voltages

are

measured

with

respect

VASS

unless

otherwise

specified.

3. 100pF

capacitor

discharged

through

1.5k

resistor

(Human

body

model)

RECOMMENDED OPERATING CONDITIONS

Characteristics

Symbol

Min

Typ

Max

Unit

Supply Voltage

AVDD33A - AVSS33A
AVDD33D - AVSS33D

3.15

3.3

3.45

Supply Voltage Difference

AVDD33A - AVDD33D

-0.1

0.0

0.1

Reference Input

Voltage(Externally)

REFT

REFB

2.1

1.2

Analog Input Voltage

VIN(AINT-AINC)

1.2

Vp-p

Operating Temperature

Topr

-40

NOTE: It is

strongly

recommended

that

all

the

supply

pins

(AVDD33A,

AVDD33D)

powered

from

the

same

source

avoid

power

latch-up.

0.18

m 8-BIT 125MSPS ADC

ADC1282X

DC ELECTRICAL CHARACTERISTICS

Characteristics

Symbol

Min

Typ

Max

Unit

Test Conditions

Resolution

Bits

Reference Current

IREF

3.5

Differential Linearity Error

DLE

±1.0

LSB

AINT : 1.35V ~ 1.95V

AINC : 1.95V ~ 1.35V

(Ramp Input)

Integral Linearity Error

ILE

±2.0

LSB

Fck : 1MHz

Bottom Offset Voltage Error

EOB

LSB

Top Offset Voltage Error

EOT

LSB

NOTES:
1.

Converter

Specifications

(unless

otherwise

specified)

AVDD33A=3.3V

AVDD33D=3.3V

AVSS33A=GND

Ta=25

TBD

Determined

AC ELECTRICAL CHARACTERISTICS

Characteristics

Symbol

Min

Typ

Max

Unit

Test Conditions

Maximum Conversion Rate

125

MSPS

source resolution

12bit

Dynamic Supply Current

Ivdd

fc=125MHz

(without system load)

Signal-to-Noise Distortion Ratio

SNDR

AINT,AINC = 5MHz

fc = 125MHz

0.18

m 8-BIT 125MSPS ADC

ADC1282X

CORE EVALUATION GUIDE

1. ADC function is evaluated by external check on the bidirectional pads connected to input nodes of HOST DSP

back-end circuit.

2. The reference voltages may be biased internally through resistor divider.

Digital

MUX

adc1282x

AINT

DO[7:0]

AINC

CLK

MODE

Power Used

: AVDD33A,AVSS33A,AVBB33A

AVDD33D,AVSS33D,AVBB33D

2.1V

1.2V

REFT

REFB

DO[7:0]

Host

DSP

Core

DO[7:0]

Bidirectional

PAD

(ADC Function Test &

externally forced Digital Input)

: 10

F Electronic Capacitor

Unless otherwise specified
: 0.1

F Ceramic Capacitor

Unless otherwise specified

ADC1282X

0.18

m 8-BIT 125MSPS ADC

PACKAGE CONFIGUATION

1 REFT

NC
REFB

AVDD33A

AVDD33A
AVBB33A
AVSS33A

AVSS33A
AINT

AINC
NC
NC

ITEST

PD
AVDD33R

AVSS33R
CLK

MODE
AVBB33R

NC
RP

AVDD33D

AVSS33D
AVSS33D

AVBB33D

DIRO[7]

DIRO[6]
DIRO[5]

DIRO[4]

DIRO[1]
DIRO[0]

DECO[7]
DECO[6]

DECO[5]

DECO[4]
DECO[3]

DECO[2]

DECO[1]
DECO[0]

CNT

10u

0.1u

DIRO[3]

DIRO[2]

3
4

5
6

8
9

10
11

13
14

15
16

18
19

21
22

23
24

46
45

44
43

41
40

39
38

36
35

34
33

31
30

28
27

26
25

10u

0.1u

10u

adc1282x

Decimation

Output

1.2V

10u

0.1u

3.3V

Normal

Output

3.3V

2.1V

3.3V

0.1u

0.18

m 8-BIT 125MSPS ADC

ADC1282X

PACKAGE PIN DESCRIPTION

Pin Name

Pin No.

