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Contents

README

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TPS51123RGER

Texas Instruments · AC-DC Controllers and Regulators · VQFN-24-EP(4x4)

TPS51123RGER from Texas Instruments, in a VQFN-24-EP(4x4). 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 TRIP1 bidirectional Channel 1 OCL trip setting pin. Connect a resistor from this pin to GND to set the overcurrent threshold for the synchronous RDS(on) current sense (ITRIP typ 10 μA, 4500 ppm/°C).
2 VFB1 input Channel 1 SMPS feedback input. Connect to the output via a feedback resistor divider; regulates to the 2-V internal reference.
3 VREF output 2-V (±1%) internal reference voltage output. Bypass with a 220-nF to 1-μF ceramic capacitor to signal GND close to the device.
4 TONSEL input On-time / switching-frequency selection pin. Tie to VREG5 (365/460 kHz), VREG3 (300/375 kHz), VREF (245/305 kHz), or GND (200/250 kHz).
5 VFB2 input Channel 2 SMPS feedback input. Connect to the output via a feedback resistor divider; regulates to the 2-V internal reference.
6 TRIP2 bidirectional Channel 2 OCL trip setting pin. Connect a resistor from this pin to GND to set the overcurrent threshold for the synchronous RDS(on) current sense.
7 VO2 bidirectional Channel 2 output-voltage connection to the SMPS. Acts as a fixed voltage input and output-discharge sink, and also as the 3.3-V switch-over return power input for the VREG3 LDO.
8 VREG3 power_out 3.3-V, 100-mA internal LDO output. Bypass with a 1-μF (unloaded) or 10-μF ceramic capacitor to power GND near the device.
9 VBST2 power_in Channel 2 high-side N-channel MOSFET driver bootstrap supply. Connect a bootstrap capacitor (typ 0.1 μF) between VBST2 and LL2; internal boot diode charges from VREG5.
10 DRVH2 output Channel 2 high-side N-channel MOSFET gate driver output. Referenced to LL2. Rsource ≈ 4 Ω, Rsink ≈ 1.5 Ω.
11 LL2 input Channel 2 switch-node sense input. Provides high-side driver return, current-limit sensing, and control-loop timing reference.
12 DRVL2 output Channel 2 low-side N-channel MOSFET gate driver output. Referenced to GND, supplied from VREG5. Rsource ≈ 4 Ω, Rsink ≈ 1.5 Ω.
13 EN0 bidirectional Master enable input. Open (2.4-V enable threshold) turns the LDOs on and readies both switcher channels; tie to GND to disable the entire device.
14 SKIPSEL input Operation-mode select pin. Tie to VREG3/VREG5 for OOA auto-skip, to VREF for PWM-only, or to GND for standard auto-skip light-load operation.
15 GND power_in Device ground. The QFN PowerPAD on the underside should also be soldered to the GND plane with 3×3 thermal vias for the specified 1.85 W dissipation rating.
16 VIN power_in High-voltage power supply input for the 5-V and 3.3-V LDOs. Recommended operating range 5.5 V to 28 V (abs max 30 V).
17 VREG5 power_out 5-V, 100-mA internal LDO output; also supplies the low-side gate drivers and boot-diode source. Bypass with a 33-μF ceramic capacitor to power GND near the device.
18 ENC input Channel 1 and Channel 2 SMPS enable input. Pull up to 3.3-5 V to enable both switcher channels; short to GND to shut both channels down (enable threshold 2 V, shutdown ≤ 0.6 V).
19 DRVL1 output Channel 1 low-side N-channel MOSFET gate driver output. Referenced to GND, supplied from VREG5. Rsource ≈ 4 Ω, Rsink ≈ 1.5 Ω.
20 LL1 input Channel 1 switch-node sense input. Provides high-side driver return, current-limit sensing, and control-loop timing reference.
21 DRVH1 output Channel 1 high-side N-channel MOSFET gate driver output. Referenced to LL1. Rsource ≈ 4 Ω, Rsink ≈ 1.5 Ω.
22 VBST1 power_in Channel 1 high-side N-channel MOSFET driver bootstrap supply. Connect a bootstrap capacitor (typ 0.1 μF) between VBST1 and LL1; internal boot diode charges from VREG5.
23 PGOOD output Combined power-good open-drain output (logical AND of channel 1 and channel 2 power-good). Sink capability 5 mA min at 0.5 V; pull up externally.
24 VO1 bidirectional Channel 1 output-voltage connection to the SMPS. Acts as a fixed voltage input and output-discharge sink, and also as the 5-V switch-over return power input for the VREG5 LDO.
PAD PowerPAD power_in Exposed thermal pad on the underside of the QFN. Must be soldered to the GND plane (recommended 3×3 thermal via array) for the rated 1.85 W dissipation.

Key specifications

Parameter Value
Manufacturer Texas Instruments
Package VQFN-24-EP(4x4)
Category PMIC
Pins 25

Ordering variants

Same part, different packaging or reel option.

  • TPS51123RGER
  • TPS51123RGERRGET

CAD (KiCad official)

  • Symbol: TPS51123RGER
  • Footprint: Package_DFN_QFN:QFN-24-1EP_4x4mm_P0.5mm_EP2.7x2.7mm
  • 3D model: VQFN-24-EP(4x4) (KiCad packages3D, STEP)

Provenance

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

  • Datasheet: Texas Instruments datasheet (38 pp, sha256 c26be1d356b1d431, retrieved 2026-08-17, tier: lcsc)
  • 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