JSM4057 from JSMSEMI, in a SOT-23-6L. Pinout and pin descriptions extracted from the manufacturer datasheet by ds2sf; symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin	Name	Type	Function
1	CHRG	output	Open-drain charge status indicator. Pulled low by the internal switch while the battery is being charged; high-impedance otherwise. Typically drives a red LED to VCC through a series resistor. VOL ≈ 0.3 V @ 5 mA sink.
2	GND	power_in	Device ground / power return.
3	BAT	power_out	Battery positive terminal. Sources charge current to the cell and regulates to 4.2 V float voltage. In standby / no-VCC condition, BAT leakage current is <3 uA. Absolute max BAT current 600 mA; absolute max voltage -0.3 V to 7 V.
4	VCC	power_in	Input supply (USB or adapter). Operating range 4.0 V - 6 V (absolute max -0.3 V to 7 V). Charging begins when VCC is above the UVLO threshold (typ 3.7 V) AND at least 100 mV above BAT. A 2.2 uF decoupling capacitor to GND is recommended.
5	STDBY	output	Open-drain charge-complete indicator. Pulled low by the internal switch when the charge cycle has terminated; high-impedance during charging or fault. Typically drives a green LED. VOL ≈ 0.3 V @ 5 mA sink.
6	PROG	input	Constant-current programming pin. Connect a resistor RPROG from PROG to GND to set the fast-charge current: IBAT = 1000 V / RPROG (e.g. 2 kΩ → 500 mA). PROG is regulated to 1.0 V in constant-current mode and 0.1 V in trickle mode; termination occurs when the servo voltage falls below 100 mV for >2 ms. Absolute max PROG voltage -0.3 V to 0.3 V; max current 600 uA.

Key specifications

Parameter	Value
Manufacturer	JSMSEMI
Package	SOT-23-6L
Category	PMIC
Pins	6

Ordering variants

Same part, different packaging or reel option.

JSM4057TP4057

CAD (KiCad official)

Symbol: JSM4057
Footprint: Package_TO_SOT_SMD:SOT-23-6
3D model: SOT-23-6L (KiCad packages3D, STEP)

3D model downloads

Two STEP files. Same geometry, different body top:

File	Size	Use it when
`jsm4057.step`	97 KB	You want the bare part, or you mark your own boards.
`jsm4057-etched.step`	1.5 MB	You want the part with `JSM4057` already on it.

The marking in the etched file is real recessed geometry cut into the solid, not a texture or a decal: 372 faces against 117 in the bare model. It survives export, section views, and rendering in any CAD tool, and it drops straight into KiCad or Fusion with no extra setup.

Provenance

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

Datasheet: JSMSEMI datasheet (6 pp, sha256 a94e1f5c3680b72e, retrieved 2026-08-17, tier: lcsc)
Datasheet language: Chinese. Pin names, descriptions, and specs on this page were extracted and translated to English by ds2sf; the linked PDF is the manufacturer original.
Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF