# DeepGrid D100 Drone SoC Multi-Die SiP Architecture Specification

**System**: DeepGrid D100 Tactical UAV Brain (Heterogeneous Multi-Die System-in-Package)  
**Classification**: Unclassified / Commercial & Defence Dual-Use Reference Architecture  
**Author**: DeepGrid Semi Pvt Ltd · Hyderabad, India  
**Process Technology**: 130nm CMOS (SkyWater 130 / IHP SG13G2) + BCD 180nm + 28nm Compute  
**Target Standards**: MIL-STD-810H, MIL-STD-461G, DGCA Type Certification, DAP-2020 Make-II  
**Generated Via**: `/architecture-to-everything` compounded with `/deepgrid-mature-silicon`

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## 1. Executive Summary & Sovereign Defense Thesis

### 1.1 The $9B Mature-Node Import Vulnerability
India's aerospace and commercial robotics sectors currently import over 95% of tactical UAV flight controllers, ESC power stages, and navigation silicon—principally from STMicroelectronics (STM32 series), Texas Instruments, Analog Devices, and Chinese commercial autopilot suppliers. Under active Electronic Warfare (EW) conditions along contested borders (LoC and LAC), foreign commercial microcontrollers suffer from:
1. **Unverifiable Firmware & Supply Chain Kill-Switches**: Foreign proprietary IP blocks cannot be formally verified against side-channel Trojan insertion.
2. **GPS-Denial Catastrophic Drift**: Commercial flight stacks depend entirely on GNSS satellite signals. Under front-line jamming, positioning rapidly diverges, triggering unrecoverable airframe loss.
3. **Firmware Watchdog Lockup**: Software-managed task schedulers (e.g., in RTOS or Linux) can deadlock during RF desensitization or high-power thermal throttling, locking motor PWM channels in indeterminate states.

### 1.2 The DeepGrid D100 Architectural Solution
The **DeepGrid D100** is an integrated System-in-Package (SiP) specifically engineered to replace fragmented, imported multi-board avionics stacks with a single, sovereign 15x15 mm BGA package. It combines:
- **Dual DGridRiscV Flight Cores (RV32IM_Safety)** running deterministic, hard real-time PX4 / ArduPilot loops at 200 MHz fixed clock.
- **Hardware 6-DoF Extended Kalman Filter (EKF) VIO Engine** processing MIPI CSI-2 optical streams and IMU telemetry at 30 Hz with $<1\%$ drift per kilometer under zero-GNSS conditions.
- **Dedicated, 100% Isolated Hardware Failsafe Island**: Pure digital RTL state machine with isolated power and clock domains that bypasses the main processors and directly drives motor ESCs into a controlled recovery descent upon command link loss.
- **Heterogeneous Organic SiP Integration**: 6 wire-bonded mature-node dies (PMIC, Supervisor, Transceiver, Motor Driver, AFE) combined with high-speed compute on a 4-layer organic BGA substrate, **deliberately rejecting costly UCIe or silicon interposers**.

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## 2. Silicon Process Physics & Subsystem Die Allocation

DeepGrid strictly enforces the **130nm Physics Boundary**: mature silicon handles high-voltage power conditioning, rugged analog signal acquisition, and ultra-high frequency RF, while high-density digital nodes are sequestered to isolated compute dies.

| Subsystem / Die | Node & Foundry | Key Technology & Physics | Target Socket / Function |
|---|---|---|---|
| **Flight Control & VIO SoC** | 130 nm CMOS (SkyWater SKY130) | Open-PDK standard cells, 5-metal stack, 200 MHz fixed clock | Dual DGridRiscV + Hardware EKF + ISP |
| **RF mmWave Radar Front-End** | 130 nm BiCMOS (IHP SG13G2) | SiGe:C Heterojunction Bipolar ($f_T = 350\text{ GHz}$, $f_{\max} = 450\text{ GHz}$) | 77 GHz 4D MIMO Radar collision avoidance |
| **SKU-3 Hi-Rel PMIC** | 180 nm BCD (SCL Mohali / X-FAB) | 5V–120V raw input, Brokaw bandgap (12 ppm/°C), DICE FSM latch | Centralized package power distribution tree |
| **SKU-6 Voltage Supervisor** | 180 nm CMOS | Chopper-stabilized comparator, 8 µs deglitch, 1.2% threshold | Sub-microsecond brownout detection & Master RESETn |
| **SKU-5 Tactical Transceiver** | 130 nm Thick-Oxide HV | 5V LDMOS drivers, $\pm 15\text{ kV}$ HBM ESD protection | CAN-FD (5 Mbps) & RS-485 tactical airframe bus |
| **Mission AI Compute Die** | 28 nm CMOS (Flip-Chip) | High-density digital standard cells, 2 MB SRAM, INT8/INT4 MACs | 10-TOPS YOLOv8 target tracking & terrain classification |

