DS200PCCAG5ACB | 40MHz Conformal Coated

Description

Product Introduction

The DS200PCCAG5ACB combines the G5A’s performance and brownout protection with moisture resistance. The standard G5A runs fine in a clean control room. Put it in a paper mill or a coastal cabinet, and the humidity eventually kills it. This board keeps running.

The “CB” suffix adds a single coat of acrylic conformal coating (25µm) to the G5A hardware. Same 40MHz 68EC040, same 4MB interleaved RAM, same 8MB AMD flash with brownout detector. The coating protects the PCB and component leads from condensation, but leaves the processor socket and backplane connector exposed. To be blunt, the G5A’s Achilles’ heel is the 160-pin QFP processor package—the leads are only 0.5mm apart, and moisture creates conductive bridges. The CB coating covers the PCB around the processor but not the chip itself. It’s not a full seal, but it reduces leakage current by about 90% in high-humidity conditions.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement: DS200PCCAG5A
Standard version without conformal coating. Same pinout. Swaps directly. Use in dry, climate-controlled environments only.

✅ Drop-in Replacement: DS200PCCAG5ABB
Full environmental version (triple coat, wide-temp -20°C to 60°C). Same pinout. Better for condensing environments or cold cabinets. Price is about 40% higher than CB.

⚠️ Software Compatible: DS200PCCAG6CB
Later generation (40MHz, 8MB RAM, ECC) with conformal coating. Same pinout. Requires no program changes for most applications. The G6 adds ECC RAM—your program doesn’t need to know.

❌ Hardware Incompatible: DS200PCCAG5 (no suffix)
Original G5 without brownout detector. Same pinout but lacks power-fault protection. Swaps directly but less reliable in dirty power environments.

Frequently Asked Questions (FAQ)

How do I inspect the coating around the 160-pin QFP processor?
That’s the critical area. Use a 20x loupe or a USB microscope. Look at the four sides of the processor (U1, the large square chip). The coating should cover the PCB up to the edge of the chip’s body. It should not extend onto the chip itself or onto the exposed leads. If you see coating on the leads, it can insulate them and cause intermittent connections. If you see bare PCB between the leads and the chip, the coating is insufficient. Touch up with acrylic coating (MG Chemicals 422B) using a 00 brush.

My CB board works fine at 50% humidity but crashes at 80%. What’s wrong?
The coating is intact, but the processor socket (the chip is soldered directly—no socket on the G5A) isn’t the issue. The problem is likely the backplane connector. The CB coating doesn’t cover the connector pins. At high humidity, moisture forms between pins 4C and 4D (5V and ground) on the backplane, creating a momentary short. Clean the backplane connector with contact cleaner (DeoxIT D5). Apply dielectric grease to the connector pins (Dow Corning DC4). We’ve fixed six boards with this symptom.

What’s the typical failure mode on the CB board?
The coating outgasses at high temperature. The G5A’s processor runs at about 60°C under full load. The acrylic coating releases volatile compounds that condense on cooler surfaces—like the backplane connector pins. Over time (about 3-4 years), a film builds up on the pins, increasing contact resistance. Symptoms: intermittent backplane errors, especially on hot days. Clean the backplane connector with isopropyl alcohol. If the problem recurs within six months, the coating needs to be stripped and reapplied with a low-outgassing formulation. We offer this service for $200.

Can I run a CB board in a cabinet that sees frequent condensation?
Not reliably. The CB coating is designed for non-condensing environments (95% RH but no liquid water). In condensing conditions (air temperature drops below dew point), water droplets form on the board. The coating protects the PCB, but water can still bridge the exposed pins of the backplane connector, debug port header, and LED leads. If your cabinet condenses, buy the ABB version (triple coat) or add a cabinet heater to keep the temperature above the dew point. A 50 heater is cheaper than a 1,500 board.

How do I test the CB board’s humidity resistance without a chamber?
The salt spray shortcut (not MIL-STD but useful):

1. Mix 3% salt solution (30g salt per 970ml water).
2. Apply to the board with a fine mist sprayer. Focus on the area around the processor.
3. Let sit for 2 hours at 40°C (use a warm cabinet or a seedling heat mat).
4. Inspect under 20x magnification. Look for white residue between the processor leads.
   Genuine CB boards show no residue. Standard G5A boards show salt crystals bridging leads. If your CB board shows residue, the coating has pinholes. Touch up or return the board.

What’s the lead time for a DS200PCCAG5ACB from surplus stock?
1-3 weeks. The CB variant is moderately common—about 25% of G5A boards shipped with conformal coating. We maintain about 50 units in stock. Price is typically 15-20% higher than the standard G5A.

Do you offer a coating service for standard G5A boards?
Yes. Send us your standard G5A board. We clean it, mask the backplane connector and debug header, apply two coats of acrylic (50µm total), cure for 24 hours, and run a 24-hour humidity test (85% RH, 40°C). Cost is $175 per board. Turnaround is 5 business days. We also add a conformal coating to the bottom of the board (the original CB only coats the top). Pass rate is about 95%. We do not coat boards with existing corrosion or damaged components. The result exceeds the original CB specification (double the coating thickness, both sides). We’ll certify it as “CB-equivalent” for your maintenance records.

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