• Superior performance over AD9713
– Improved settling time of 13 ns
– Improved glitch energy 15 pV- s
– Master-slave latches
GENERAL DESCRIPTION
The SPT9713 is a 12-bit, 100 MWPS digital-to-analog
converter designed for direct digital synthesis, high resolution imaging, and arbitrary wavef orm generation applications.
This device is pin-for-pin compatib le with the AD9713 with
significantly improved performance. The only difference
between the SPT9713 and the AD9713 is that the Latch
Enable (LE, pin 26) for the SPT9713 is rising-edge trig-
APPLICATIONS
• Fast frequency hopping spread spectrum radios
• Direct sequence spread spectrum radios
• Microwave and satellite modems
• Test & measurement instr umentation
gered (see figure 1), whereas the Latch Enable (LE, pin
26) for the AD9713 functions in the transparent mode.
The SPT9713 is a TTL-compatible device. It features a
fast settling time of 13 ns and low glitch impulse energy of
15 pV-s, which results in excellent spurious-free dynamic
range characteristics.
The SPT9713 is available in a 28-lead PLCC package in
the industrial temperature range (–40 to +85 °C).
BLOCK DIAGRAM
R
Set
Control Amp In
Ref Out
Latch Enable
Digital
Inputs
D1
through
D12
+
Control
Amp
(MSB)
Decoders
and
Drivers
(LSB)
Internal
Voltage
Reference
Latches
Switch
Network
Control
Amp Out
Ref In
I
Out
I
Out
Signal Processing Technologies, Inc.
4755 Forge Road, Colorado Springs, Colorado 80907, USA
Control Amplifier Output Current.....................±2.5 mA
Temperature
Operating Temperature .......................... –40 to +85 °C
Junction Temperature ...................................... +150 °C
CC
Lead, Soldering (10 seconds) .........................+300 °C
Storage ................................................ –65 to +150 °C
EE
Note: 1. Operation at any Absolute Maximum Rating is not implied. See
Electrical Specifications for proper nominal applied conditions
in typical applications.
ELECTRICAL SPECIFICATIONS
TA = T
PARAMETERSCONDITIONSLEVELMINTYPMAXMINTYPMAXUNITS
DC Performance
– T
MIN
, VCC = +5.0 V, V
MAX
= –5.2 V, R
EE
= 7.5 kΩ, Control Amp In = Ref Out, V
Set
= 0 V, unless otherwise specified.
OUT
TESTTESTSPT9713ASPT9713B
Resolution1212Bits
Differential LinearityI±0.5 ±0.75±1.0 ±1.25LSB
Differential LinearityMax at Full Temp.VI±1.5±2.0LSB
Integral LinearityBest FitI±0.75 ±1.0±1.0±1.5LSB
Integral LinearityMax at Full Temp.VI±1.75±2.0LSB
Output Capacitance+25 °CV1010pF
Gain Error
1
+25 °CI1.05.01.05.0% FS
Full Temp.VI8.08 . 0% FS
Gain Error TempcoFull Temp.V150150PPM/°C
Zero-Scale Offset Error+25 °CI0.52.50.52.5µA
Gain is measured as a ratio of the full-scale current to I
2
Measured as voltage at mid-scale transition to ±0.024%; RL=50 Ω.
3
Measured from the rising edge of Latch Enable to where the output signal has left a 1 LSB error band.
4
Glitch is measured as the largest single transient.
5
Calculated using IFS = 128 x (Control Amp In / R
6
SFDR is defined as the difference in signal energy between the fundamental and worst case spurious frequencies in the output spectrum window ,
which is centered at the fundamental frequency and covers the indicated span.
Set
. The ratio is nominally 128.
Set
)
SPT9713
SPT
22/15/01
Page 3
ELECTRICAL SPECIFICATIONS
TA = T
MIN
– T
MAX
, VCC = +5.0 V, V
= –5.2 V, R
EE
= 7.5 kΩ, Control Amp In = Ref Out, V
SET
= 0 V, unless otherwise specified.
OUT
TESTTESTSPT9713ASPT9713B
PARAMETERSCONDITIONSLEVELMINTYPMAXMINTYPMAXUNITS
Power Supply Requirements
Logic 1 VoltageFull Temp.VI2.02.0V
Logic 0 VoltageFull Temp.VI0.80.8V
Logic 1 CurrentFull Temp.VI2020µA
Logic 0 CurrentFull Temp.VI600600µA
Input Capacitance+25 °CV33pF
Input Setup Time – t
Input Setup Time – t
Input Hold Time – t
Input Hold Time – t
Latch Pulse Width – t
S
S
H
H
PWL, tPWH
+25 °CIV3232ns
Full Temp.IV3.53.5ns
+25 °CIV0.500.50ns
Full Temp.IV0.50.5ns
+25 °CIV5.04.05. 04.0ns
TEST LEVEL CODES
All electrical characteristics are subject to the
following conditions:
All parameters having min/max specifications
are guaranteed. The Test Level column indicates the specific device testing actually performed during production and Quality Assurance inspection. Any blank section in the data
column indicates that the specification is not
tested at the specified condition.
LEVELTEST PROCEDURE
I100% production tested at the specified temperature.
II100% production tested at TA = +25 °C, and sample tested at the
specified temperatures.
IIIQA sample tested only at the specified temperatures.
IVParameter is guaranteed (but not tested) by design and characteri-
zation data.
VParameter is a typical value for information pur poses only.
VI100% production tested at TA = +25 °C. Parameter is guaranteed
over specified temperature range.
