Functional Specifi cations
Positive Supply, pin 28 + 18V
Negative Supply, pin 31 - 18V
Logic Supply Voltage, pin 16 + 5.5V
Digital Input Voltage, pins 14, 21, 32 +5.5V
Analog Input Voltage, pin 30 ± 15V
Absolute Maximum Ratings
Typical at 25°C, ± 15V and + 5V supplies unless otherwise noted.
Inputs
Analog Input Ranges, unipolar 0 to + 5V, 0 to + 10V
Analog Input Ranges, bipolar ± 2.5V, ± 5V, ± 10V
Input Impedance1 100 megohms
Input Bias Current1 50 nA typical, 200 nA max.
Start Conversion 2V min. to + 5.5V max. positive pulse with 100
nsec. duration min. Rise and fall times <30
nsec. Logic high to low transition resets
converter and initiates next conversion.
Loading: 2 TIL loads
Sample Control Input Logic high = hold
Logic low = sample
Loading: 1 TTL load
Outputs2
Parallel Output Data 12 parallel lines of data held until
next conversion command.
V
OUT ("O")≤ +0.4V
V
OUT ("1")≥ +2.4V
Coding, unipolar Complementary Binary
Coding, bipolar Complementary Offset Binary
End of Conversion (status) Conversion status signal. Output is logic high
during reset and conversion and low when
conversion is complete.
Sample-Hold Performance3
Input Offset Drift 25 µV/°C
AcquisitionTime,10V to 0.01% 6 µsec.
Bandwidth 1 MHz
Aperture Delay Time 100 nsec.
Aperture Uncertainty Time 10 nsec.
Sample to Hold Error 2.5 mV max.
Hold Mode Droop 200 nV/µsec. max.
Hold Mode Feedthrough 0.01% max.
Converter Performance
Resolution 12 bits (1 part in 4096)
Nonlinearity ± ½ LSB max.
Differential Nonlinearity ± ¾ LSB max.
Temp. Coeffi cient of Gain ± 20 ppm/°C max.
Temp. Coeffi cient of Zero, unipolar ± 5 ppm/°C of FSR max.
Temp. Coeffi cient of Offset, bipolar ± 10 ppm/°C of FSR max.
Differential Nonlinearity Tempco ± 2 ppm/°C of FSR
MIssing Codes None over oper. temp. range
Conversion Time 9 μsec. max.
Power Supply Rejection 0.004%/% max.
Power Requirements
Power Suppy Voltage + 15V dc ±0.5V at 20 mA
-15V dc ± 0.5V at 25 mA
+5V dc ±0.25V at 85 mA
Physical/Environmental
Operating Temp. Range, Case O°C to 70°C (BMC, BMC-C)
-40°C to +100°C (BME, BME-C)
-55°C to +125°C (BMM, BMM-QL)
Storage Temperature Range -65°C to +150°C
Package Type 32 pin ceramic
Pins 0.010 x 0.018 inch Kovar
Weight 0.5 ounces (14 grams)
FOOTNOTES:
1. For sample-hold input
2. All digital outputs can drive 2 TTL loads
3. For 1000 pF external hold capacitor
TECHNICAL NOTES
1. It is recommended that the ±15V power input pins both be bypassed to ground with a 0.01 μF ceramic capaci-
tor in parallel with a 1 μF electrolytic capacitor and the +5V power input pin be bypassed to ground with a 1 μF
electrolytic capacitor as shown in the connection diagrams. In addition, pin 27 should be bypassed to ground
with a 0.01 μF ceramic capacitor. These precautions will assure noise free operation of the converter.
2. Digital Common (pin 15) and Analog Common (pin 26) are not connected together internally, and therefore must
be connected as directly as possible externally. It is recommended that a ground plane be run underneath the
case between the two commons. Analog ground and ±15V power ground should be run to pin 26 whereas
digital ground and +5V dc ground should be run to pin 15.
3. External adjustment of zero or offset and gain are provided for by trimming potentiometers connected as shown
in the connection diagrams. The potentiometer values can be between 10K and 100K ohms and should be
100 ppm/ °C, cermet types. The adjustment range is ±0.5% of FSR for zero or offset and ±0.3% for gain. The
trimming pots should be located as close as possible to the converter to avoid noise pickup. Calibration of the
ADC-HS12B is performed with the sample-hold connected and operating dynamically. This results in adjusting
out the sample-hold errors along with the A/D converter. For slow throughput applications it is recommended
that a 0.01 μF hold capacitor be used for best accuracy. With this value the acquisition time becomes 25
microseconds and the external timing must be adjusted accordingly.
4. The recommended timing shown in the Timing Diagram allows 6 microseconds for the sample-hold acquisition
and then 1 microsecond after the sample-hold goes into the hold mode to allow for output settling before the
A/D begins its conversion cycle.
5. Short cycled operation results in shorter conversion times where the conversion can be truncated to less than
12 bits. This is done by connecting pin 14 to the output bit following the last bit desired. For example, for an
8-bit conversion, pin 14 is connected to bit 9 output. Maximum conversion times are given for short-cycled
conversions in the Table.
6. Note that output coding is complementary coding. For unipolar operation it is complementary binary and for
bipolar operation it is complementary offset binary. In cases where bipolar coding of offset binary is required, this
can be achieved by inverting the analog input to the converter (using an operational amplifi er connected for gain
of -1.0000). The converter is then calibrated so that - FS analog input gives an output code of 0000 0000 0000,
and + FS - 1 LSB gives 1111 1111 1111.
7. These converters dissipate 1.81 watts maximum of power. The case to ambient thermal resistance is approxi-
mately 25°C per watt. For ambient temperatures above 50°C, care should be taken not to restrict air circulation
in the vicinity of the converter.
8. These converters can be operated with an external clock. To accomplish this, a negative pulse train is applied
to START CONVERT (Pin 21). The rate of the external clock must be lower than the rate of the internal clock.
The pulse width of the external clock should be between 100 nanoseconds and 300 nanoseconds. Each N bit
conversion cycle requires a pulse train of N + 1 clock pulses for completion, e.g., an 8-bit conversion requires
9 clock pulses for completion. A continuous pulse train may be used for consecutive conversions, resulting in
an N bit conversion every N + 1 pulses, or the E.O.C. output may be used to gate a continuous pulse train for
single conversions.
®®
DATEL • 11 Cabot Boulevard, Mansfi eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com
ADC-HS12B
12-Bit A/D Converter with Sample-Hold
26 Jun 2012 MDA_ADCHS-12B.B03 Page 2 of 4