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## 3. Detailed Subsystem Block Specifications

### 3.1 Dual DGridRiscV Flight Control Core (RV32IM_Safety)
- **Instruction Set Architecture**: RV32IM_Zicsr (Standard 32-bit RISC-V integer arithmetic + hardware integer multiplier/divider).
- **Pipeline Structure**: 2-stage fetch / 6-stage execute deterministic pipeline.
- **Cacheless Microarchitecture**: To eliminate non-deterministic cache-miss jitter, the core executes code exclusively out of a **512 KB Zero-Wait-State Tightly-Coupled SRAM with Single-Error Correction Double-Error Detection (SECDED ECC)**.
- **Safety Redundancy**: Dual cores run in lockstep with a 2-cycle staggered temporal skew to prevent common-mode electrical transient faults. A hardware comparator triggers `FAULTn` within $\le 2$ clock cycles upon mismatch.

### 3.2 30 Hz Hardware Geometric EKF VIO Engine
In modern counter-UAS electronic warfare, GPS signals are spoofed or completely suppressed. The D100 implements pure geometric localization in hardware:
- **Optical Ingestion**: 2-lane MIPI CSI-2 interface ingesting 1080p60 grayscale optical tracking frames.
- **Hardware Image Signal Processor (ISP)**: On-the-fly debayering, high-dynamic-range (HDR) tone curve mapping, and FAST corner detector extracting up to 500 optical keypoints per frame.
- **Extended Kalman Filter (EKF)**: Hardwired matrix math accelerator solving 6-DoF pose equations (3-axis velocity, 3-axis orientation, accelerometer bias, gyro bias) at 30 Hz.
- **Drift Rate**: Geometric relative drift is constrained to **$<0.8\%$ of distance traveled**, enabling autonomous return-to-base without GPS or magnetic compass.

### 3.3 The Hardware Failsafe Island (The Hardware Wedge)
Unlike commercial flight controllers where failsafe procedures are executed by software routines (vulnerable to kernel panics, stack overflow, or memory corruption), the D100 implements a **100% physically isolated Failsafe Island**:
1. **Isolated Power & Clock Domain**: Powered by an independent internal low-dropout regulator (LDO) and driven by an on-chip ring oscillator decoupled from external crystals.
2. **Autonomous Hardware Link Monitor**: Directly samples RF telemetry packets, SBUS/CRSF receiver signals, and GNSS lock status. If loss-of-link persists beyond a programmable threshold (e.g., 500 ms), the island asserts state override.
3. **Emergency Safe-State FSM**: A pure combinational/synchronous finite state machine that calculates a steady-state rotor speed profile based on last-known altitude barometry.
4. **Hardwired Actuator Multiplexer (MUX)**: Positioned at the silicon I/O pad boundary. When activated, it **completely disconnects the main processors, VIO engine, and AI stack**, driving predictable recovery PWM/DShot signals directly to the motor ESCs.

```
+-------------------------------------------------------------------------------+
| D100 SILICON I/O BOUNDARY                                                     |
|                                                                               |
| [Main Flight Processor] ---> (Normal PWM/DShot) ---+                          |
|                                                    |                          |
|                                             +------v-------+                  |
|                                             | HARDWARE MUX | ===> ESC MOTORS  |
|                                             +------^-------+                  |
|                                                    |                          |
| [FAILSAFE ISLAND] ---------> (Emergency Override)--+                          |
|   - Independent LDO & Ring Osc                                                |
|   - Hardware Link Loss Timer                                                  |
|   - Zero-Software Safe-State FSM                                              |
+-------------------------------------------------------------------------------+
```

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## 4. Multi-Die System-in-Package (SiP) Packaging Architecture

### 4.1 Why "Deliberately Not UCIe"
Advanced chiplet packaging standards such as UCIe, TSMC CoWoS, or Intel EMIB require sub-micron silicon interposers, micro-bumps ($<40\ \mu\text{m}$ pitch), and access to offshore advanced packaging foundries. For sovereign Indian defence systems, this re-introduces the exact geopolitical vulnerability being avoided.

