32.16.1 Internal Reference Characteristics
Operating conditions:
- VDD = 1.8 to 5.5V
- Temperature = -40°C to 125°C
- DUTYCYC = 25%
- CLKADC = 13 * fADC
- SAMPCAP is 10 pF for 0.55V reference, while it is set to 5 pF for VREF ≥ 1.1V
- Applies for all allowed combinations of VREF selections and Sample Rates unless otherwise noted
| Symbol | Description | Conditions | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|---|---|
| VDD | Supply voltage | CLKADC ≤ 1.5 MHz | 1.8 | - | 5.5 | V |
| CLKADC > 1.5 MHz | 2.7 | - | 5.5 | |||
| VREF | Reference voltage | REFSEL = Internal reference | 0.55 | - | VDD-0.5 | V |
| REFSEL = External reference | 1.1 | VDD | ||||
| REFSEL = VDD | 1.8 | - | 5.5 | |||
| CIN | Input capacitance | SAMPCAP = 5 pF | - | 5 | - | pF |
| SAMPCAP = 10 pF | - | 10 | - | |||
| RIN | Input resistance | - | 14 | - | kΩ | |
| VIN | Input voltage range | 0 | - | VREF | V | |
| IBAND | Input bandwidth | 1.1V ≤ VREF | - | - | 57.5 | kHz |
| Symbol | Description | Conditions | Min. | Typ. | Max. | Unit |
|---|---|---|---|---|---|---|
| fADC | Sample rate | 1.1V ≤ VREF | 15 | - | 115 | ksps |
| 1.1V ≤ VREF (8-bit resolution) | 15 | - | 150 | |||
| VREF = 0.55V (10 bits) | 7.5 | - | 20 | |||
| CLKADC | Clock frequency | VREF = 0.55V (10 bits) | 100 | - | 260 | kHz |
| 1.1V ≤ VREF (10 bits) | 200 | - | 1500 | |||
| 1.1V ≤ VREF (8-bit resolution) | 200 | - | 2000 | |||
| Ts | Sampling time | 2 | 2 | 33 | CLKADC cycles | |
| TCONV | Conversion time (latency) | Sampling time = 2 CLKADC | 8.7 | - | 50 | µs |
| TSTART | Start-up time | Internal VREF | - | 22 | - | µs |
Note:
- These parameters are for design guidance only and are not production tested.
| Symbol | Description | Conditions | Min. | Typ. | Max. | Unit | |
|---|---|---|---|---|---|---|---|
| Res | Resolution | - | 10 | - | bit | ||
| INL | Integral Non-linearity | REFSEL = INTERNALVREF = 0.55V | fADC = 7.7 ksps | - | 1.0 | 3.0 | LSB |
| REFSEL = INTERNAL or VDD | fADC = 15 ksps | - | 1.0 | 3.0 | |||
| REFSEL = INTERNAL or VDD1.1V ≤ VREF | fADC = 77 ksps | - | 1.0 | 3.0 | |||
| fADC = 115 ksps | - | 1.2 | 3.0 | ||||
| DNL(1) | Differential Non-linearity | REFSEL = INTERNALVREF = 0.55V | fADC = 7.7 ksps | - | 0.6 | 1.3 | LSB |
| REFSEL = INTERNALVREF = 1.1V | fADC = 15 ksps | - | 0.4 | 1.2 | |||
| REFSEL = INTERNAL or VDD1.5V ≤ VREF | fADC = 15 ksps | - | 0.4 | 1.0 | |||
| REFSEL = INTERNAL or VDD1.1V ≤ VREF | fADC = 77 ksps | - | 0.4 | 1.0 | |||
| REFSEL = INTERNAL1.1V ≤ VREF | fADC = 115 ksps | - | 0.5 | 1.6 | |||
| REFSEL = VDD1.8V ≤ VREF | fADC = 115 ksps | - | 0.9 | 2.0 | |||
| EABS | Absolute accuracy | REFSEL = INTERNALVREF = 1.1V | T = [0-105]°CVDD = [1.8V-3.6V] | - | <10 | 30 | LSB |
| VDD = [1.8V-3.6V] | - | <15 | 40 | ||||
| REFSEL = VDD | - | 2.5 | 5 | ||||
| REFSEL = INTERNAL | - | <35 | 65 | ||||
| EGAIN | Gain error | REFSEL = INTERNALVREF = 1.1V | T = [0-105]°CVDD = [1.8V-3.6V] | -25 | ±15 | 25 | LSB |
| VDD = [1.8V-3.6V] | -35 | ±20 | 35 | ||||
| REFSEL = VDD | -1 | 2 | 4 | ||||
| REFSEL = INTERNAL | -60 | ±35 | 60 | ||||
| EOFF | Offset error | REFSEL = INTERNALVREF = 0.55V | -5 | -1 | 2 | LSB | |
| REFSEL = INTERNAL1.1V ≤ VREF | -4 | -0.5 | 2 | LSB | |||
Note:
- A DNL error of less than or equal to 1 LSB ensures a monotonic transfer function with no missing codes.
- These parameters are for design guidance only and are not production tested.
- Reference setting and fADC must fulfill the specification in “Clock and Timing Characteristics” and “Power Supply, Reference, and Input Range” tables.