RockBLOCK Power Supply and On/Off Control
Overview
RockBLOCK modules require a stable DC power supply and careful management of the On/Off control to ensure reliable operation. This document provides detailed guidance on power requirements, current limits, alternative power sources, and safe microcontroller interfacing.
Power Supply Requirements
RockBLOCK modules include a voltage regulation circuit with a supercapacitor to meet the short, high-current demands of the internal Iridium module during transmission. This design simplifies power requirements for the host system.
When power is first applied, the supercapacitor charges, delaying Iridium module activation by approximately 10 seconds. However, RockBLOCK can be switched off while maintaining charge, allowing for an immediate restart (see On/Off Control).
DC Input Voltage and Current Limits
The host system must provide regulated DC power. The table below shows the required voltage and current ranges:
| Model | Minimum (V) | Maximum (V) | Maximum Current (mA) |
|---|---|---|---|
| RockBLOCK 9603 (5V input) | 3.0 | 5.4 | 470 |
| RockBLOCK 9603 (3.7V input) | 3.5 | 5.4 | 470 |
| RockBLOCK 9602 (5V input, with capacitors) | 4.5 | 5.4 | 470 |
| RockBLOCK 9602 (5V input, capacitors removed) | 4.5 | 5.4 | 1.5A peak required |
| RockBLOCK Plus | 9.0 | 30.0 | 225 |
🚧 RockBLOCK 9603 (Rev F) Power & Current Limit
- RockBLOCK 9603 Rev F has a fixed current limit of ~500mA, whether powered via 5V or Li-ion input.
- The minimum supply capability must be 500mA. A lower current source will cause brownouts during transmission.
- DO NOT remove the supercapacitors from the RockBLOCK 9603! They are essential for proper operation.
Removing supercapacitors will cause the module to malfunction and may permanently damage it.
Alternative Power Supply
RockBLOCK supports alternative power sources, including Li-ion batteries, but certain conditions must be met.
RockBLOCK 9602 - Power Considerations
RockBLOCK 9602 (with supercapacitors)
- Requires 4.5V – 5.4V input.
- Peak current demand is handled internally by supercapacitors.
- Supply current rating: 470mA maximum.
RockBLOCK 9602 (with supercapacitors removed)
- Supercapacitor removal is not recommended unless absolutely necessary.
- Peak transmission current increases significantly to 1.5A @ 5V (~10ms bursts).
- Power supply must be capable of delivering 1.5A reliably to prevent brownouts.
RockBLOCK 9603 - Power Considerations
| Model | Li-Ion Input Voltage (V) | Notes |
|---|---|---|
| RockBLOCK 9603 | 3.0V – 5.4V | Always current-limited to 500mA |
🚧 RockBLOCK 9603 Li-Ion Input & Schottky Diode
- The 9603 includes a Schottky diode (D1) between the Li-Ion (Pin 9) and 5V rail (Pin 8).
- This prevents backfeeding voltage into a 3.7V battery if 5V is applied to the main supply.
- If only using a low voltage power source (e.g., 3.7V Li-Ion), connect directly to Pin 8 (5V rail).
🚧 Supercapacitor Warning
- RockBLOCK 9603 limits current to 500mA, so removing supercapacitors serves no purpose.
- DO NOT remove the supercapacitors from RockBLOCK 9603! This will cause it to fail.
🚧 Li-Ion Power Considerations
- Do not exceed 5.4V, as this may overcharge the supercapacitor.
- If using Li-Ion power, do NOT connect 5V power to any other pin.
- If using an FTDI cable, cut the red USB power wire.
On/Off Control
Voltage Requirements (On/Off Pin)
| Model | Off (V) | On (V) | Notes |
|---|---|---|---|
| RockBLOCK 9602/9603 (pre-v3.F) | < 2.0 | > 2.4 | Standard logic |
| RockBLOCK 9603 (Rev F) | Supply - 1.5V | Supply - 0.5V or floating | No leakage current allowed |
| RockBLOCK Plus | < -1.5 | > 1.5 | 30V tolerance |
🚧 RockBLOCK 9603 (Rev F) On/Off Control
- OFF = Supply voltage - 1.5V (e.g., if supply = 5V, OFF ≤ 3.5V).
- ON = Supply voltage - 0.5V or floating (e.g., if supply = 5V, ON ≥ 4.5V).
- More than 1µA leakage on the On/Off pin can power down the module.
Microcontroller Interfacing (Only for RockBLOCK 9603 Rev F)
⚠️ This section applies ONLY to RockBLOCK 9603 Rev F (3.F) and its On/Off control.
Earlier versions and other RockBLOCK models are not affected by these requirements.
✔ Microcontroller must drive the On/Off pin at the same voltage as the RockBLOCK supply.
✔ If using a 3.3V MCU with a 5V RockBLOCK 9603 Rev F, ensure the MCU is 5V-tolerant OR use level shifting.
✔ More than 1µA leakage from the MCU into the On/Off pin can cause RockBLOCK 9603 Rev F to turn off.