SPT
SPT9713
32/15/01
Page 4
THEORY OF OPERATION
VOLT AGE REFERENCE
The SPT9713 uses a segmented architecture incorporating most significant bit (MSB) decoding. The four MSBs
(D1–D4) are decoded to thermometer code lines to drive
15 discrete current sinks. For the eight least significant
bits (LSBs), D5 and D6 are binary weighted and D7–D12
are applied to the R-2R network. The 12-bit decoded data
is input to internal master/slave latches. The latched data
is input to the switching network and is presented on the
output pins as complementary current outputs.
TYPICAL INTERFACE CIRCUIT
The SPT9713 requires few external components to
achieve the stated operation and performance. Figure 2
shows the typical interface requirements when using the
SPT9713 in normal circuit operation. The following sections provide descriptions of the pin functions and outline
critical performance criteria to consider for achieving optimal device performance.
POWER SUPPLIES AND GR OUNDING
The SPT9713 requires the use of +5 V and –5.2 V supplies. All supplies should be treated as analog supply
sources. This means the ground returns of the device
should be connected to the analog ground plane. All supply pins should be bypassed with .01 µF and 10 µF
decoupling capacitors as close to the device as possible .
The two grounds available on the SPT9713 are DGND
and AGND . These grounds are not tied together internal to
the device. The use of ground planes is recommended to
achieve the best perf ormance of the SPT9713. All g round,
reference and analog output pins should be tied directly to
the DAC ground plane. The DAC and system ground
planes should be separate from each other and only connected at a single point through a ferrite bead to reduce
ground noise pickup.
DIGITAL INPUTS AND TIMING
The SPT9713 uses TTL logic drivers for each data input
D1–D12 and Latch Enable. It also employs master/slave
latches to simplify digital interface timing requirements
and reduce glitch energy by synchronizing the current
switches. This is an improv ement over the AD9713, which
typically requires external latches for digital input synchronization.
When using the internal reference, Ref Out should be connected to Control Amp In and decoupled with a 0.1 µF
capacitor. Control Amp Out should be connected to Ref In
and decoupled to the analog supply. (See figure 2.)
Full-scale output current is determined by Control Amp In
and R
using the following formula:
Set
I
(FS) = (Control Amp In / R
Out
) x 128
Set
(Current Out is a constant 128 factor of the
reference current)
The internal reference is typically –1.20 V with a tolerance
of ±0.05 V and a typical drift of 50 ppm/°C. If greater accuracy or temperature stability is required, an external reference can be utilized.
OUTPUTS
The output of the SPT9713 is comprised of complementary current sinks, I
at either I
Out
or I
The sum of the two is always equal to the full-scale output
current minus one LSB.
By terminating the output current through a resistive load
to ground, an associated voltage develops. The effective
resistive load (R
(R
) in parallel with the resistive load (RL). The voltage
Out
which develops can be determined using the following
formulas:
Control Amp Out = –1.2 V, and R
I
(FS) = (–1.2 V / 7.5 kΩ) x 128 = –20.48 mA
Out
RL = 51 Ω
R
= 1.0 kΩ
Out
R
= 51 Ω || 1.0 kΩ = 48.52 Ω
Eff
V
= R
Out
Eff
x I
The resistive load of the SPT9713 can be modified to incorporate a wide variety of signal levels. Howev er , optimal
device performance is achieved when the outputs are
equivalently loaded.
and I
Out
are based upon the digital input code.
Out
) is the output resistance of the device
Eff
(FS) = 48.52 Ω x –20.48 mA
Out
. The output current levels
Out
= 7.5 kΩ
Set
= –0.994 V
Referring to figure 1, data is latched into the DAC on the
rising edge of the latch enable clock with the associated
setup and hold times. The output transition occurs after a
typical 2 ns propagation delay and settles to within ±1 LSB
in typically 13 ns. Because of the SPT9713’s rising-edge
triggering, no timing changes are required when replacing
an AD9713 operating in the transparent mode.
Out+Analog Current Output
Out–Complementary Analog Current Output
D1–D12Digital Input Bits (D12 is the LSB)
Latch EnableLatch Control Line
Ref InVoltage Reference Input
Ref OutInternal Voltage Reference Output
Normally Connected to Control Amp In
Ref GNDGround Return For Internal Voltage
Reference and Amplifier
Control Amp InNormally Connected to Ref Out If Not
Connected to External Reference
Control Amp Out Output of Internal Control Amplifier
Normally Connected to Ref In
1
R
Set
Connection for External Resistance
Reference When Using Internal Amplifier
Nominally 7.5 kΩ
Analog ReturnAnalog Return Ground
Analog V
Digital V
Digital V
EE
EE
CC
Analog Negative Supply (–5.2 V)
Digital Negative Supply (–5.2 V)
Digital Positive Supply (+5.2 V)
DGNDDigital Ground Return
1Full-Scale Current Out = 128 (Control Amp In / R
Set
)
ORDERING INFORMATION
PART NUMBERDNL/INLTEMPERATURE RANGEPACKAGE
SPT9713AIP±0.75/±1.0–40 to +85 °C28L PLCC
SPT9713BIP±1.25/±1.5–40 to +85 °C28L PLCC
Signal Processing Technologies, Inc. reserves the right to change products and specifications without notice. Permission is hereby
expressly granted to copy this literature for informational purposes only. Copying this material for any other use is strictly prohibited.
WARNING – LIFE SUPPORT APPLICATIONS POLICY – SPT products should not be used within Life Support Systems without
the specific written consent of SPT. A Life Support System is a product or system intended to support or sustain life which, if it fails,
can be reasonably expected to result in significant personal injury or death.
Signal Processing Technologies believes that ultrasonic cleaning of its products may damage the wire bonding, leading to device
failure. It is therefore not recommended, and exposure of a device to such a process will void the product warranty.
SPT9713
SPT
72/15/01
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