DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

GENERAL DESCRIPTION

DAC1252X is a CMOS 8BIT D/A converter for general application. This digital to analog converter has a R2R
structure. Its settling time is 500ns (Typical value).

FEATURES

-- Resolution:

8-BIT

-- Differential

Linearity

Error:

1.0

LSB

-- Integral

Linearity

Error:

1.0

LSB

-- Settling

Time:

500ns

-- Low

Power

Consumption:

890

-- Power

Down

Mode

-- Operation

Temperature

Range:

-- Power

Supply:

2.5V

Single

TYPICAL APPLICATIONS

-- Hard Disk Driver (HDD)

-- Battery Operated Instruments

-- Motor Control Systems

-- General Applications

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

DAC1252X

FUNCTIONAL BLOCK DIAGRAM

D[7:0]

R2R

VRB

VRT

VOUT

AVDD25A

AVSS25A

AVDD25D

AVSS25D

AVBB25A

AMP

Ver 2.1 (Apr. 2002)

This data sheet 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 data sheet
is subject to change without any notice.

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

CORE PIN DESCRIPTION

Name

I/O Type

I/O Pad

Pin Description

D[7:0]

picc_abb

Digital Input Data (8BIT)
D[7]: MSB, D[0]: LSB

picc_abb

Power Down (Active Low)

VRT

pia_abb

Voltage Reference Top

VRB

pia_abb

Voltage Reference Bottom

VOUT

poa_abb

Analog Voltage Output

AVDD25A

vdd2t_abb

Analog Power (+2.5V)

AVSS25A

vdd2t_abb

Analog Ground (0.0V)

AVDD25D

vdd2t_abb

Digital Power (+2.5V)

AVSS25D

vss2t_abb

Digital Ground (0.0V)

AVBB25A

vbb_abb

Analog Sub Bias (0.0V)

I/O TYPE ABBR.

-- AI: Analog Input

-- DI: Digital Input

-- AO: Analog Output

-- DO: Digital Output

-- AB: Analog Bidirectional

-- DB: Digital Bidirectional

-- AP: Analog Power

-- DP: Digital Power

-- AG: Analog Ground

-- DG: Digital Ground

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

ABSOLUTE MAXIMUM RATINGS

Characteristics

Symbol

Value

Unit

Supply Voltage

VDD (AVDD25A,AVDD25D)

3.3

Analog Output Voltage

VOUT

AVSS25A to AVDD25A

Digital Input Voltage

D[7:0]

AVSS25D to AVDD25D

Reference Voltage

VRT
VRB

AVDD25A

AVSS25A

Operating Temperature Range

Topr

0 to 70

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

not implied.

2. All voltages are measured with respect to VSS(AVSS25A or AVSS25D or AVBB25A) unless otherwise specified.
3. 100pF capacitor is discharged through a 1.5k

resistor (Human body model)

RECOMMENDED OPERATING CONDITIONS

Characteristics

Symbol

Min

Typ

Max

Unit

Supply Voltage

AVDD25A - AVSS25A

AVDD25D - AVSS25D

2.375

2.5

2.625

Supply Voltage Difference

AVDD25A - AVDD25D

-0.1

0.0

0.1

Reference Voltage

VRT
VRB

0.0

-
-

2.5

Digital Input 'Low' Voltage
Digital Input 'High' Voltage

VIL

VIH

0.7

VDD

-
-

0.3

VDD

Operating Temperature

Topr

NOTE: It is strongly recommended that to avoid power latch-up all the supply pins(AVDD25A,AVDD25D) be driven from the

same source.

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

DAC1252X

DC ELECTRICAL CHARACTERISTICS

(Converter Specifications: AVDD25A=AVDD25D=2.5V, AVSS25A=AVSS25D=AVBB25A=0V,PD=High,
Top=25

C, VRT=2.5V, VRB=0.0V unless otherwise specified.)

Characteristics

Symbol

Min

Typ

Max

Unit

Conditions

Resolution

Bit

Bits

Differential Linearity Error

DLE

1.0

LSB

Integral Linearity Error

ILE

1.0

LSB

Zero Scale Error

ZSE

VRT=2.5V , VRB=0.0V

Full Scale Voltage Error

FSE

Maximum Output Voltage

MAX

2.499

MAX

VOUT(D[7:0]=High)

LSB

= Vo

MAX

/ 256

LSB Size

LSB

0.61

EOT = VRT - AIN(254,255)

NOTES:
1.

