For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
0
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS
A/D CONVERTER
Functional Diagram
Features
• 10-bit resolution
• 20/40 MSPS maximum sampling rate
• Ultra-Low Power Dissipation: 15/25 mW
• 61.6 dB SNR @ 8 MHz FIN
• Internal reference circuitry
• 1.8 V core supply voltage
• 1.7 - 3.6 V I/O supply voltage
• Parallel CMOS output
• 6 x 6 mm 40-Pin QFN (LP6HE) Package
Typical Applications
• Medical Imaging
• Portable Test Equipment
• Digital Oscilloscopes
• IF Communication
General Description
The HMCAD1041-40 is a high performance ultra
low power analog-to-digital converter (ADC). The
ADC employs internal reference circuitry, a CMOS
control interface, CMOS output data and is based
on a proprietary structure. Digital error correction is
employed to ensure no missing codes in the complete
full scale range.
Two idle modes with fast startup times exist. The entire
chip can either be put in Standby Mode or Power
Down mode. The two modes are optimized to allow
the user to select the mode resulting in the lowest
possible energy consumption during idle mode and
startup.
The HMCAD1041-40 has a highly linear THA optim-
ized for frequencies up to Nyquist. The differential
clock interface is optimized for low jitter clock sources
and supports LVDS, LVPECL, sine wave and CMOS
clock inputs.
Pin compatible with HMCAD1041-80, HMCAD1051-40
and HMCAD1051-80.
Figure 1. Functional Block Diagram
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Electrical Specications
DC Electrical Specications
AVDD= 1.8V, DVDD= 1.8V, DVDDCK= 1.8V, OVDD= 2.5V, 20/40 MSPS clock, 50% clock duty cycle, -1 dBFS 8 MHz input signal, unless otherwise noted
Parameter Condition Min Typ Max Unit
DC Accuracy
No missing codes Guaranteed
Offset error Midscale offset 1 LSB
Gain error Full scale range deviation from typical ± 6 %FS
DNL Differential nonlinearity ± 0.15 LSB
INL Integral nonlinearity ± 0.2 LSB
VCM Common mode voltage output VAVDD/2 V
Analog Input
Input common mode Analog input common mode voltage VCM -0.1 VCM +0.2 V
Full scale range Differential input voltage range 2 Vpp
Input capacitance Differential input capacitance 2 pF
Bandwidth Input Bandwidth 500 MHz
Power Supply
Core Supply Voltage Supply voltage to all 1.8V domain pins. See Pin Conguration and
Description 1.7 1.8 2 V
I/O Supply Voltage Output driver supply voltage (OVDD). Should be higher than or equal
to Core Supply Voltage (VOVDD ≥ VDVDD)1.7 2.5 3.6 V
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
AC Electrical Specications - 20 MSPS
AVDD=1.8V, DVDD=1.8V, DVDDCK=1.8V, OVDD=2.5V, FS=20MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, unless otherwise noted.
