Single-Supply Differential
18-Bit ADC Driver
Preliminary Technical Data
ADA4941-1
Rev. PrA
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: 781.329.4700
www.analog.com
Fax: 781.461.3113
2005 Analog Devices, Inc. All rights reserved.
FEATURES
Single-ended-to-differential converter
Ultralow distortion
120 dBc THD @ 10 kHz
Low noise
97 dB SNR @ 100 kHz, V
O
= 4 V p-p
Extremely low power
2.1 mA (3 V supply)
High input impedance
Easy-to-use gain adjustment
No external components for G = +2
External resistors can be used for additional gain
High speed
32 MHz, -3 dB bandwidth (G = +2)
Fast settling time
Rail-to-rail output
Disable
Wide supply voltage range: 2.7 V to 12 V
Available in space-saving packaging: 3 mm 3 mm LFCSP
APPLICATIONS
Single supply data acquisition systems
Instrumentation
Process control
Battery-power systems
Medical instruments
FUNCTIONAL BLOCK DIAGRAM
DIS
4
3
2
1
IN+
OUT
OUT+
V+
REF
IN
V
7
8
5
6
05704-001
Figure 1.
GENERAL DESCRIPTION
The ADA4941-1 is a low power, differential driver for 16- to 18-
bit ADCs. Configured in an easy-to-use, single-ended-to-
differential G = +2 configuration, the ADA4941-1 requires no
external components to drive ADCs with differential inputs
provided that the IN- pin is tied to the OUT+ pin. A resistive
network around the IN- pin can be used for additional gain as
needed. The ADA4941-1 provides essential benefits, such as
low distortion and high SNR, that are required for driving high
resolution ADCs.
With a wide input voltage range (0 V to 4 V on a single 5 V
supply), rail-to-rail output, and high input impedance, the
ADA4941-1 is designed to drive single-supply ADCs found in a
variety of low power applications, including battery-operated
instruments and single-supply data acquisition systems.
The ADA4941-1 is manufactured on ADI's proprietary 2
nd
generation XFCB process that enables the single-ended-to-
differential converter to achieve 18-bit performance using only
2.1 mA of supply current.
The ADA4941-1 is ideal for driving 16- to 18-bit differential
PulSARTM ADCs such as the AD7690 and AD7691.
The ADA4941-1 is available in a small 8 lead LFCSP packaging
as well as 8-lead SOIC packaging. The ADA4941-1 is rated to
work over the extended industrial temperature range, -40C to
+125C.
ADA4941-1
Preliminary Technical Data
Rev. PrA | Page 2 of 6
TABLE 0F CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
General Description ......................................................................... 1
Specifications .....................................................................................3
Outline Dimensions ..........................................................................6
Ordering Guide .............................................................................6
REVISION HISTORY
10/05--Revision PrA: Preliminary Version
Preliminary Technical Data
ADA4941-1
Rev. PrA| Page 3 of 6
SPECIFICATIONS
T
A
= 25C, V
S
= 3 V, unless otherwise noted.
Table 1.
Parameter Conditions
Min
Typ
Max
Unit
DYNAMIC PERFORMANCE
-3 dB Bandwidth
V
O
= 0.1 V p-p
30
MHz
V
O
= 2.0 V p-p
6.6
MHz
Overdrive Recovery Time
300
ns
Slew Rate
V
O
= 2 V step
22.5
V/s
Settling Time 0.0004%
V
O
= 2 V p-p step
0.3
s
NOISE/DISTORTION PERFORMANCE
THD f
C
= 10 kHz, V
O
= 2 V p-p
105
dBc
f
C
= 1 MHz, V
O
= 2 V p-p
57
dBc
SNR f
C
= 100 kHz, V
O
= 2 V p-p
91
dB
RTO Voltage Noise
f = 100 kHz
nV/Hz
Input Current Noise
f = 100 kHz
1
pA/Hz
DC PERFORMANCE
Differential Input Offset Voltage
0.2
.5
mV
Differential Input Offset Voltage Drift
V/C
Common-Mode Offset Voltage
mV
Common-Mode Offset Voltage Drift
V/C
Input Bias Current
IN and REF
2.2
A
Input Offset Current
IN and REF
0.2
A
Gain
(+OUT - -OUT)/(IN - REF)
2
V/V
Gain Error
0.1
%
Gain Error Drift
0.01
%/C
INPUT CHARACTERISTICS
Input Resistance
IN and REF
12
M
Input Capacitance
IN and REF
2
pF
Input Common-Mode Voltage Range
0.1
2
V
Common-Mode Rejection Ratio
V
CM
=2.5 V
110
dB
OUTPUT CHARACTERISTICS
Output Voltage Swing: VON
R
L
= 1k
0.1 to 2.9
V
VOP R
L
= 1k
0.1 to 2.9
V
Output Current
25
mA
Capacitive Load Drive
pF
POWER SUPPLY
Operating Range
2.7
12
V
Quiescent Current
2.1
mA
Quiescent Current--Disable
30
A
Power Supply Rejection Ration
+PSRR
110
dB
-PSRR
110
dB
DISABLE
V
DIS
High
1.8
V
V
DIS
Low
1.6
V
Input Current V
DIS
= HIGH/LOW
5/10
A
Turn-On Time
30
s
Turn-Off Time
0.65
s
ADA4941-1
Preliminary Technical Data
Rev. PrA | Page 4 of 6
T
A
= 25C, V
S
= 5 V, unless otherwise noted.
