Features: 8-Bit Half-Flash ADC with 420 ns Conversion Time
1, 4 and 8 Single-Ended Analog Input Channels Available with Input Offset Adjust
On-Chip Track-and-Hold
SNR Performance Given for Input Frequencies Up to 10 MHz
On-Chip Reference (2.5 V)
Automatic Power-Down at the End of Conversion
Wide Operating Supply Range
3 V ± 10% and 5 V 6 10%
Input Ranges
0 V to 2 V p-p, VDD = 3 V ± 10%
0 V to 2.5 V p-p, VDD = 5 V ± 10%
Flexible Parallel Interface with EOC Pulse to Allow Stand-Alone OperationApplicationData Acquisition Systems, DSP Front Ends
Disk Drives
Mobile Communication Systems, Subsampling ApplicationsPinout
SpecificationsVDD to AGND . . . . . . . . . . . . . . . . . . . . . . . . . 0.3␣ V to +7␣ V
VDD to DGND . . . . . . . . . . . . . . . . . . . . . . . . . 0.3␣ V to +7␣ V
Analog Input Voltage to AGND
VIN1 to VIN8 . . . . . . . . . . . . . . . . . . . 0.3 V to VDD + 0.3 V
Reference Input Voltage to AGND . . .. 0.3 V to VDD + 0.3␣ V
VMID Input Voltage to AGND . . . . . . .. 0.3 V to VDD + 0.3␣ V
Digital Input Voltage to DGND . . . . .. ..0.3 V to VDD + 0.3 V
Digital Output Voltage to DGND . . . ...0.3 V to VDD + 0.3 V
Operating Temperature Range
Industrial (B Version) . . . . . . . . . . . . . . . . 40°C to +85°C
Storage Temperature Range . . . . . . . . . . . .65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . .150°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
TSSOP Package, Power Dissipation . . . . . . . . . . . . .. 450 mW
JA Thermal Impedance . . . . . . . . . . . . . . . . . . . . 128°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . .220°C
ESD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..1 kV
*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 listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.
| Resolution (Bits) |
8bit |
| T-Put Rate |
2MSPS |
| # Chan |
4 |
| Supply V |
Single(+3),Single(+5) |
| Pwr Diss |
36mW |
| Interface |
Par |
| Ain Range |
2 V p-p,2.5V p-p |
| SNR (dB) |
48dB |
| Pkg Type |
DIP,SOIC,SOP |
DescriptionThe AD7822, AD7825, and AD7829 are high speed, 1-, 4-, and 8-channel, microprocessor-compatible, 8-bit analog-to-digital converters with a maximum throughput of 2 MSPS. The AD7822, AD7825, and AD7829 contain an on-chip reference of 2.5 V (2% tolerance), a track/hold amplifier, a 420 ns 8-bit half-flash ADC and a high speed parallel interface. The converters can operate from a single 3 V ± 10% and 5 V ± 10% supply.
The AD7822, AD7825, and AD7829 combine the convert start and power-down functions at one pin, i.e., theCONVST 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 after the end of a conversion when anEOC (End of Conversion) signal goes high, and if it is logic low at that point, the ADC is powered down. The AD7822 and AD7825 also have a separate power-down pin. (See Operating Modes section of the data sheet.)
The parallel interface is designed to allow easy interfacing to microprocessors and DSPs. Using only address decoding logic, the parts are easily mapped into the microprocessor address space. TheEOC pulse allows the ADCs to be used in a standalone manner. (See Parallel Interface section of the data sheet.)
The AD7822 and AD7825 are available in a 20-/24-lead 0.3" wide, plastic dual-in-line package (DIP), a 20-/24-lead small outline IC (SOIC) and a 20-/24-lead thin shrink small outline package (TSSOP). The AD7829 is available in a 28-lead 0.6" wide, plastic dual-in-line package (DIP), a 28-lead small outline IC (SOIC) and in a 28-lead thin shrink small outline package (TSSOP).
AD7825 Data Sheet