Parameter Condition Min Typ Max Unit
Performance
SNR Signal to Noise Ratio
FIN = 2 MHz 61.7 dBFS
FIN = 8 MHz 60 61.6 dBFS
FIN =~ FS/2 61.6 dBFS
FIN = 20 MHz 61.6 dBFS
SNDR Signal to Noise and Distortion Ratio
FIN = 2 MHz 61.7 dBFS
FIN = 8 MHz 60 61.6 dBFS
FIN =~ FS/2 60.5 dBFS
FIN = 20 MHz 61.6 dBFS
SFDR Spurious Free Dynamic Range
FIN = 2 MHz 80 dBc
FIN = 8 MHz 70 81 dBc
FIN =~ FS/2 70 dBc
FIN = 20 MHz 80 dBc
HD2 Second order Harmonic Distortion
FIN = 2 MHz -90 dBc
FIN = 8 MHz -80 -90 dBc
FIN =~ FS/2 -90 dBc
FIN = 20 MHz -90 dBc
HD3 Third order Harmonic Distortion
FIN = 2 MHz -80 dBc
FIN = 8 MHz -70 -81 dBc
FIN =~ FS/2 -70 dBc
FIN = 20 MHz -80 dBc
ENOB Effective number of Bits
FIN = 2 MHz 10 bits
FIN = 8 MHz 9.7 9.9 bits
FIN =~ FS/2 9.8 bits
FIN = 20 MHz 9.9 bits
Power Supply
Analog supply current 5.7 mA
Digital supply current Digital core supply 1 mA
Output driver supply 2.5V output driver supply, sine wave input, FIN = 1 MHz, CK_EXT enabled 1.7 mA
Output driver supply 2.5V output driver supply, sine wave input, FIN = 1 MHz, CK_EXT disabled 1.2 mA
Analog power Dissipation 10.3 mW
Digital power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1 MHz, CK_EXT disabled 4.8 mW
Total power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1 MHz, CK_EXT disabled 15.1 mW
Power Down Dissipation 9.9 µW
Sleep Mode Power Dissipation, Sleep mode 7.7 mW
Clock Inputs
Max. Conversion Rate 20 MSPS
Min. Conversion Rate 3 MSPS
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
AC Electrical Specications - 40 MSPS
AVDD=1.8V, DVDD=1.8V, DVDDCK=1.8V, OVDD=2.5V, FS=40MSPS clock, 50% clock duty cycle, -1dBFS 8MHz input signal, unless otherwise noted.
Parameter Condition Min Typ Max Unit
Performance
SNR Signal to Noise Ratio
FIN = 2 MHz 61.6 dBFS
FIN = 8 MHz 60 61.6 dBFS
FIN =~ FS/2 61.6 dBFS
FIN = 30 MHz 61.5 dBFS
SNDR Signal to Noise and Distortion Ratio
FIN = 2 MHz 61.6 dBFS
FIN = 8 MHz 60 61.6 dBFS
FIN =~ FS/2 61.2 dBFS
FIN = 30 MHz 61.4 dBFS
SFDR Spurious Free Dynamic Range
FIN = 2 MHz 80 dBc
FIN = 8 MHz 70 81 dBc
FIN =~ FS/2 72 dBc
FIN = 30 MHz 80 dBc
HD2 Second order Harmonic Distortion
FIN = 2 MHz -90 dBc
FIN = 8 MHz -80 -90 dBc
FIN =~ FS/2 -85 dBc
FIN = 30 MHz -85 dBc
HD3 Third order Harmonic Distortion
FIN = 2 MHz -80 dBc
FIN = 8 MHz -70 -81 dBc
FIN =~ FS/2 -72 dBc
FIN = 30 MHz -80 dBc
ENOB Effective number of Bits
FIN = 2 MHz 9.9 bits
FIN = 8 MHz 9.7 9.9 bits
FIN =~ FS/2 9.9 bits
FIN = 30 MHz 9.9 bits
Power Supply
Analog supply current 9.3 mA
Digital supply current Digital core supply 1.7 mA
Output driver supply 2.5V output driver supply, sine wave input, FIN = 1 MHz, CK_EXT enabled 3.1 mA
Output driver supply 2.5V output driver supply, sine wave input, FIN = 1 MHz, CK_EXT disabled 2.2 mA
Analog power Dissipation 16.7 mW
Digital power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1 MHz, CK_EXT disabled 8.6 mW
Total power Dissipation OVDD = 2.5V, 5pF load on output bits, FIN = 1 MHz, CK_EXT disabled 25.3 mW
Power Down Dissipation 9.7 µW
Sleep Mode Power Dissipation, Sleep mode 11.3 mW
Clock Inputs
Max. Conversion Rate 40 MSPS
Min. Conversion Rate 3 MSPS
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Digital and Timing Specications
AVDD=1.8V, DVDD=1.8V, DVDDCK=1.8V, OVDD=2.5V, Conversion Rate: Max specied, 50% clock duty cycle, -1dBFS input signal, 5 pF capacitive
load on data outputs, unless otherwise noted
Parameter Condition Min Typ Max Unit
Clock Inputs
Duty Cycle 20 80 % high
Compliance CMOS, LVDS, LVPECL, Sine Wave
Input range Differential input swing 0.4 Vpp
Input range Differential input swing, sine wave clock input 1.6 Vpp
