LINEAR TECHNOLOGY LTC1821 Technical data

LTC1821

www.BDTIC.com/LINEAR

16-Bit, Ultra Precise,

FEATURES

■

2µs Settling to 0.0015% for 10V Step

■

1LSB Max DNL and INL Over Industrial
Temperature Range

■

On-Chip 4-Quadrant Resistors Allow Precise 0V to
10V, 0V to –10V or ±10V Outputs

■

Low Glitch Impulse: 2nV•s

■

Low Noise: 13nV/√Hz

■

36-Lead SSOP Package

■

Power-On Reset

■

Asynchronous Clear Pin
LTC1821: Reset to Zero Scale
LTC1821-1: Reset to Midscale

U

APPLICATIO S

■

Process Control and Industrial Automation

■

Precision Instrumentation

■

Direct Digital Waveform Generation

■

Software-Controlled Gain Adjustment

■

Automatic Test Equipment

Fast Settling V

OUT

DAC

U

DESCRIPTIO

The LTC®1821 is a parallel input 16-bit multiplying voltage
output DAC that operates from analog supply voltages of
±5V up to ±15V. INL and DNL are accurate to 1LSB over the
industrial temperature range in both unipolar 0V to 10V and
bipolar ±10V modes. Precise 16-bit bipolar ±10V outputs are
achieved with on-chip 4-quadrant multiplication resistors.
The LTC1821 is available in a 36-lead SSOP package and is
specified over the industrial temperature range.

The device includes an internal deglitcher circuit that reduces
the glitch impulse to less than 2nV•s (typ). The LTC1821
settles to 1LBS in 2µs with a full-scale 10V step. The
combination of fast, precise settling and ultra low glitch make
the LTC1821 ideal for precision industrial control applica­tions.

The asynchronous CLR pin resets the LTC1821 to zero scale
and resets the LTC1821-1 to midscale.

, LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIO

16-Bit, 4-Quadrant Multiplying DAC with a

Minimum of External Components

V

REF

–V

REF

DATA

INPUTS

3 TO 6,

25 TO 36

WR

LD

CLR

16

10 9

R1

WR

24 23

3

+

LT®1468

2

–

R

COM

R1

R2

LTC1821-1

LD

CLR

7

6

15pF

8

2

V

REF

CC

DNC*

DNC*

19

18

*DO NOT CONNECT

11
R

DNC*

OFS

R

OFS

16-BIT DAC

21

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5V

0.1µF

12 14
R

R

FB

DGNDNC AGNDSAGNDF

122

FBIOUT

17 16

LTC1821/LTC1821-1

Integral Nonlinearity

1.0
V

= 10V

REF

0.8

= ±10V BIPOLAR

V

15pF

+

15

V

–

13

+

V

OUT

–

V

20

0.1µF

–15V

0.1µF

15V

V

OUT

1821 TA01

V

REF

=

–V

REF

OUT

0.6

0.4

0.2

0
–0.2
–0.4
–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8
–1.0

0

32768

16384

DIGITAL INPUT CODE

49152

65535

1821 TA02

1

LTC1821

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15
16
17
18

TOP VIEW

GW PACKAGE

36-LEAD PLASTIC SSOP WIDE

36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19

D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
WR
LD
NC
DNC*
V

–

DNC*

DGND

V

CC

D3
D2
D1
D0

CLR

REF

R

COM

R1

R

OFS

R

FB

V

OUT

I

OUT

V

+

AGNDS

AGNDF

DNC*

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WW

W

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ABSOLUTE MAXIMUM RATINGS

(Note 1)

VCC to AGNDF, AGNDS ............................... – 0.3V to 7V

VCC to DGND .............................................. –0.3V to 7V

Total Supply Voltage (V+ to V–) ............................... 36V

AGNDF, AGNDS to DGND ............................. VCC + 0.3V

DGND to AGNDF, AGNDS ............................. VCC + 0.3V

REF, R
R

OFS

Digital Inputs to DGND ............... –0.3V to (VCC + 0.3V)

