Analog Devices ADN8810 Datasheet

12-Bit High Output Current Source

FEATURES

High precision 12-bit current source
Low noise
Long term stability
Current output from 0 mA to 300 mA
Output fault indication
Low drift
Programmable maximum current
24-lead 4 mm × 4 mm leadframe chip scale package
3-wire serial interface

APPLICATIONS

Tunable laser current source
Programmable high output current source
Automatic test equipment

GENERAL DESCRIPTION

The ADN8810 is a 12-bit current source with an adjustable
full-scale output current of up to 300 mA. The full-scale out­put current is set with two external sense resistors. The output
compliance voltage is 2.5 V, even at output currents up to
300 mA.

RESET RESET

4.096V

SERIAL

INTERFACE

ADDRESS

ADN8810

FUNCTIONAL BLOCK DIAGRAM

5V 5V 3.3V

3

VREF
CS
SCLK
SDI
ADDR0-2

ENCOMP

INDICATION

DVDD AVDD PVDD

ADN8810

FAULT

SB

SB

FAULT

AVSS

Figure 1.

DVSS

IOUT

DGND

FB

R

SN

R

1.6V

R

1.6V

SN

SN

D1

03195-0-001

The device is particularly suited for tunable laser control and
can drive tunable laser front mirror, back mirror, phase, gain,
and amplification sections. A host CPU or microcontroller
controls the operation of the ADN8810 over a 3-wire SPI®
interface. The 3-bit address allows up to eight devices to be
independently controlled while attached to the same SPI bus.

The ADN8810 is guaranteed with ± 4 LSB INL and ± 0.75 LSB
DNL. Noise and digital feedthrough are kept low to ensure low
jitter operation for laser diode applications. Full-scale and
scaled output currents are given in Equations 1 and 2,
respectively.

V

10

REF

(1)

R

SN

⎛

V

Code I

REF

4096 k

R

1

SN

⎜
⎜

15

R

⎝

SN

⎞
⎟

(2)

+×××= 1.0

⎟
⎠

I×≈

FS

OUT

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] © 2004 Analog Devices, Inc. All rights reserved.

ADN8810

TABLE OF CONTENTS

ADN8810–Specifications ................................................................ 3

Serial Data Interface................................................................... 11

Timing Characteristics..................................................................... 5

Absolute Maximum Ratings............................................................ 6

ESD Caution.................................................................................. 6

Pin Configuration and Function Descriptions............................. 7

ADN8810 Terminology ................................................................... 8

Typical Performance Characteristics ............................................. 9

Functional Description.................................................................. 11

Setting Full-Scale Output Current ........................................... 11

Reference Voltage Source .......................................................... 11

Power Supplies............................................................................ 11

REVISION HISTORY

Revision 0: Initial Version

Standby and Reset Modes ......................................................... 12

Power Dissipation ...................................................................... 12

Using Multiple ADN8810s for Additional Output Current . 12

Adding Dither to the Output Current..................................... 12

Driving Common-Anode Laser Diodes ................................. 13

PC Board Layout Recommendations...................................... 13

Suggested Pad Layout for CP-24 Package ............................... 14

Outline Dimensions....................................................................... 15

Ordering Guide .......................................................................... 15

Rev. 0 | Page 2 of 16

ADN8810

ADN8810–SPECIFICATIONS

Table 1. Electrical Characteristics (AVDD = DVDD = 5 V, PVDD = 3.3 V, AVSS = DVSS = DGND = 0 V, TA= 25°C, covering IOUT
from 2% IFS to 100% IFS, unless otherwise noted.)