Input common mode
voltage Keep voltages within ground and voltage of OVDD 0.3 VOVDD -0.3 V
Input capacitance Differential 2 pF
Timing
TPD Start up time from Power Down Mode to Active Mode 900 clock
cycles
TSLP Start up time from Sleep Mode to Active Mode 20 clock
cylcles
TOVR Out of range recovery time 1 clock
cycles
T
AP Aperture Delay 0.8 ns
Єrms Aperture jitter < 0.5 ps
TLAT Pipeline Delay 12 clock
cycles
TDOutput delay (see timing diagram). 5pF load on output bits 3 10 ns
TDC Output delay relative to CK_EXT (see timing diagram) 1 6 ns
Logic Inputs
VHI High Level Input Voltage. VOVDD ≥ 3.0V 2 V
VHI High Level Input Voltage. VOVDD = 1.7V – 3.0V 0.8 ·VOVDD V
VLI Low Level Input Voltage. VOVDD ≥ 3.0V 0 0.8 V
VLI Low Level Input Voltage. VOVDD = 1.7V – 3.0V 0 0.2 ·VOVDD V
IHI High Level Input leakage Current ±10 µA
ILI Low Level Input leakage Current ±10 µA
CIInput Capacitance 3 pF
Logic Outputs
VHO High Level Output Voltage VOVDD -0.1 V
VLO Low Level Output Voltage 0.1 V
CL
Max capacitive load. Post-driver supply voltage equal to pre-driver
supply voltage VOVDD = VOCVDD
5 pF
CLMax capacitive load. Post-driver supply voltage above 2.25V (1) 10 pF
(1) The outputs will be functional with higher loads. However, it is recommended to keep the load on output data bits as low as possible
to keep dynamic currents and resulting switching noise at a minimum
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Timing Diagram
Figure 2: Timing Diagram
Absolute Maximum Ratings
Absolute maximum ratings are limiting values to be applied for short periods of time. Exposure to absolute maxi-
mum rating conditions for an extended period of time may reduce device lifetime.
Table 1:
Pin Pin Rating
AVDD VSS -0.3V to +2.3V
DVDD VSS -0.3V to +2.3V
AVSS, DVSSCK, DVSS, OVSS VSS -0.3V to +0.3V
OVDD VSS -0.3V to +3.9V
IP, IN, analog inputs and outputs VSS -0.3V to +2.3V
Digital outputs VSS -0.3V to +3.9V
CKP, CKN VSS -0.3V to +3.9V
Digital Inputs VSS -0.3V to +3.9V
Operating temperature -40 to +85 ºC
Storage temperature -60 to +150 ºC
Soldering Prole Qualication J-STD-020
ELECTROSTATIC SENSITIVE DEVICE
OBSERVE HANDLING PRECAUTIONS
Stresses above those listed under Absolute Maximum
Ratings may cause permanent damage to the device. This
is a stress rating only; functional operation of the device
at these or any other conditions above those indicated in
the operational section of this specication is not implied.
Exposure to absolute maximum rating conditions for
extended periods may affect device reliability.
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
0
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Pin Conguration and Description
Figure 3: Package Drawing, QFN 40-pin
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Table 2: Pin Function
Pin # Name Description
0 VSS Ground connection for all power domains. Exposed pad
1, 11, 16 DVDD Digital and I/O-ring pre driver supply voltage, 1.8V
2 CM_EXT Common Mode voltage output
3, 4, 7, AVDD Analog supply voltage, 1.8V
5, 6 IP, IN Analog input (non-inverting, inverting)
8 DVDDCK Clock circuitry supply voltage, 1.8V
9 CKP Clock input, non-inverting (Format: LVDS, LVPECL, CMOS/TTL, Sine Wave)
10 CKN Clock input, inverting. For CMOS input on CKP, connect CKN to ground.
12 CK_EXT_EN CK_EXT signal enabled when low (zero). Tristate when high.
13 DFRMT Data format selection. 0: Offset Binary, 1: Two’s Complement
14 PD_N Full chip Power Down mode when Low. All digital outputs reset to zero. After chip power up always apply
Power Down mode before using Active Mode to reset chip.
15 OE_N Output Enable. Tristate when high
17, 18, 25, 26,
36, 37 OVDD I/O ring post-driver supply voltage. Voltage range 1.7 to 3.6V
19 NC
20 NC
21 NC
22 D_0 Output Data (LSB)
23 D_1 Output Data
24 ORNG Out of Range ag. High when input signal is out of range
27 CK_EXT Output clock signal for data synchronization. CMOS levels
28 D_2 Output Data
29 D_3 Output Data
30 D_4 Output Data
31 D_5 Output Data
32 D_6 Output Data
33 D_7 Output Data
34 D_8 Output Data
35 D_9 Output Data (MSB)
38, 39 CM_EXTBC_1,
CM_EXTBC_0
Bias control bits for the buffer driving pin CM_EXT
00: OFF 01: 50uA
10: 500uA 11: 1mA
40 SLP_N Sleep Mode when low
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
0
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Recommended Usage
Analog Input
The analog inputs to the HMCAD1041-40 is a switched
capacitor track-and-hold amplier optimized for differ-
ential operation. Operation at common mode voltages
at mid supply is recommended even if performance
will be good for the ranges specied. The CM_EXT pin
provides a voltage suitable as common mode voltage
reference. The internal buffer for the CM_EXT voltage
can be switched off, and driving capabilities can be
changed by using the CM_EXTBC control input.
Figure 4 shows a simplied drawing of the input net-
work. The signal source must have sufficiently low
output impedance to charge the sampling capacitors
within one clock cycle. A small external resistor (e.g.
22 Ohm) in series with each input is recommended
as it helps reducing transient currents and dampens
ringing behavior. A small differential shunt capacitor at
the chip side of the resistors may be used to provide
dynamic charging currents and may improve perfor-
mance. The resistors form a low pass lter with the
capacitor, and values must therefore be determined by
requirements for the application.
Figure 4: Input conguration
DC-Coupling
Figure 5 shows a recommended conguration for DC-
coupling. Note that the common mode input voltage
must be controlled according to specied values. Pref-
erably, the CM_EXT output should be used as refer-
ence to set the common mode voltage.
Figure 5: DC coupled input with buffer
The input amplier could be inside a companion chip
or it could be a dedicated amplier. Several suitable
single ended to differential driver ampliers exist in the
market. The system designer should make sure the
specications of the selected amplier is adequate for
the total system, and that driving capabilities comply
with the HMCAD1041-40 input specications.
Detailed conguration and usage instructions must be
found in the documentation of the selected driver, and
the values given in gure 5 must be varied according
to the recommendations for the driver.
AC-Coupling
A signal transformer or series capacitors can be used
to make an AC-coupled input network. Figure 6 shows
a recommended conguration using a transformer.
Make sure that a transformer with sufficient linearity is
selected, and that the bandwidth of the transformer is
appropriate. The bandwidth should exceed the sam-
pling rate of the ADC with at least a factor of 10. It is
also important to minimize phase mismatch between
the differential ADC inputs for good HD2 performance.
This type of transformer coupled input is the preferred
conguration for high frequency signals as most differ-
ential ampliers do not have adequate performance at
high frequencies. If the input signal is traveling a long
physical distance from the signal source to the trans-
former (for example a long cable), kick-backs from the
ADC will also travel along this distance. If these kick-
backs are not terminated properly at the source side,
they are reected and will add to the input signal at the
ADC input. This could reduce the ADC performance.
To avoid this effect, the source must effectively ter-
minate the ADC kick-backs, or the traveling distance
should be very short. If this problem could not be
avoided, the circuit in gure 8 can be used.
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Figure 6: Transformer coupled input
Figure 7 shows AC-coupling using capacitors. Resis-
tors from the CM_EXT output, RCM, should be used
to bias the differential input signals to the correct volt-
age. The series capacitor, CI, form the high-pass pole
with these resistors, and the values must therefore be
determined based on the requirement to the high-pass
cut-off frequency.
