# ETA9740E8A

**etasolution** · Battery Management · ESOP8

ETA9740E8A from etasolution, in a ESOP8. 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 | SW | output | Inductor connection: connect an inductor between SW and the regulator output. |
| 2 | LED1 | output | Fuel gauge LED1 and LED2 connection pin. |
| 3 | LED2 | output | Fuel gauge LED3 and LED4 connection pin (as printed; the name LED2 and the description do not match, see review notes). |
| 4 | LED3 | output | Fuel gauge LED1, LED2, LED3 and LED4 connection pin (as printed in the datasheet). |
| 5 | ISET | passive | Buck charging current setting pin: connect a resistor between this pin and analog ground to set the charge current level. |
| 6 | BAT | bidirectional | Battery pin: connect the Li-ion battery here and place a 10uF bypass capacitor with it. |
| 7 | OUT | bidirectional | Output pin: bypass with a 22uF or larger ceramic capacitor placed close between this pin and GND. |
| 8 | PGND | power_in | Power ground pin. |
| 9 | AGND | power_in | Analog ground pin, also the exposed pad of the ESOP-8 package. |

## Key specifications

| Parameter | Value |
|---|---|
| Manufacturer | etasolution |
| Package | ESOP8 |
| Category | Power Management (PMIC) |
| Pins | 9 |

## Electrical characteristics

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

| Parameter | Symbol | Min | Typ | Max | Unit | Conditions | Page |
|---|---|---|---|---|---|---|---|
| USB Range |  | 4.5 |  | 5.5 | V |  | 2 |
| Battery CV Voltage |  | 4.17 | 4.21 | 4.25 | V | IBAT =0mA, default | 2 |
| Output Voltage Range |  | 5.05 | 5.1 | 5.15 | V | Iout=0 | 2 |
| Switching Frequency |  | 550 | 650 | 750 | KHz | VIN<4.3V | 2 |
| Operating Temperature Range |  | -40 |  | 85 | °C |  | 2 |
| Storage Temperature Range |  | -55 |  | 150 | °C |  | 2 |
| ESD HBM (Human Body Model) |  |  |  | 2 | KV |  | 2 |
| ESD MM (Machine Model) |  |  |  | 200 | V |  | 2 |
| OUT, SW Voltage |  | -0.3 |  | 6 | V |  | 2 |
| All Other Pin Voltage |  | -0.3 |  | 6 | V |  | 2 |
| Thermal Resistance JA (ESOP8) | JA |  | 10 |  | °C/W |  | 2 |
| Thermal Resistance Jc (ESOP8) | Jc |  | 50 |  | °C/W |  | 2 |
| USB UVLO Voltage |  |  | 4.5 |  | V | Voltage Rising, Hys=500mV | 2 |
| USB Operating Current as BUCK |  |  | 5 |  | mA | Switcher Enable, Switching | 2 |
| USB Operating Current as BUCK |  |  | 800 |  | μA | Switcher Enable, No Switching | 2 |
| Charger Restart Threshold From DONE to Fast Charge |  |  | -160 |  | mV |  | 2 |
| Battery Pre-Condition Voltage |  |  | 2.8 |  | V | VBAT Rising Hys=250mV | 2 |
| Pre-Condition Charge Current |  |  | 200 |  | mA |  | 2 |
| Fast Charge Current |  |  | 3 |  | A | Riset=56K | 2 |
| Fast Charge Current |  |  | 2 |  | A | Riset=91K | 2 |
| Charge Termination Current |  |  | 200 |  | mA |  | 2 |
| Charge Termination Blanking time |  |  | 16 |  | S |  | 2 |
| BATT Ok Threshold |  |  | 3.2 |  | V | Rising, HYS=0.4V | 2 |
| Quiescent Current |  |  | 80 |  | μA | At BATT Vbat=3.6V | 2 |
| Inductor Peak Current Limit |  |  | 5 |  | A |  | 2 |
| Maximum Duty Cycle |  |  | 90 |  | % |  | 2 |
| Highside Pmos Rdson |  |  | 75 |  | mΩ | ISW =500mA | 2 |
| Low side Nmos Rdson |  |  | 70 |  | mΩ | ISW =500mA | 3 |
| Short Circuit Hiccup Current |  |  | 3.8 |  | A |  | 3 |
| Short Circuit Hiccup Timer On Time |  |  | 45 |  | ms |  | 3 |
| Short Circuit Hiccup Timer Off Time |  |  | 2000 |  | ms |  | 3 |
| Charging Thermal Regulation threshold |  |  | 85 |  | °C |  | 3 |
| Thermal Shutdown |  |  | 150 |  | °C | Rising, Hys=20°C | 3 |

## CAD (KiCad official)

- Symbol: `ETA9740E8A`
- Footprint: `Package_SO:SOIC-8-1EP_3.9x4.9mm_P1.27mm_EP2.29x3mm`
- 3D model: ESOP8 (KiCad packages3D, STEP)
- 3D model files: `eta9740e8a-etched.step` / `eta9740e8a-etched.glb` carry the MPN laser-etched on the die in a toggleable `Adom.LaserEtch` group (Fusion-ready); `eta9740e8a.step` / `eta9740e8a.glb` are the bare package body.

## Provenance

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

- **Datasheet:** [etasolution datasheet](https://jlcpcb.com/api/file/downloadByFileSystemAccessId/8590905163924389888) (5 pp, sha256 `ae4c4d10be8f1025`, retrieved 2026-10-18, tier: lcsc)
- **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/eta9740e8a-datasheet.pdf)