HTSSOP-16 is a 16-lead, 0.65 mm-pitch TSSOP body with an exposed thermal pad on the underside, built to Texas Instruments’ PWP0016A outline. It’s the standard package for mid-power buck controllers and regulators, but one detail catches engineers who assume the pad is an automatic ground path: on several TI parts, it explicitly is not.
Key takeaways
- TI’s 16-pin PowerPAD outline is drawing PWP0016A (mechanical drawing 4214868/A, revised 02/2017), rated to 1.2 mm max package height, referencing JEDEC MO-153.
- Lead pitch is 0.65 mm across 16 leads (8 per side), each 0.30/0.19 mm wide; body dimensions are 5.1/4.9 mm × 4.5/4.3 mm — independently confirmed as 5 mm × 4.4 mm on TI’s LM53602-Q1 product page.
- The exposed pad is not automatically a ground connection: TI states outright for the TPS4007x family that the PowerPAD itself cannot be used as the device ground connection — the two device grounds must be connected as well.
- Real 16-pin PowerPAD thermal data (LM53602/LM53603): RθJA 42.5°C/W, RθJC(top) 22.6°C/W, RθJB 16.2°C/W, ψJT 0.6°C/W, ψJB 16.0°C/W, RθJC(bottom) 1.1°C/W.
- Solder stencil aperture for the pad scales with stencil thickness: four TI-published combinations from 0.175 mm stencil / 2.79×2.79 mm opening down to 0.1 mm stencil / 3.69×3.69 mm opening.
- Real 16-HTSSOP buck regulators run $4.73 single-unit down to $2.69 at 1,000 pieces (LM43602PWPR, DigiKey) — and older 16-pin HTSSOP parts do go end-of-life (TPS40061PWP is unavailable at RS Components).
Land pattern and mechanical dimensions
TI’s PWP0016A drawing (4214868/A, 02/2017) defines a 16-lead, 0.65 mm-pitch package with lead width 0.30 mm max / 0.19 mm min, package height capped at 1.2 mm, and references JEDEC registration MO-153. The body envelope runs 5.1/4.9 mm by 4.5/4.3 mm.
| Parameter | Value | Source |
| Lead count / pitch | 16 leads, 0.65 mm pitch (8 per side) | TI PWP0016A drawing 4214868/A |
| Lead width | 0.30 mm max / 0.19 mm min | TI PWP0016A drawing 4214868/A |
| Max package height | 1.2 mm | TI PWP0016A drawing 4214868/A |
| Body dimensions (A × B) | 5.1/4.9 mm × 4.5/4.3 mm | TI PWP0016A drawing 4214868/A |
| Body dimensions (independent check) | 5 mm × 4.4 mm × 1 mm | TI LM53602-Q1 product page |
| Base JEDEC family | MO-153 (TSSOP outline family) | TI PWP0016A drawing 4214868/A |
Two independent TI sources — the raw package drawing and a device product page — agree on the same 5 × 4.4 mm body footprint, which is a stronger confirmation than relying on either alone.
Stencil design by thickness
TI publishes four stencil-thickness/aperture pairs for the PWP0016A thermal pad: 0.175 mm stencil with a 2.79×2.79 mm opening, 0.15 mm stencil with a 3.01×3.01 mm opening, the 0.125 mm reference design at 3.3×3.3 mm, and 0.1 mm stencil with a 3.69×3.69 mm opening.
| Stencil thickness | Solder stencil opening |
| 0.175 mm | 2.79 × 2.79 mm |
| 0.15 mm | 3.01 × 3.01 mm |
| 0.125 mm (reference design) | 3.3 × 3.3 mm |
| 0.1 mm | 3.69 × 3.69 mm |
TI notes laser-cut apertures with trapezoidal walls and rounded corners may offer better paste release, and points to IPC-7525 for alternate stencil design recommendations — worth checking against your board house’s own capability before finalizing gerbers. The general PowerPAD via rules still apply here: 0.33 mm (13 mil) via diameter or smaller, five to nine vias for a small die, minimum 50% solder coverage of the pad area.
Thermal performance: a real 16-pin device
TI’s LM53602/LM53603 automotive buck converters, in the 16-pin PWP (HTSSOP) package, publish a complete thermal table: RθJA of 42.5°C/W, RθJC(top) of 22.6°C/W, RθJB of 16.2°C/W, ψJT of 0.6°C/W, ψJB of 16.0°C/W, and RθJC(bottom) of 1.1°C/W.
| Thermal metric | Value |
| RθJA (junction-to-ambient) | 42.5 °C/W |
| RθJC(top) (junction-to-case, top) | 22.6 °C/W |
| RθJB (junction-to-board) | 16.2 °C/W |
| ψJT (junction-to-top characterization) | 0.6 °C/W |
| ψJB (junction-to-board characterization) | 16.0 °C/W |
| RθJC(bottom) (junction-to-case, bottom/pad) | 1.1 °C/W |
The gap between RθJC(top) at 22.6°C/W and RθJC(bottom) at 1.1°C/W shows exactly why the pad matters: heat leaving through the soldered pad meets roughly 20x less resistance than heat leaving through the top of the molded body.