I

OUT

Maximum Junction Temperature ..........................150°C

Operating Temperature Range

LTC1821C/LTC1821-1C.......................... 0°C to 70°C

LTC1821I/LTC1821-1I ....................... –40°C to 85°C

Storage Temperature Range ................ –65°C to 150°C

Lead Temperature (Soldering, 10 sec)................. 300°C

to AGNDF, AGNDS, DGND .................. ±15V

COM

, RFB, R1, to AGNDF, AGNDS, DGND ............ ±15V

to AGNDF, AGNDS............... –0.3V to (VCC + 0.3V)

U

W

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PACKAGE/ORDER INFORMATION

ORDER PART

NUMBER

LTC1821ACGW
LTC1821BCGW
LTC1821-1ACGW
LTC1821-1BCGW
LTC1821AIGW
LTC1821BIGW
LTC1821-1AIGW
LTC1821-1BIGW

T

= 125°C, θJA = 80°C/W

JMAX

*DO NOT CONNECT

Consult factory for parts specified with wider operating temperature ranges.

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = T
V+ = 15V, V– = –15V, VCC = 5V, V

SYMBOL PARAMETER CONDITIONS MIN TYP MAX MIN TYP MAX UNITS
Accuracy

Resolution ● 16 16 Bits
Monotonicity ● 16 16 Bits

INL Integral Nonlinearity TA = 25°C (Note 2) ±2 ±0.25 ±1LSB

DNL Differential Nonlinearity TA = 25°C ±1 ±0.2 ±1LSB

GE Gain Error Unipolar Mode

PSRR Power Supply Rejection Ratio VCC = 5V ±10% ● 2 0.7 2 LSB/V

2

Gain Temperature Coefficient ∆Gain/∆Temperature (Note 4) ● 1 3 1 3 ppm/°C
Unipolar Zero-Scale Error TA = 25°C ±3 ±0.25 ±2LSB

Bipolar Zero Error TA = 25°C ±12 ±2 ±8LSB

= 10V, AGNDF = AGNDS = DGND = 0V.

REF

T

to T

MIN

MAX

to T

T

MIN

MAX

= 25°C (Note 3) ±16 ±5 ±16 LSB

T

A

T

to T

MIN

MAX

Bipolar Mode
T

= 25°C (Note 3) ±16 ±2 ±16 LSB

A

to T

T

MIN

MAX

to T

T

MIN

MAX

T

to T

MIN

MAX

+

V

, V– = ±4.5V to ±16.5V ● ±2 ±0.1 ±2 LSB/V

MIN

to T

MAX

,

LTC1821B/-1B LTC1821A/-1A

● ±2 ±0.35 ±1LSB

● ±1 ±0.2 ±1LSB

● ±24 ±8 ±16 LSB

● ±24 ±5 ±16 LSB

● ±6 ±0.50 ±4LSB

● ±16 ±3 ±10 LSB

LTC1821

www.BDTIC.com/LINEAR

ELECTRICAL CHARACTERISTICS

The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are TA = T
V+ = 15V, V– = –15V, VCC = 5V, V

SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
Reference Input

R

REF

R1/R2 R1/R2 Resistance (Bipolar) (Notes 6, 11) ● 91220 kΩ
R

OFS

AC Performance (Note 4)

Analog Outputs (Note 4)

V

OUT

I

SC

SR Slew Rate RL = 2k, V+ = 15V, V– = –15V 20 V/µs

Digital Inputs

V

IH

V

IL

I

IN

C

IN

Timing Characteristics

t

DS

t

DH

t

WR

t

LD

t

CLR

t

LWD

Power Supply

I

CC

I

S

V

CC

+

V

–

V

DAC Input Resistance (Unipolar) (Note 6) ● 4.5 6 10 kΩ

, RFBFeedback and Offset Resistances (Note 6) ● 91220 kΩ

Output Voltage Settling Time ∆V
Midscale Glitch Impulse (Note 10) 2 nV•s
Digital-Feedthrough (Note 9) 2 nV•s
Multiplying Feedthrough Error V
Multiplying Bandwidth Code = Full Scale (Note 7) 600 kHz
Output Noise Voltage Density 1kHz to 100kHz (Note 7)