DeepGrid packages the D100 using a **standard 4-layer organic laminate substrate (FR4/BT core)**:
- **Package Dimensions**: $15 \times 15\text{ mm}$ Ball Grid Array (BGA), 0.8 mm ball pitch, 324-ball count.
- **Die Interconnect**: Mature dies (PMIC, Supervisor, Transceiver) are standard aluminum/gold wire-bonded ($25\ \mu\text{m}$ wire). The high-density compute die is flip-chip attached using copper pillar bumps ($100\ \mu\text{m}$ pitch).
- **Communication Protocol**: Inter-die communication utilizes standardized on-substrate routing buses: high-speed SPI, differential UART, and dedicated reset/interrupt GPIO lines.
- **Cost Impact**: Reduces packaging NRE from $>\$1.5\text{M}$ (silicon interposer) to $<\$35,000$ (organic substrate tooling), with high yield across domestic ATMP facilities.

### 4.2 Power Delivery Network (PDN) & Thermal Enclosure
- **Input Battery Rail**: Direct connection to drone LiPo battery packs (5V–120V raw input via SKU-3 BCD PMIC).
- **On-Package Regulated Rails**:
  - $1.2\text{ V} \pm 25\text{ mV}$ (Digital Core Logic, 12A dynamic load step).
  - $1.8\text{ V}$ (MIPI CSI-2 & Sensor Analog Front-End).
  - $3.3\text{ V}$ (Tactical I/O, CAN-FD, RS-485).
- **Thermal Budget**: Total SiP dissipation is capped at **4.8 W nominal (7.2 W peak under full NPU inference)**. A thermal copper slug embedded in the top mold cap interfaces directly with the drone's carbon-fiber chassis, maintaining junction temperature below $+105^\circ\text{C}$ in $+55^\circ\text{C}$ ambient desert environments.

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## 5. Defense Procurement Moats & Manufacturing Sovereignty

### 5.1 Defense Acquisition Procedure (DAP-2020) Moat
Under India's **DAP-2020 Buy (Indian-IDDM)** category, military procurement requires minimum 50% Indigenous Content (IC). The D100 qualifies for 100% IDDM status:
- **IP Ownership**: DeepGrid owns the complete RTL, GDSII layout, and packaging design.
- **Sovereign Fabrication Path**: Initial prototype and pilot production executes on SkyWater 130nm and IHP SG13G2; production transfer targets **SCL Mohali 180nm CMOS/BCD lines** for fully sovereign domestic fabrication.
- **Positive Indigenisation Lists (PIL)**: Directly addresses military import ban lists covering unmanned aerial vehicle flight controllers, power management modules, and counter-drone avionics.

### 5.2 Qualification & Screening Matrix
1. **MIL-STD-810H**: Method 501.7 (High Temp $+85^\circ\text{C}$ operating), Method 502.7 (Low Temp $-40^\circ\text{C}$ operating), Method 514.8 (Vibration profile for propeller-induced structural resonance).
2. **MIL-STD-461G**: Radiated emissions (RE102) and conducted susceptibility (CS114/CS116) against EW microwave and high-power radio interference.
3. **DGCA Type Certification**: Compliant with Directorate General of Civil Aviation standard civil airworthiness regulations for commercial drone operation in India.

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## 6. Architecture Verification & Interface Checklist

- [x] **Sensor Interface**: 2-Lane MIPI CSI-2 @ 1.2 Gbps/lane + 4x SPI avionics ports.
- [x] **Flight Control**: Dual DGridRiscV cores in lockstep, 512 KB ECC SRAM.
- [x] **Navigation Engine**: 30 Hz hardware EKF VIO ($<1\%$ drift/km).
- [x] **Failsafe Wedge**: Hardwired bypass MUX + Independent LDO & Ring Oscillator.
- [x] **Organic Packaging**: 15x15 mm BGA, 4-layer substrate, wire-bond + flip-chip.
- [x] **Supply Chain**: Fully documented SkyWater $\rightarrow$ IHP $\rightarrow$ SCL Mohali migration.