AD7827

·8-Bit Half-Flash ADC with 420 ns Conversion Time
200 ns Acquisition Time
·8-Lead Package
·On-Chip Track-and-Hold
·On-Chip 2.5 V Reference with 2% Tolerance
·Operating Supply Range: 3 V 6 10% and 5 V 6 10%
·Specifications @ 3 V and 5 V
·DSP/Microcontroller Compatible Serial Interface
·Automatic Power-Down at End of Conversion
·Input Ranges
0 V to 2 V, V_DD = 3 V
0 V to 2.5 V, V_DD = 5 V

V_DD to GND. . . . . . . . . . . . . . . . . . . ...... . . 0.3 V to +7 V
Digital Input Voltage to GND
(CONVST, SCLK) . . . . . . . . . . . . .. .0.3 V, V_DD + 0.3 V
Digital Output Voltage to GND
(DOUT, RFS) . . . . . . . . . . . . . .. . . 0.3 V, V_DD + 0.3 V
V_REF to GND . . . . . . . . . . . . . . . . . . .0.3 V, V_DD + 0.3 V
Analog Input Voltage to AGND . . . . . 0.3 V, V_DD + 0.3 V
Operating Temperature Range
Industrial (B Version) . . . . . . . . . . . .. 40°C to +105°C
Storage Temperature Range . . . . . . . 65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . +300°C
Plastic DIP Package, Power Dissipation . . . . . . . . 450 mW
_JA Thermal Impedance . . . . . . . . . . . .. . . +105°C/W
Lead Temperature, (Soldering 10 sec) . . . . . +260°C
SOIC Package, Power Dissipation . . . . . . . . . . . . 450 mW
_JA Thermal Impedance . . . . . . . . . . . . . . . +75°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . +215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . +220°C
ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 kV

The AD7827 is a high speed, single channel, low power, analogto- digital converter with a maximum throughput of 1 MSPS that operates from a single 3 V or 5 V supply. The AD7827 contains a track/hold amplifier, an on-chip 2.5 V reference (2% tolerance), a 420 ns 8-bit half-flash ADC and a serial interface. The serial interface is compatible with the serial interfaces of most DSPs (Digital Signal Processors). The throughput rate of the AD7827 is dependent on the clock speed of the DSP serialinterface.

The AD7827 combines the Convert Start and Power Down signals at one pin, i.e., the CONVST pin. This allows a unique automatic power-down at the end of a conversion to be implemented. The logic level on the CONVST pin is sampled at theend of a conversion and, depending on its state, the AD7827 powers down.

The AD7827 has one single-ended analog input with an input span determined by the supply voltage. With a V_DD of 3 V, the input range of the AD7827 is 0 V to 2 V and with V_DD equal to 5 V, the input range is 0 V to 2.5 V.

The parts AD7827 are available in a small, 8-lead, 0.3" wide, plastic dual-in-line package (DIP) and an 8-lead, small outline IC (SOIC).