Figure 7: AC coupled input
Note that startup time from Sleep Mode and Power
Down Mode will be affected by this lter as the time
required to charge the series capacitors is dependent
on the lter cut-off frequency.
If the input signal has a long traveling distance, and the
kick-backs from the ADC not are effectively terminated
at the signal source, the input network of gure 8 can
be used. The conguration in gure 8 is designed to
attenuate the kickback from the ADC and to provide
an input impedance that looks as resistive as possible
for frequencies below Nyquist. Values of the series
inductor will however depend on board design and
conversion rate. In some instances a shunt capaci-
tor in parallel with the termination resistor (e.g. 33pF)
may improve ADC performance further. This capacitor
attenuate the ADC kick-back even more, and minimize
the kicks traveling towards the source. However, the
impedance match seen into the transformer becomes
worse.
Figure 8: Alternative input network
Clock Input and Jitter Considerations
Typically high-speed ADCs use both clock edges to
generate internal timing signals. In the HMCAD1041-
40 only the rising edge of the clock is used. Hence,
input clock duty cycles between 20% and 80% are
acceptable.
The input clock can be supplied in a variety of formats.
The clock pins are AC-coupled internally. Hence a
wide common mode voltage range is accepted. Differ-
ential clock sources as LVDS, LVPECL or differential
sine wave can be connected directly to the input pins.
For CMOS inputs, the CKN pin should be connected
to ground, and the CMOS clock signal should be con-
nected to CKP. For differential sine wave clock, the
input amplitude must be at least ± 800 mVpp.
The quality of the input clock is extremely important
for high-speed, high-resolution ADCs. The contribu-
tion to SNR from clock jitter with a full scale signal at a
given frequency is shown in equation 1,
SNRjitter = 20 · log (2 · π · ƒIN · єt) (1)
where fIN is the signal frequency, and εt is the total
rms jitter measured in seconds. The rms jitter is the
total of all jitter sources including the clock generation
circuitry, clock distribution and internal ADC circuitry.
For applications where jitter may limit the obtainable
performance, it is of utmost importance to limit the
clock jitter. This can be obtained by using precise and
stable clock references (e.g. crystal oscillators with
good jitter specications) and make sure the clock dis-
tribution is well controlled. It might be advantageous
to use analog power and ground planes to ensure
low noise on the supplies to all circuitry in the clock
distribution. It is of utmost importance to avoid cross-
talk between the ADC output bits and the clock and
between the analog input signal and the clock since
such crosstalk often results in harmonic distortion.
The jitter performance is improved with reduced rise
and fall times of the input clock. Hence, optimum jitter
performance is obtained with LVDS or LVPECL clock
with fast edges. CMOS and sine wave clock inputs will
result in slightly degraded jitter performance.
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
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SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
If the clock is generated by other circuitry, it should
be re-timed with a low jitter master clock as the last
operation before it is applied to the ADC clock input.
Digital Outputs
Digital output data are presented on parallel CMOS
form. The voltage on the OVDD pin set the levels of the
CMOS outputs. The output drivers are dimensioned to
drive a wide range of loads for OVDD above 2.25V,
but it is recommended to minimize the load to ensure
as low transient switching currents and resulting noise
as possible. In applications with a large fanout or large
capacitive loads, it is recommended to add external
buffers located close to the ADC chip.
The timing is described in the Timing Diagram section.
Note that the load or equivalent delay on CK_EXT
always should be lower than the load on data outputs
to ensure sufficient timing margins.
The digital outputs can be set in tristate mode by set-
ting the OE_N signal high.
The HMCAD1041-40 employs digital offset correc-
tion. This means that the output code will be 4096 with
shorted inputs. However, small mismatches in para-
sitics at the input can cause this to alter slightly. The
offset correction also results in possible loss of codes
at the edges of the full scale range. With no offset
correction, the ADC would clip in one end before the
other, in practice resulting in code loss at the oppo-
site end. With the output being centered digitally, the
output will clip, and the out of range ags will be set,
before max code is reached. When out of range ags
are set, the code is forced to all ones for overrange
and all zeros for underrange.