Parameter Symbol Condition Min Typ Max Unit

DC PERFORMANCE
Resolution N 12 Bit
Relative Accuracy INL ± 4 LSB
Differential Nonlinearity DNL ± 0.75 LSB
Offset 4 8 LSB
Offset Drift

R

= 1.6 Ω; I

SN

= 127 mA

OUT

Gain Error 1 %FS
REFERENCE INPUT
Reference Input Voltage V

3.9 4.096 4.3 V

REF

Input Current 1 µA
Bandwidth BW

2 MHz

REF

ANALOG OUTPUT
Output Current Change vs. Output

Voltage Change
Max Output Current I
Output Compliance Voltage V

∆I

/∆V

OUT

OUT

MAX

–40°C to +85°C; IFS=300 mA 2.0 2.5 V

COMP

V

= 0.7 V to 2.0 V 100 400 ppm/V

OUT

R

= 1.37 Ω

SN1

AC PERFORMANCE
Settling Time

τ

S

3 µs
Bandwidth BW 5 MHz
Current Noise Density @10 kHz iN IFS = 250 mA 7.5
I
I

= 100 mA 3

FS

= 50 mA 1.5

FS

Standby Recovery 6 µs
POWER SUPPLY1
Power Supply Voltage DVDD 3.0 5 5.5 V
AVDD 4.5 5 5.5 V
PVDD 3.0 3.3 5.5 V
Power Supply Rejection Ratio PSRR AVDD = 4.5 V to 5.5 V; * 0.4 5 µA/V
PVDD = 3.0 V to 3.6 V; * 0.4 5 µA/V

Supply Current I

I

I

I

I

DVDD

AVDD

PVDD

AVDD

PVDD

I

= 0 mA, SB = DVDD

O

I

= 0 mA, SB = DVDD

O

I

= 0 mA, SB = DVDD

O

SB

= 0 V

SB

= 0 V
FAU LT D ETEC TION
Load Open Threshold PVDD – 0.6 V
Load Short Threshold AVSS + 0.2 V
FAULT Logic Output VOH DVDD = 5.0 V 4.5 V

VOL DVDD = 5.0 V 0.5 V

LOGIC INPUTS
Input Leakage Current IIL 1 µA
Input Low Voltage VIL DVDD = 3.0 V 0.5 V
DVDD = 5 V 0.8 V
Input High Voltage VIH DVDD = 3.0 V 2.4 V
DVDD = 5 V 4 V

15 ppm/°C

300 mA

nA/√Hz
nA/√Hz
nA/√Hz

11 50 µA

1 2 mA

3 mA

1 mA

0.33 mA

Rev. 0 | Page 3 of 16

ADN8810

Parameter Symbol Condition Min Typ Max Unit

INTERFACE TIMING2
Clock Frequency f

RESET

Pulsewidth

NOTES

1

With respect to AVSS.

2

See Timing Characteristics for timing specifications.

= 20 Ω

* R

SN

12.5 MHz

CLK

t

40 ns

11

Rev. 0 | Page 4 of 16

ADN8810

TIMING CHARACTERISTICS

1, 2

Tabl e 2. Timi n g C h ar a cte r isti cs

Parameter Description Min Typ Max Unit

f

SCLK Frequency 12.5 MHz

CLK

t1 SCLK Cycle Time 80 ns
t2 SCLK Width High 40 ns
t3 SCLK Width Low 40 ns
t4

t5

t6

t7

CS

Low to SCLK High Setup

CS

High to SCLK High Setup

CS

SCLK High to

SCLK High to

Low Hold

CS

High Hold

15 ns

15 ns

35 ns

20 ns

t8 Data Setup 15 ns
t9 Data Hold 2 ns
t10

t11

t12

NOTES

1

Guaranteed by design. Not production tested.

2

Sample tested during initial release and after any redesign or process change that may affect these parameters. All input signals are measured with tr = tf = 5 ns (10%

to 90% of DVDD) and timed from a voltage level of (V

CS

High Pulsewidth

RESET

Pulsewidth

CS

High to

RESET

Low Hold

+ VIH)/2.

IL

30 ns

40 ns

30 ns

t

1

SCLK

t

6

t

4

t

3

t

2

t

5

t

7

CS

SDI

RESET

t

10

t

8

t

9

A3*

*ADDRESS BIT A3 MUST BE LOGIC LOW

A2

A1 A0 D11 D10 D0

t

12

t

11

03195-0-002

Figure 2. Timing Diagram

Rev. 0 | Page 5 of 16