Output Noise Voltage 0.1Hz to 10Hz (Note 7)

1/f Noise Corner (Note 7) 30 Hz

DAC Output Swing RL = 2k, V+ = 15V, V– = –15V ● ±12.6 V

DAC Output Load Regulation V+ = 15V, V– = –15V, ±5mA Load ● 0.02 0.2 LSB/mA
Short-Circuit Current V

Digital Input High Voltage ● 2.4 V
Digital Input Low Voltage ● 0.8 V
Digital Input Current ● 0.001 ±1 µA
Digital Input Capacitance (Note 4 ) VIN = 0V ● 8pF

Data to WR Setup Time ● 60 20 ns
Data to WR Hold Time ● 0–12 ns
WR Pulse Width ● 60 25 ns
LD Pulse Width ● 110 55 ns
Clear Pulse Width ● 60 40 ns
WR to LD Delay Time ● 0ns

Supply Current, V
Supply Current, V+, V

Supply Voltage ● 4.5 5 5.5 V
Supply Voltage ● 4.5 16.5 V
Supply Voltage ● –16.5 –4.5 V

CC

= 10V, AGNDF = AGNDS = DGND = 0V.

REF

= 10V (Notes 7, 8) 2 µs

OUT

= ±10V, 10kHz Sine Wave (Note 7) 1 mV

REF

Code = Zero Scale 13 nV/√Hz
Code = Full Scale 20 nV/√Hz

Code = Zero Scale 0.45 µV
Code = Full Scale 1 µV

RL = 2k, V+ = 5V, V– = –5V ● ±2.6 V

= 0V, V+ = 15V, V– = –15V ● 12 40 mA

OUT

= 2k, V+ = 5V, V– = –5V 14 V/µs

R

L

Digital Inputs = 0V or V

–

±15V ● 4.5 7.0 mA
±5V

CC

● 1.5 10 µA

● 4.0 6.8 mA

MIN

to T

MAX

,

P-P

RMS
RMS

3

LTC1821

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ELECTRICAL CHARACTERISTICS

Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.

Note 2: ±1LSB = ±0.0015% of full scale = ±15.3ppm of full scale.
Note 3: Using internal feedback resistor.
Note 4: Guaranteed by design, not subject to test.
Note 5: I

with DAC register loaded to all 0s.

OUT

Note 6: Typical temperature coefficient is 100ppm/°C.

Note 8: To 0.0015% for a full-scale change, measured from the rising

edge of LD.
Note 9: REF

1s to all 0s. LD low and WR high.
Note 10: Midscale transition code: 0111 1111 1111 1111 to

1000 0000 0000 0000. Unipolar mode, C

Note 11: R1 and R2 are measured between R1 and R

Note 7: Measured in unipolar mode.

UW

TYPICAL PERFOR A CE CHARACTERISTICS

Midscale Glitch Impulse

40

C
V

30

20

10

0

–10

OUTPUT VOLTAGE (mV)

–20

–30

–40

0

= 30pF

FEEDBACK

= 10V

REF

1nV-s TYPICAL

0.2 0.4 0.8

TIME (µs)

0.6

WAVEFORM

500µV/DIV

1.0

1821 G01

LD PULSE

5V/DIV

GATED

SETTLING

Full-Scale Setting Waveform

V

= –10V

REF

C

FEEDBACK

0V TO 10V STEP

500ns/DIV

= 20pF

= 0V. DAC register contents changed from all 0s to all 1s or all

= 33pF.

FEEDBACK

, REF and R

COM

COM

.