Table 2.
Parameter Conditions
Min
Typ
Max
Unit
DYNAMIC PERFORMANCE
-3 dB Bandwidth
V
O
= 0.1 V p-p
31
MHz
V
O
= 2.0 V p-p
7.0
MHz
Overdrive Recovery Time
0 V to 5 V step overdrive
350
ns
Slew Rate
V
O
= 2 V step
25
V/s
Settling Time 0.0004%
V
O
= 6 V p-p step
610
ns
NOISE/DISTORTION PERFORMANCE
THD f
C
= 10 kHz, V
O
= 2 V p-p
120
dBc
f
C
= 1 MHz, V
O
= 2 V p-p
72
dBc
SNR f
C
= 100 kHz, V
O
= 4 V p-p, fb = 2 MHz
97
dB
RTO Voltage Noise
f = 100 kHz
nV/Hz
Input Current Noise
f = 100 kHz
pA/Hz
DC PERFORMANCE
Differential Input Offset Voltage
0.2
.5
mV
Differential Input Offset Voltage Drift
V/C
Common-Mode Offset Voltage
0.1
.25
mV
Common-Mode Offset Voltage Drift
V/C
Input Bias Current
IN and REF
2.2
A
Input Offset Current
IN and REF
0.2
A
Gain
(OUT+ - OUT-)/(IN+ - REF)
2
V/V
Gain Error
0.1
%
Gain Error Drift
0.01
%/C
INPUT CHARACTERISTICS
Input Resistance
IN and REF
12
M
Input Capacitance
IN and REF
2
pF
Input Common-Mode Voltage Range
0.1
4
V
Common-Mode Rejection Ratio
V
CM
= 2.5 V
110
dB
OUTPUT CHARACTERISTICS
Output Voltage Swing: OUT-
R
L
= 1 k
0.1 to 4.9
V
OUT+ R
L
= 1 k
0.1 to 4.9
V
Output Current
30
mA
Capacitive Load Drive
pF
POWER SUPPLY
Operating Range
2.7
12
V
Quiescent Current
2.2
mA
Quiescent Current--Disable
40
A
Power Supply Rejection Ration
+PSRR
110
dB
-PSRR
110
dB
DISABLE
V
DIS
High
3.8
V
V
DIS
Low
3.6
V
Input Current V
DIS
= HIGH/LOW
5/12
A
Turn-On Time
30
s
Turn-Off Time
0.65
s
Preliminary Technical Data
ADA4941-1
Rev. PrA| Page 5 of 6
T
A
= 25C, Vs = 5 V, unless otherwise noted.
Table 3.
