Features: `10-Bit ADC with 2.3 s Conversion Time
`The AD7811 has Four Single-Ended Inputs that Can Be Configured as Three Pseudo Differential Inputs with Respect to a Common, or as Two Independent Pseudo Differential Channels
`The AD7812 has Eight Single-Ended Inputs that Can Be Configured as Seven Pseudo Differential Inputs with Respect to a Common, or as Four Independent Pseudo Differential Channels
`Onboard Track and Hold
`Onboard Reference 2.5 V± 2.5%
`Operating Supply Range: 2.7 V to 5.5 V
`Specifications at 2.7 V3.6 V and 5 V± 10%
`DSP-/Microcontroller-Compatible Serial Interface
`High Speed Sampling and Automatic Power-Down Modes
`Package Address Pin on the AD7811 and AD7812 Allows Sharing of the Serial Bus in Multipackage Applications
`Input Signal Range: 0 V to VREF
`Reference Input Range: 1.2 V to VDD
Pinout
SpecificationsVDD to DGND . . . . . . . . . . . . . . . . . . . .. . . . . 0.3 V to +7 V
Digital Input Voltage to DGND (CONVST, SCLK, RFS, TFS,
DIN, A0) . . . . . . . . . . . . . . . . . . . . . 0.3 V, VDD + 0.3 V
Digital Output Voltage to DGND (DOUT)
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V, VDD + 0.3 V
REFIN to AGND . . . . . . . . . . . . . . . .. . . 0.3 V, VDD + 0.3 V
Analog Inputs
VIN1VIN4 (AD7811) . . . . . . . . . . . . 0.3 V, VDD + 0.3 V
VIN1VIN8 (AD7812) . . . . . .. . . . . . 0.3 V, VDD + 0.3 V
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 . . . . . . . . . . .. . . . . . 115°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . 220°C
| Resolution (Bits) |
10bit |
| T-Put Rate |
350kSPS |
| # Chan |
8 |
| Supply V |
Single(+3),Single(+3.3),Single(+5) |
| Pwr Diss (max) |
10.5mW |
| Interface |
Ser |
| Ain Range |
(Vref) p-p,Uni (Vref) |
| SNR (dB) |
n/a |
| Pkg Type |
DIP,SOIC,SOP |
DescriptionThe AD7811 and AD7812 are high speed, low power, 10-bit A/D converters that operate from a single 2.7 V to 5.5 V supply. The devices contain a 2.3 s successive approximation A/D converter, an on-chip track/hold amplifier, a 2.5 V on-chip reference and a high speed serial interface that is compatible with the serial interfaces of most DSPs (Digital Signal Processors) and microcontrollers. The user also has the option of using an external reference by connecting it to the VREF pin and setting the EXTREF bit in the control register. The VREF pin may be tied to VDD. At slower throughput rates the power-down mode may be used to automatically power down between conversions. The control registers of the AD7811 and AD7812 allow the input channels to be configured as single-ended or pseudo differential. The control register also features a software convert start and a software power-down. Two of these devices can share the same serial bus and may be individually addressed in a multipackage application by hardwiring the device address pin. The AD7811 is available in a small, 16-lead 0.3" wide, plastic dual-in-line package (mini-DIP), in a 16-lead 0.15" wide, Small Outline IC (SOIC) and in a 16-lead, Thin Shrink Small Outline Package (TSSOP). The AD7812 is available in a small, 20-lead 0.3" wide, plastic dual-in-line package (mini-DIP), in a 20-lead, Small Outline IC (SOIC) and in a 20-lead, Thin Shrink Small Outline Package (TSSOP).
AD7812 Data Sheet
