SPT SPT774BCJ, SPT774BCN, SPT774BCS, SPT774CCJ, SPT774CCN Datasheet

SPT774

FAST, COMPLETE 12-BIT µP COMPATIBLE

A/D CONVERTER WITH SAMPLE/HOLD

FEATURES

• Improved Higher Performance Version of the HADC574Z

• Complete 12-Bit A/D Converter with Sample/Hold,
Reference and Clock

• Low Power Dissipation (120 mW Max)

• 12-Bit Linearity (Over Temp)

•8 µs Max Conversion Time

• Single +5 V Supply

• Full Bipolar and Unipolar Input Range

GENERAL DESCRIPTION

The SPT774 is a complete, 12-bit successive approximation
A/D converter manufactured in CMOS technology. The de­vice is an improved version of the HADC574Z. Included on
chip are an internal reference, clock, and a sample-and-hold.
The S/H is an additional feature not available on similar
devices.

The SPT774 features 8 µs (max) conversion time of 10 or
20 V input signals. Also, a three-state output buffer is added
for direct interface to an 8-, 12- or 16-bit µP bus.

APPLICATIONS

• Data Acquisition Systems

• 8 or 12-Bit µP Input Functions

• Process Control Systems

• Test and Scientific Instruments

• Personal Computer Interface

The SPT774 has standard bipolar and unipolar input ranges
of 10 V and 20 V that are controlled by a bipolar offset pin and
laser trimmed for specified linearity, gain and offset accuracy.

The power supply is +5 V. The device also has an optional
mode control voltage which may be used depending on the
application. With a maximum dissipation of 120 mW at the
specified voltages, power consumption is about five times
lower than that of currently available devices.

The SPT774 is available in 28-lead ceramic sidebrazed DIP,
PDIP and SOIC packages in the commercial temperature
range.

BLOCK DIAGRAM

Signal Processing Technologies, Inc.

Phone: [phone] FAX: [phone] Website: http://www.spt.com E-Mail: [e-mail]

Output

Nibble A Nibble B Nibble C

Three-State Buffers And Control

STS

Clock

Control Logic

A

12/8 CS R/C

oCE

12-Bit SAR

Comp

+

-

Ref Out

Ref

Capacitance

Offset/Gain

Trim

20 V In
10 V In
BIP Off

AGND

4755 Forge Road, Colorado Springs, Colorado 80907, USA

12-Bit

DAC

ABSOLUTE MAXIMUM RATINGS (Beyond which damage may occur) 1 25 °C

Supply Voltages

Mode Control Voltage (VEE to DGND) ....................0 to +7 V

Logic Supply Voltage (VDD to DGND) ...................0 to +7 V

Analog to Digital Ground (AGND to DGND) .................±1 V

Input Voltages

Control Input Voltages (to DGND)

(CE, CS, Ao, 12/8, R/C)......................... -0.5 to VDD +0.5 V

Analog Input Voltage (to AGND)

(REF IN, BIP OFF, 10 VIN) ......................................±16.5 V

20 V VIN Input Voltage (to AGND) ..............................±24 V

Note: Operation at any Absolute Maximum Rating is not implied. See Operating Conditions for proper nominal applied

conditions in typical applications.

Output

Reference Output Voltage ..............Indefinite Short to GND

Momentary Short to V

Temperature

Operating Temperature, Ambient .................... 0 to +70 °C

Junction.........................+165 °C

Lead Temperature, (Soldering 10 Seconds)...........+300 °C

Storage Temperature....................................-65 to +150 °C

ELECTRICAL SPECIFICATIONS

DD

TA = T

PARAMETER CONDITIONS LEVEL MIN TYP MAX MIN TYP MAX UNITS

MIN

to T

MAX

, V

EE

= 0 to +5 V, V

TEST TEST SPT774C SPT774B

= +5 V, fS = 117 kHz, fIN = 10 kHz, unless otherwise specified..

DD

DC ELECTRICAL CHARACTERISTICS

Resolution VI 12 12 Bits
Linearity Error TA= 0 to +70 °CVI ±1 ±0.5 LSB
Differential Linearity No Missing Codes VI 12 12 Bits
Unipolar Offset; 10 V, 20 V +25 °C Adjustable to Zero VI ±2 ±2 LSB
Bipolar Offset; ±5 V, ±10 V +25 °C Adjustable to Zero VI ±10 ±4 LSB
Full Scale Calibration Error
Full Scale Calibration Error1No Adjustment to Zero

Temperature Coefficients Using Internal Reference

Unipolar Offset V ±1.0 ±1.0 ppm/°C
Bipolar Offset V ±2.0 ±2.0 ppm/°C
Full Scale Calibration V ±12 ±12 ppm/°C

Power Supply Rejection Max change in full VI ±0.5 ±0.5 LSB

+4.75 V<VDD<+5.25 V scale calibration

Analog Input Ranges

Bipolar VI -5 +5 -5 +5 Volts

Unipolar VI 0 +10 0 +10 Volts

Input Impedance

10 Volt Span VI 8.5 12 8.5 12 kΩ
20 Volt Span VI 35 50 35 50 kΩ

1

+25 °C Adjustable to Zero VI 0.30 0.30 % of FS

TA = 0 to +70 °C V 0.47 0.37 % of FS

VI -10 +10 -10 +10 Volts

VI 0 +20 0 +20 Volts

SPT

SPT774

2 8/1/00

ELECTRICAL SPECIFICATIONS

TA = T

MIN

to T

MAX

, V

EE

= 0 to +5 V, V

= +5 V, fS = 117 kHz, fIN = 10 kHz, unless otherwise specified.