Unipolar Multiplying Mode
Signal-to-(Noise + Distortion)
vs Frequency

–40

VCC = 5V

= 30pF

C

FEEDBACK

–50

1821 G02

REFERENCE = 6V

–60

–70

–80

–90

–100

SIGNAL/(NOISE + DISTORTION) (dB)

–110

10 1k 10k 100k

RMS

500kHz FILTER

80kHz FILTER

30kHz FILTER

100

FREQUENCY (Hz)

1821 G03

Bipolar Multiplying Mode
Signal-to-(Noise + Distortion)
vs Frequency, Code = All Zeros

–40

VCC = 5V USING AN LT1468

= 15pF

C

FEEDBACK

–50

REFERENCE = 6V

–60

–70

–80

–90

–100

SIGNAL/(NOISE + DISTORTION) (dB)

–110

10 1k 10k 100k

RMS

80kHz FILTER

100

FREQUENCY (Hz)

500kHz FILTER

30kHz
FILTER

1821 G04

Bipolar Multiplying Mode
Signal-to-(Noise + Distortion)
vs Frequency, Code = All Ones

–40

VCC = 5V USING AN LT1468

= 15pF

C

FEEDBACK

–50

REFERENCE = 6V

–60

–70

–80

–90

–100

SIGNAL/(NOISE + DISTORTION) (dB)

–110

10 1k 10k 100k

80kHz FILTER
30kHz FILTER

100

FREQUENCY (Hz)

4

RMS

500kHz FILTER

1821 G05

V

Supply Current vs Digital

CC

Input Voltage

5

VCC = 5V
ALL DIGITAL INPUTS
TIED TOGETHER

4

3

2

SUPPLY CURRENT (mA)

1

0

1

0

INTPUT VOLTAGE (V)

3

4

2

5

1821 G06

UW

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TYPICAL PERFOR A CE CHARACTERISTICS

Logic Threshold vs VCC Supply
Voltage

3.0

2.5

2.0

1.5

1.0

LOGIC THRESHOLD (V)

0.5

0

0

234

1

SUPPLY VOLTAGE (V)

576

1821 G07

Integral Nonlinearity (INL) Differential Nonlinearity (DNL)

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8
–1.0

0

16384

32768

DIGITAL INPUT CODE

49152

65535

1821 G08

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

DIFFERENTIAL NONLINEARITY (LSB)

–0.8
–1.0

0

16384

32768

DIGITAL INPUT CODE

LTC1821

49152

65535

1821 G09

Integral Nonlinearity vs Reference
Voltage in Unipolar Mode

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8
–1.0

–6

–10

–4

–8 8

REFERENCE VOLTAGE (V)

–2

2

0

4

Differential Nonlinearity vs
Reference Voltage in Bipolar Mode

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

DIFFERENTIAL NONLINEARITY (LSB)

–0.8
–1.0

–6

–10

–4

–8 8

REFERENCE VOLTAGE (V)

–2

2

0

4

Integral Nonlinearity vs Reference
Voltage in Bipolar Mode

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8

6

10

1821 G10

–1.0

–6

–10

–4

–8 8

–2

REFERENCE VOLTAGE (V)

2

4

6

0

10

1821 G11

Integral Nonlinearity vs VCC Supply
Voltage in Unipolar Mode

1.0

0.8

0.6
V

0.4

0.2

0
–0.2
–0.4
–0.6

INTEGRAL NONLINEARITY (LSB)

–0.8

6

1821 G13

–1.0

10

2

V

= 2.5V

REF

V

= 2.5V

REF

4

3

SUPPLY VOLTAGE (V)

= 10V

REF

V

= 10V

REF

5

7

6

1821 G14

Differential Nonlinearity vs
Reference Voltage in Unipolar Mode

1.0

0.8

0.6

0.4

0.2
0

–0.2
–0.4
–0.6

DIFFERENTIAL NONLINEARITY (LSB)

–0.8
–1.0

–6

–10

–4

–8 8

REFERENCE VOLTAGE (V)

–2

2

0

Integral Nonlinearity vs V

4

CC

Voltage in Bipolar Mode

2.0

1.5

1.0

0.5

0

V

= 10V

REF

– 0.5

–1.0

INTEGRAL NONLINEARITY (LSB)

–1.5

–2.0

2

= 2.5V

V

REF

4

3

SUPPLY VOLTAGE (V)

V

REF

V

= 2.5V

REF

5

6

6

1821 G12

Supply

= 10V

1821 G15

10

7

5