The ground-connection mistake
Don’t assume the exposed pad grounds the device just because it’s soldered to a copper plane. TI states plainly for the TPS4007x family: “due to the die attach method, the PowerPAD itself cannot be used as the device ground connection. The two device grounds must be connected as well.” The pad removes heat; it does not substitute for wiring the actual GND pin.
Other 16-pin HTSSOP parts handle it differently, which is exactly why this needs checking per device rather than assumed from the package: TI’s TPS4005x family requires the PowerPAD heat slug to be connected to SGND (pin 5) or left electrically isolated from all other pins — a binary choice, not automatic. Treat the pad’s electrical function as a per-datasheet lookup every time, not a package-level constant.
TSSOP-16 vs. HTSSOP-16
| Attribute | TSSOP-16 | HTSSOP-16 (PWP0016A) |
| Lead pitch | 0.65 mm | 0.65 mm (same) |
| Lead count | 16 | 16 (same) |
| Exposed thermal pad | No | Yes, underside |
| Body dimensions | ~4.4 mm body width family | 5 × 4.4 mm (PWP0016A) |
| PCB attach for rated thermal performance | Leads only | Leads + soldered pad |
| Ground behavior | N/A | Varies by device — check the pin table |
| Typical use case | Low-power logic, general ICs | Buck controllers, regulators, motor drivers |
Use HTSSOP-16 when the standard package’s dissipation rating falls short of your worst-case load; plain TSSOP-16 saves the extra land-pattern and via work when it doesn’t.
Sourcing reality
TI’s LM43602PWPR, a 16-HTSSOP buck regulator, lists at $4.73 for a single unit on DigiKey, dropping to $3.597 at 10 pieces and $2.69088 at 1,000-piece pricing — a meaningful spread worth modeling into a BOM before committing to volume. Older 16-pin HTSSOP parts do reach end of life: TI’s TPS40061PWP, a 16-pin HTSSOP buck controller, shows as unavailable and no longer stocked at RS Components, a reminder to check part-status flags independent of the package itself.
Frequently asked questions
What is the land pattern for HTSSOP-16?
TI’s PWP0016A drawing (4214868/A) defines 16 leads at 0.65 mm pitch, 0.30/0.19 mm lead width, 1.2 mm max height, body dimensions of roughly 5×4.4 mm, referencing JEDEC MO-153.
What stencil thickness should I use for HTSSOP-16?
Four TI-published combinations: 0.175 mm stencil with a 2.79×2.79 mm aperture down to 0.1 mm stencil with a 3.69×3.69 mm aperture — choose based on your board house’s process capability.
Can the PowerPAD be used as the device ground connection?
Not automatically. TI states for the TPS4007x family that the PowerPAD cannot substitute for the device ground connection due to the die attach method — the actual ground pin must still be connected. Other devices, like the TPS4005x, require the pad tied to a specific SGND pin or left isolated. Always check the datasheet.
What’s the difference between TSSOP-16 and HTSSOP-16?
No difference in lead pitch or count — only the added exposed thermal pad on the HTSSOP-16 underside and the resulting PCB land, via, and (device-dependent) ground requirements.
What is the thermal resistance of a 16-pin HTSSOP part?
Varies by device; TI’s LM53602/LM53603 publishes RθJA of 42.5°C/W on a JEDEC-standard board — always use the specific part’s datasheet number, not a generic package estimate.
The decision
Specify HTSSOP-16 (PWP0016A) when your regulator or controller’s standard-package thermal derating can’t clear your worst-case dissipation. Pull the stencil aperture from the four TI-published thickness options, size vias to 0.33 mm or smaller, and — before you route the ground net — confirm in the specific datasheet whether the pad grounds the device automatically or needs a separate ground connection alongside it. That single check is the difference between a working board and a respin.
[IMAGE 1: PWP0016A land pattern with dimensioned pad and lead pitch | alt: “HTSSOP-16 PWP0016A land pattern diagram”]
[IMAGE 2: Solder stencil aperture comparison at four stencil thicknesses | alt: “HTSSOP-16 stencil aperture by thickness table”]
[INTERNAL LINK: HTSSOP package overview and thermal design → HTSSOP package guide]
[INTERNAL LINK: HTSSOP-14 land pattern and thermal pad → HTSSOP-14 package guide]
[INTERNAL LINK: PCB thermal via design for exposed-pad packages → PCB layout guide]