DD

TEST TEST SPT774C SPT774B

PARAMETER CONDITIONS LEVEL MIN TYP MAX MIN TYP MAX UNITS

DC ELECTRICAL CHARACTERISTICS

Power Supplies Operating
Voltage Range

V

DD

2

V

EE

Operating Current

I

DD

IEE2V

= +5 V IV 167 167 µA

EE

Power Dissipation VI 75 120 75 120 mW
Internal Reference

Voltage VI 2.4 2.5 2.6 2.4 2.5 2.6 Volts
Output Current

3

DIGITAL CHARACTERISTICS
Logic Inputs

(CE,

, R/C, Ao, 12/8)

CS

Logic 0 VI -0.5 +0.8 -0.5 +0.8 Volts
Logic1 VI 2.0 5.5 2.0 5.5 Volts

Current VI -5.0 0. 1 5.0 -5.0 0. 1 5.0 µA
Capacitance V 5 5 pF

Logic Outputs

(DB11-DB0, STS)
Logic 0 (I
Logic 1 (I

= 1.6 mA) VI +0.4 +0.4 Volts

Sink
SOURCE

= 500 µA) VI +2.4 +2.4 Volts

Leakage (High Z State, VI -5 0.1 +5 -5 0.1 +5 µA

DB11-DB0 Only)

Capacitance V 5 5 pF

AC Accuracy fS=117 kHz, fIN=10 kHz

Spurious Free Dyn. Range V 73 78 76 78 dB
Total Harmonic Distortion V -77 -72 -77 -75 dB
Signal-to-Noise Ratio V 69 72 71 72 dB
Signal-to-Noise & Distortion V 68 71 70 71 dB
(SINAD)
Intermodulation Distortion fIN=20 kHz; V -75 -75 dB

f

=23 kHz

IN2

Note 1: Fixed 50 Ω resistor from REF OUT to REF IN and REF OUT to BIP OFF.
Note 2: VEE is optional and is only used to set the mode for the internal sample/hold. When not using VEE, the pin should be treated

as a no connect. If V

is connected to 0 to -15 V, aperture delay (tAP) will increase from 20 ns (typ) to 4000 ns (typ).

EE

Note 3: Available for external loads; external load should not change during conversion.

IV +4.5 +5.5 +4.5 +5.5 Volts
IV V

DD

V

DD

Volts

IV 15 24 15 24 mA

VI 0.5 0.5 mA

SPT

SPT774

3 8/1/00

ELECTRICAL SPECIFICATIONS

TA = T

MIN

to T

MAX

, V

EE

= 0 to +5 V, V

= +5 V, fS = 117 kHz, fIN = 10 kHz, unless otherwise specified.

DD

TEST TEST SPT774C SPT774B

PARAMETER CONDITIONS LEVEL MIN TYP MAX MIN TYP MAX UNITS

AC ELECTRICAL CHARACTERISTICS

4

Convert Mode Timing

t

STS Delay from CE VI 60 200 60 200 ns

DSC

t

CE Pulse Width VI 50 30 50 30 ns

HEC

t

CS to CE Setup VI 50 20 50 20 ns

SSC

CS Low during CE High VI 50 20 50 20 ns

t

HSC

R/C to CE Setup VI 50 0 50 0 ns

t

SRC

R/C Low During CE High VI 50 20 50 20 ns

t

HRC

t

Ao to CE Setup VI 0 0 ns

SAC

Ao Valid During CE High VI 50 20 50 20 ns

t

HAC

t

Conversion Time

C

5

12-Bit Cycle VI 7.5 8 7.5 8 µs
8-Bit Cycle VI 5.5 5.9 5.5 5.9 µs

Read Mode Timing

Access Time from CE VI 75 150 75 150 ns

t

DD

t

Data Valid After CE Low VI 25 35 25 35 ns

HD

t

Output Float Delay VI 100 150 100 150 ns

HL

CS to CE Setup VI 50 0 50 0 ns

t

SSR

R/C to CE Setup VI 0 0 ns

t

SRR

t

Ao to CE Setup VI 50 25 50 25 ns

SAR

CS Valid After CE Low VI 0 0 ns

t

HSR

R/C High After CE Low VI 0 0 ns

t

HRR

t

STS Delay After Data Valid VI 75 150 375 75 150 375 ns

HS

t

Ao Valid after CE Low VI 50 50 ns

HAR

Note 4: Time is measured from 50% level of digital transitions.
Note 5: Includes acquisition time.

Figure 1 - Convert Mode Timing Diagram Figure 2 - Read Mode Timing Diagram

CE

CE
CS

R/C

Ao

STS

DB11-DB0

SPT

t

t

t

SSC

SRC

SAC

t

t

t

t

DSC

High Impedance

HSC

HRC

HAC

t

HEC

t

C

4 8/1/00

R/C

STS

DB11-DB0

CS

Ao

t

SSR

t

SRR

t

SAR

HIGH

IMPEDANCE

t

DD

t

HSR

t

HRR

t

HAR

t

HS

DATA
VALID

t

HL

t

HD

SPT774