Parameter Conditions
Min
Typ
Max
Unit
DYNAMIC PERFORMANCE
-3 dB Bandwidth
V
O
= 0.1 V p-p
32.5
MHz
V
O
= 2.0 V p-p
7.5
MHz
Overdrive Recovery Time
-5 V to +5 V step overdrive
400
ns
Slew Rate
V
O
= 2 V step
26.5
V/s
Settling Time 0.0005%
V
O
= 12 V p-p step
980
ns
NOISE/DISTORTION PERFORMANCE
THD f
C
= 10 kHz, V
O
= 2 V p-p
120
dBc
f
C
= 1 MHz, V
O
= 2 V p-p
74
dBc
SNR f
C
= 100 kHz, V
O
= 4 V p-p, fb = 2 MHz
97
dB
RTO Voltage Noise
f = 100 kHz
nV/Hz
Input Current Noise
f = 100 kHz, IN+ and REF
pA/Hz
DC PERFORMANCE
Differential Input Offset Voltage
0.2
0.5
mV
Differential Input Offset Voltage Drift
V/C
Common-Mode Offset Voltage
0.1
0.25
mV
Common-Mode Offset Voltage Drift
V/C
Input Bias Current
IN+ and REF
2.2
A
Input Offset Current
IN+ and REF
0.2
A
Gain
(OUT+ - OUT-)/(IN+ - REF)
2
V/V
Gain Error
0.1
%
Gain Error Drift
0.01
%/C
INPUT CHARACTERISTICS
Input Resistance
IN+ and REF
12
M
Input Capacitance
IN+ and REF
2
pF
Input Common-Mode Voltage Range
-4.9
+4
V
Common-Mode Rejection Ratio
V
CM
= 2.5 V
110
dB
OUTPUT CHARACTERISTICS
Output Voltage Swing: OUT-
R
L
= 1k
-4.9 to +4.9
V
OUT+ R
L
= 1k
-4.9 to +4.9
V
Output Current
40
mA
Capacitive Load Drive
pF
POWER SUPPLY
Operating Range
2.7
12
V
Quiescent Current
2.5
mA
Quiescent Current--Disable
50
A
Power Supply Rejection Ration
+PSRR
110
dB
-PSRR
110
dB
DISABLE
V
DIS
High
3.8
V
V
DIS
Low
3.6
V
Input Current V
DIS
= HIGH/LOW
5/16
A
Turn-On Time
30
s
Turn-Off Time
0.65
s
ADA4941-1
Preliminary Technical Data
Rev. PrA | Page 6 of 6
OUTLINE DIMENSIONS
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
0.50 (0.0196)
0.25 (0.0099)
45
8
0
1.75 (0.0688)
1.35 (0.0532)
SEATING
PLANE
0.25 (0.0098)
0.10 (0.0040)
4
1
8
5
5.00 (0.1968)
4.80 (0.1890)
4.00 (0.1574)
3.80 (0.1497)
1.27 (0.0500)
BSC
6.20 (0.2440)
5.80 (0.2284)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
COMPLIANT TO JEDEC STANDARDS MS-012AA
Figure1. 8-Lead Standard Small Outline Package Narrow Body [SOIC] (R-8)--Dimensions shown in millimeters and (inches)
1
EXPOSED
PAD
(BOTTOM VIEW)
0.50
BSC
0.60 MAX
PIN 1
INDICATOR
1.50
REF
0.50
0.40
0.30
0.25
MIN
0.45
2.75
BSC SQ
TOP
VIEW
12 MAX
0.80 MAX
0.65 TYP
SEATING
PLANE
PIN 1
INDICATOR
0.90
0.85
0.80
0.30
0.23
0.18
0.05 MAX
0.02 NOM
0.20 REF
1.90
1.75
1.60
4
1.60
1.45
1.30
3.00
BSC SQ
5
8
Figure 2. 8-Lead Lead Frame Chip Scale Package [LFCSP], 3 mm 3 mm Body (CP-8-2)--Dimensions shown in millimeters
ORDERING GUIDE
Model
Temperature Range
Package Description
Package Option
Branding
ADA4941-1YRZ
1
40C to +125C
8-Lead Small Outline Package (SOIC)
R-8
ADA4941-1YRZ-RL
1
40C to +125C
8-Lead Small Outline Package (SOIC)
R-8
ADA4941-1YRZ-R7
1
40C to +125C
8-Lead Small Outline Package (SOIC)
R-8
ADA4941-1YCPZ-R2
1
40C to +125C
8-Lead Lead Frame Chip Scale Package (LFCSP)
CP-8-2
H9C
ADA4941-1YCPZ-RL
1
40C to +125C
8-Lead Lead Frame Chip Scale Package (LFCSP)
CP-8-2
H9C
ADA4941-1YCPZ-R7
1
40C to +125C
8-Lead Lead Frame Chip Scale Package (LFCSP)
CP-8-2
H9C
1
Z = Pb-free part.
2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
PR05704-0-10/05(PrA)
PDF 
ZIP