I/O Type

Pin Description

REFT

Reference Top (dc 2.1V)

REFB

Reference Bottom (dc 1.2V)

AVDD33A

6,7

Analog Power (dc 3.3V)

AVBB33A

Analog Sub (dc GND)

AVSS33A

9,10

Analog Ground (dc GND)

AINT

Analog Input + (Vcom:1.65V)

AINC

Analog Input - (Vcom:1.65V)

ITEST

Test Pin

Power Down(Active High)

AVDD33R

Driver Power(dc 3.3V)

AVSS33R

Driver Ground(dc 3.3V)

CLK

Sampling Clock (125MHz)

MODE

Normal Operation : Low

AVBB33R

Driver Sub (dc GND)

CNT

Mode Control (Low:Decimation, High:Normal)

DECO[7:0]

27 34

CNT:Low, Decimation Output

DIRO[7:0]

35 42

CNT:High, Normal Output

AVBB33D

Digital Sub(dc GND)

AVSS33D

45,46

Digital Ground(dc GND)

AVDD33D

47,48

Digital Power(dc 3.3V)

ADC1282X

0.18

m 8-BIT 125MSPS ADC

PHANTOM CELL INFORMATION

-- Pins of the core can be assigned externally (Package pins) or internally (internal ports) depending on design

methods. The term "External" implies that the pins should be assigned externally like power pins.

The term "External/internal" implies that the applications of these pins depend on the user.

adc1282x

8-BIT 125MSPS ADC

REFB

REFT

AVSS18A

AVBB18A

AVDD18A

AVSS33A

AVBB33A

AVDD33A

UDF

OVF

AINT

AINC

AVDD33D

CKIN

AVBB33D

AVSS33D

DO[0]

DO[1]

DO[2]

DO3]

DO4]

DO[5]

DO[6]

DO[7]

ITEST

MODE

0.18

m 8-BIT 125MSPS ADC

ADC1282X

Pin Name

Pin Usage

Pin Layout Guide

AVDD33A

External

- Maintain the large width of lines as far as the pads.

AVSS33A

External

- place the port positions to minimize the length of power lines.

AVBB33A

External

- Do not merge the analog powers with anoter power from other

AVDD33D

External

blocks.

AVSS33D

External

- Use good power and ground source on board.

AVBB33D

External

AINT

External/Internal

- Do not overlap with digtal lines.

AINC

External/Internal

- Maintain the shotest path to pads.

CLK

External/Internal

- Separate from all other analog signals

REFT

External/Internal

- Maintain the larger width and the shorter length as far as the pads.

REFB

External/Internal

- Separate from all other digital lines.

ITEST

External/Internal

MODE

External/Internal

OVF

External/Internal

UDF

External/Internal

DO[7]

External/Internal

DO[6]

External/Internal

DO[5]

External/Internal

DO[4]

External/Internal

DO[3]

External/Internal

DO[2]

External/Internal

DO[1]

External/Internal

DO[0]

External/Internal

ADC1282X

0.18

m 8-BIT 125MSPS ADC

FEEDBACK REQUEST

It should be quite helpful to our ADC core development if you specify your system requirements on ADC in the

following characteristic checking table and fill out the additional questions.

We appreciate your interest in our products. Thank you very much.

Characteristic

Min

Typ

Max

Unit

Remarks

Analog Power Supply Voltage

Digital Power Supply Voltage

Bit Resolution

Bit

Reference Input Voltage

Analog Input Voltage

Operating Temperature

Integral Non-linearity Error

LSB

Differential Non-linearity Error

LSB

Bottom Offset Voltage Error

Top Offset Voltage Error

Maximum Conversion Rate

MSPS

Dynamic Supply Current

Power Dissipation

Signal-to-noise Ratio

Pipeline Delay

CLK

Digital Output Format

(Provide detailed description & timing diagram)

1. Between single input-output and differential input-output configurations, which one is suitable for your system

and why?

2. Please comment on the internal/external pin configurations you want our ADC to have, if you have any reason to

prefer some type of configuration.

3. Freely list those functions you want to be implemented in our ADC, if you have any.

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