ZSE

= VOUT(D[7:0]=Low) - VRB

FSE

=VOUT(D[7:0]=High) - {(VRT-VRB)

255/256 + VRB}

AC ELECTRICAL CHARACTERISTICS

(Converter Specifications : AVDD25A=AVDD25D=2.5V, AVSS25A=AVSS25D=AVBB25A=0V, load cap=25pF
Top=25

C, PD=High, VRT=2.45V, VRB=0.05V unless otherwise specified.)

Characteristics

Symbol

Min

Typ

Max

Unit

Conditions

Supply Current

Ivdd1

0.89

Ivdd1 = I

VDD28AA0

+ I

AVDD25D

VRT=2.5V, VRB = 0.0V
Data Input: All Low or All High

Supply Current

Ivdd2

1.22

Ivdd2 = I

AVDD25A

AVDD25D

Data Input: All Low or All High

Supply Current
(Power Down Mode)

Ivdd3

Ivdd3 = I

AVDD25A

+ I

AVDD25D

Data Rate = 2MHz
Load cap = 25pF, PWDN=LOW

Short Circuit Current

VOUT: AVSS25A or AVDD25A
Data Input: All High or All Low

Analog Output Delay

Data Rate = 2MHz
Data: All LOW

All HIGH

Analog Output Rise
Time

100

Data Rate = 2MHz
Data: All LOW

All HIGH

Analog Output Fall
Time

100

Data Rate = 2MHz
Data: All HIGH

All LOW

Analog Output
Settling Time

500

Data Rate = 2MHz
Data: All LOW

All HIGH

Power Down Off Time

Ton

500

PD: HIGH

LOW

Power Down On Time

Toff

500

PD: LOW

HIGH

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

TIMING DIAGRAM

DATA

VOUT

00000000

11111111

50%

VOUT

00000000

11111111

00000000

10%

90%

DATA

VOUT

00000000

11111111

00000000

50%

± 0.5LSB

DATA

VOUT

Ton

50%

Toff

50%

± 0.5LSB

0.0V

1. Output delay measured from the 50% point of the rising edge of input data to the full scale transition.
2. Settling time measured from the 50% point of full scale transition to the output remaining within

1/2 LSB.

3. Output rise/fall time measured between the 10% and 90% points of full scale transition.

FUNCTIONAL DESCRIPTION

1. The DAC1252X has a 8BIT R-string block, two decoders, two OP amps, and control block.
2. The digital outputs of two decoders decide the voltage level of R2R block.

VRT

VRB

(

* Dn)

Rstring

n 0

3. Normal Conditions: VRT=2.45V , VRB=0.05V, PD=Low
You can change the voltages of VRT and VRB to 2.5V and 0.0V , but the performance of DAC1252X will be
degraded.

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

DAC1252X

CORE EVALUATION GUIDE

HOST

DSP

CORE

MUX

TEST PATH

AVDD25A

AVSS25A

AVDD25D

AVSS25D

AVBB25A

2.5
V

GND

2.5
V

GND

2.45

GND

0.05

GND

D[11:0]

VRT

VRB

VOUT

dac1252x

VOUT

Location

Description

F Tantalum Capacitor

0.1

F Ceramic Capacitor

TESTABILITY

Whether you use MUX or the internal logic for testability, it is required to be able to select the values of digital
inputs ( D[7:0] ).

See above figure. Only if it is, you can check the main function. (Linearity)
Normal Test Condition: VRT=2.45V, VRB=0.05V, PD=High

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

PHANTOM CELL INFORMATION

AVBB25A

[
1

]

[
2

]

[
3

]

[
4

]

[
5

]

[
6

]

[
7

]

DAC1252X

[
0

]

VRT

VRB

AVSS25A

AVDD25A

AVDD25D

AVSS25D

Pin Name

Property

Pin Usage

Pin Layout Guide

D[7:0]

Internal / External

1. Digital Input Signal lines must have same length to
reduce
propagation delay.

Internal / External

VRT

Internal / External

1. Voltage reference lines (VRT / VRB) must be wide metal
to reduce voltage drop of metal lines.
2. VOUT signal should not be crossed by any signals and
should not run next to digital signals to minimize
capacitive
coupling between the two signals.