Data Format Selection
The output data are presented on offset binary form
when DFRMT is low (connect to OVSS). Setting
DFRMT high (connect to OVDD) results in 2’s comple-
ment output format. Details are shown in table 3.
Table 3: Data Format Description for 2Vpp Full Scale Range
Differential Input Voltage (IP - IN) Output Data: D_9 : D_0
(DFRMT = 0, Offset Binary)
Output Data: D_9 : D_0
(DFRMT = 1, 2’s Complement)
1.0 V 11 1111 1111 01 1111 1111
+0.24mV 10 0000 0000 00 0000 0000
-0.24mV 01 1111 1111 11 1111 1111
-1.0V 00 0000 0000 10 0000 0000
Reference Voltages
The reference voltages are internally generated and
buffered based on a bandgap voltage reference. No
external decoupling is necessary, and the reference
voltages are not available externally. This simplies
usage of the ADC since two extremely sensitive pins,
otherwise needed, are removed from the interface.
Operational Modes
The operational modes are controlled with the PD_N
and SLP_N pins. If PD_N is set low, all other control
pins are overridden and the chip is set in Power Down
mode. In this mode all circuitry is completely turned off
and the internal clock is disabled. Hence, only leak-
age current contributes to the Power Down Dissipa-
tion. The startup time from this mode is longer than
for Sleep Mode as all references need to settle to their
nal values before normal operation can resume.
The SLP_N signal can be used to set the full chip in
Sleep Mode. In this mode internal clocking is disabled,
but some low bandwidth circuitry is kept on to allow for
a short startup time. However, Sleep Mode represents
a signicant reduction in supply current, and it can be
used to save power even for short idle periods.
The input clock should be kept running in all idle
modes. However, even lower power dissipation is pos-
sible in Power Down mode if the input clock is stopped.
In this case it is important to start the input clock prior
to enabling active mode.
Startup Initialization
The HMCAD1041-40 must be reset prior to normal
operation. This is required every time the power
supply voltage has been switched off. A reset is per-
formed by applying Power Down mode. Wait until a
stable supply voltage has been reached, and pull the
PD_N pin for the duration of at least one clock cycle.
The input clock must be running continuously during
this Power Down period and until active operation
is reached. Alternatively the PD pin can be kept low
during power-up, and then be set high when the power
supply voltage is stable.
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
For price, delivery and to place orders: Hittite Microwave Corporation, 2 Elizabeth Drive, Chelmsford, MA 01824
978-250-3343 tel • 978-250-3373 fax • Order On-line at www.hittite.com
Application Support: apps@hittite.com
A / D CONVERTERS - SMT
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HMCAD1041-40
v01.0411
SINGLE 10-BIT 20/40 MSPS A/D CONVERTER
Outline Drawing
Table 4: 6x6 mm QFN (40 Pin LP6H) Dimensions
Symbol Millimeter Inch
Min Typ Max Min Typ Max
A 0.9 0.035
A1 0 0.01 0.05 0 0.000 0.002
A2 0.65 0.7 0.026 0.028
A3 0.2 REF 0.008 REF
b 0.2 0.25 0.32 0.008 0.01 0.013
D 6.00 bsc 0.236 bsc
D1 5.75 bsc 0.226 bsc
D2 3.95 4.1 4.25 0.156 0.162 0.167
L 0.3 0.4 0.5 0.012 0.016 0.02
e 0.50 bsc 0.020 bsc
Θ1 0° 12° 0° 12°
F 0.2 0.008
G 0.24 0.42 0.6 0.010 0.017 0.024
Package Information
Part Number Package Body Material Lead Finish MSL [1] Package Marking [2]
HMCAD1041-40 RoHS-compliant Low Stress Injection Molded Plastic 100% matte Sn Level 2A
ASD0401
XXXX
XXXX
[1] MSL, Peak Temp: The moisture sensitivity level rating classied according to the JEDEC industry standard and to peak solder temperature.
[2] Proprietary marking XXXX, 4-Digit lot number XXXX
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.
For price, delivery, and to place orders: Analog Devices, Inc.,
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106
Phone: 781-329-4700 • Order online at www.analog.com
Application Support: Phone: 1-800-ANALOG-D
