# AT25640B-XHL-B

**Microchip Tech** · Pre-ordered Chips · TSSOP-8

AT25640B-XHL-B from Microchip Tech, in a TSSOP-8. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

## Pinout

| Pin | Name | Type | Function |
|---|---|---|---|
| 1 | CS | input | Chip Select: the device is selected when CS is low, and when it is not selected SI is not accepted and SO stays high-impedance. |
| 2 | SO | tri_state | Serial Data Output: remains in a high-impedance state when the device is not selected or after an invalid opcode until the next falling edge of CS. |
| 3 | WP | input | Write Protect: allows normal read/write when held high, and when held low with WPEN set to one all status register writes are inhibited. |
| 4 | GND | power_in | Ground reference for the device. |
| 5 | SI | input | Serial Data Input: data is accepted only while the device is selected, and inputs are ignored while SO is in the high-impedance state during HOLD. |
| 6 | SCK | input | Serial Data Clock: always an input, which makes the device operate as a slave; the device is specified up to 20 MHz at 5.0 V. |
| 7 | HOLD | input | HOLD: when brought low while SCK is low it pauses serial communication without resetting the sequence, and it resumes when brought high while SCK is low. |
| 8 | VCC | power_in | Power supply, specified from 1.8 V to 5.5 V. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | Microchip Tech |
| Package | TSSOP-8 |
| Category | Interface ICs |
| Pins | 8 |

## Electrical characteristics

Limits as printed in the datasheet (page.json `metadata.characteristics` carries them as data).

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| Supply Voltage (1.8V range) | VCC1 | 1.8 |  | 5.5 | V |  | 4 |
| Supply Voltage (2.5V range) | VCC2 | 2.5 |  | 5.5 | V |  | 4 |
| Supply Voltage (4.5V range) | VCC3 | 4.5 |  | 5.5 | V |  | 4 |
| Supply Current, Read | ICC1 |  | 7.5 | 10 | mA | VCC = 5.0V at 20MHz, SO = Open, Read | 4 |
| Supply Current, Read/Write | ICC2 |  | 4 | 10 | mA | VCC = 5.0V at 20MHz, SO = Open, Read, Write | 4 |
| Supply Current, Read/Write at 5MHz | ICC3 |  | 4 | 6 | mA | VCC = 5.0V at 5MHz, SO = Open, Read, Write | 4 |
| Standby Current | ISB1 |  |  | 6 | μA | VCC = 1.8V, CS = VCC | 4 |
| Standby Current | ISB2 |  | 0.3 | 7 | μA | VCC = 2.5V, CS = VCC | 4 |
| Standby Current | ISB3 |  | 2 | 10 | μA | VCC = 5.0V, CS = VCC | 4 |
| Input Leakage | IIL | -3 |  | 3 | μA | VIN = 0V to VCC | 4 |
| Output Leakage | IOL | -3 |  | 3 | μA | VIN = 0V to VCC, TAC = 0°C to 70°C | 4 |
| Input Low-voltage | VIL | -0.6 |  |  | V |  | 4 |
| Output Low-voltage (3.6V ≤ VCC ≤ 5.5V) | VOL1 |  |  | 0.4 | V | 3.6V ≤ VCC ≤ 5.5V, IOL = 3.0mA | 4 |
| Output Low-voltage (1.8V ≤ VCC ≤ 3.6V) | VOL2 |  |  | 0.2 | V | 1.8V ≤ VCC ≤ 3.6V, IOL = 0.15mA | 4 |
| Output Capacitance (SO) | COUT |  |  | 8 | pF | VOUT = 0V; TA = 25C, f = 1.0MHz, VCC = 5.0V | 4 |
| Input Capacitance (CS, SCK, SI, WP, HOLD) | CIN |  |  | 6 | pF | VIN = 0V; TA = 25C, f = 1.0MHz, VCC = 5.0V | 4 |
| SCK Clock Frequency | fSCK | 0 |  | 5 | MHz | VCC = 1.8V to 5.5V | 5 |
| Input Rise Time | tRI |  |  | 2 | μs | VCC = 1.8V to 5.5V | 5 |
| Input Fall Time | tFI |  |  | 2 | μs | VCC = 1.8V to 5.5V | 5 |
| SCK High Time | tWH | 80 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| SCK Low Time | tWL | 80 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| CS High Time | tCS | 100 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| CS Setup Time | tCSS | 100 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| CS Hold Time | tCSH | 100 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| Data In Setup Time | tSU | 20 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| Data In Hold Time | tH | 20 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| HOLD Setup Time | tHD | 20 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| HOLD Hold Time | tCD | 20 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| Output Valid | tV |  |  | 80 | ns | VCC = 1.8V to 5.5V | 5 |
| Output Hold Time | tHO | 0 |  |  | ns | VCC = 1.8V to 5.5V | 5 |
| HOLD to Output Low Z | tLZ | 0 |  | 100 | ns | VCC = 1.8V to 5.5V | 6 |
| HOLD to Output High Z | tHZ |  |  | 200 | ns | VCC = 1.8V to 5.5V | 6 |
| Output Disable Time | tDIS |  |  | 200 | ns | VCC = 1.8V to 5.5V | 6 |
| Write Cycle Time | tWC |  |  | 5 | ms | VCC = 1.8V to 5.5V | 6 |
| Operating Temperature |  | -55 |  | 125 | C |  | 2 |
| Storage Temperature |  | -65 |  | 150 | C |  | 2 |
| Voltage on Any Pin with Respect to Ground |  | -1 |  | 7 | V |  | 2 |
| Maximum Operating Voltage |  |  |  | 6.25 | V |  | 2 |
| DC Output Current |  |  |  | 5 | mA |  | 2 |
| Recommended Operating Temperature (Industrial) | TAI | -40 |  | 85 | °C | VCC = 1.8V to 5.5V | 4 |

## Materials and finish

As the datasheet states them (page.json `metadata.appearance`; the 3D model's colours follow it).

| Part | Material | Colour / plating | Datasheet says | Page |
|---|---|---|---|---|
| contacts |  | tin | U = Green, Matte Sn Lead Finish | 14 |

## CAD (KiCad official)

- Symbol: `AT25640B-XHL-B`
- Footprint: `Package_SO:TSSOP-8_4.4x3mm_P0.65mm`
- 3D model: TSSOP-8 (KiCad packages3D, STEP)
- 3D model files: `at25640b-xhl-b-etched.step` / `at25640b-xhl-b-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `at25640b-xhl-b.step` / `at25640b-xhl-b.glb` are the bare package body.

## Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

- **Datasheet:** [Microchip Tech datasheet](docs/at25640b-xhl-b-datasheet.pdf) (23 pp, sha256 `6eb63f39b2e61b60`, retrieved 2026-11-06, tier: manufacturer)
- **Extractor:** parts-factory `2.0.0` / `extract_pins 0.3`, primary `claude-haiku-5-5` (text), consensus `claude-sonnet-5-5` (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
- **CAD:** KiCad official libraries (CC-BY-SA 4.0).

[Datasheet PDF](docs/at25640b-xhl-b-datasheet.pdf)