VRB

Internal / External

VOUT

Internal / External

AVDD25A

External

1. It is recommended that you use thick analog power
metal.
When connected to PAD, the path should be kept as short
as possible.
2. Digital power and analog power are separately used.

AVSS25A

External

AVDD25D

External

AVSS25D

External

AVBB25A

External

NOTES:
1.

When the core block is connected to other blocks, it must be double guard-ring using N-well and P+ active to remove the
substrate and coupling noise. In that case, the power metal should be connected to PAD directly.

2. The Bulk power is used to reduce the influence of substrate noise.

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

DAC1252X

PACKAGE CONFIGURATION

VRB

AVDD25D

AVSS25D

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

VRB

AVBB25A

AVSS25A

AVDD25A

VOUT

VRT

0.0V

2.5V

(VSS)

(VDD)

VOUT

VRT

(2.45 V Typ.)

(0V in normal operation)

(0.05V Typ.)

D[7]

D[6]

D[5]

D[4]

D[3]

D[2]

D[1]

D[0]

DAC

1252X

Location

Description

F Tantalum Capacitor

0.1

F Ceramic Capacitor

L1~L5

Ferrite Bead ( 0.1mh )

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

PACKAGE PIN DESCRIPTION

Name

Pin No

I/O Type

Pin Description

AVDD25D

1,2

Digital Power (2.5V)

AVSS25D

3,4

Digital Ground (0.0V)

D[7:0]

10~17

Digital Input Data

VRB

23,24

Voltage Reference Bottom (0.05V)

VRT

25,26

Voltage Reference Top (2.45V)

VOUT

29,30

Analog Voltage Output

Power Down Mode (High Active)

AVDD25A

36,37

Analog Power (2.5V)

AVSS25A

38,39

Analog Ground (0.0V)

AVBB25A

47,48

Analog Sub Bias (0.0V)

5,6,7,8,9,18,19

20,21,22,27
28,32,33,34

35,40.41,42,43

44,45,46

No Connection

I/O TYPE ABBR.

-- AI: Analog Input

-- DI: Digital Input

-- AO: Analog Output

-- DO: Digital Output

-- AB: Analog Bidirectional

-- DB: Digital Bidirectional

-- AP: Analog Power

-- DP: Digital Power

-- AG: Analog Ground

-- DG: Digital Ground

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

DAC1252X

PC BOARD LAYOUT CONSIDERATION

1. PC BOARD CONSIDERATIONS

To minimize noise on the power lines and the ground lines, the digital inputs need to be shielded and decoupled.
This trace length between groups of VDD (AVDD25A,AVDD25D) and VSS (AVSS25A,AVSS25D) pins should be
as short as possible so as to minimize inductive ringing.

2. SUPPLY DECOUPLING AND PLANES

For the decoupling capacitor between the power line and the ground line, 0.1uF ceramic capacitor is used in
parallel with a 10uF tantalum capacitor.

The digital power plane(AVDD25D) and analog power plane(AVDD25A) are connected through a ferrite bead,
and also the digital ground plane(AVSS25D) and the analog ground plane(AVSS25A). This ferrite bead should be
located within 3inches of the DAC1252X. The analog power plane supplies power to the DAC1252X of the analog
output pin and related devices.

DAC1252X

0.25

µ
µ

m 2.5V 8-bit 2MSPS DAC

FEEDBACK REQUEST

We appreciate your interest in out products. If you have further questions, please specify in the attached form.

Thank you very much.

Dc / Ac Electrical Characteristic

Characteristics

Min

Typ

Max

Unit

Remarks

Supply Voltage

Power dissipation

Resolution

Bits

Analog Output Voltage

Operating Temperature

Output Load Capacitor

Output Load Resistor

Integral Non-Linearity Error

LSB

Differential Non-Linearity Error

LSB

Maximum Conversion Rate

MHz

Voltage Output DAC

Reference Voltage TOP
BOTTOM

Analog Output Voltage Range

Digital Input Format

Binary Code or 2's Complement Code

Current Output DAC

Analog Output Maximum Current

Analog Output Maximum Signal
Frequency

kHz

Reference Voltage

External Resistor for Current Setting
(RSET)

Pipeline Delay

sec

-- Do you want to Power down mode?

-- Do you want to Internal Reference Voltage (BGR)?

-- Which do you want to Serial Input TYPE or parallel Input TYPE?

-- Do you need 3.3V and 5V power supply in your system?

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