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In my current design, just for uniformity I wish to keep all the components as SMD. There is one copper line on the PCB which goes up to 1000V (with current in milliamps obviously,) for which I need to attach a resistor and capacitor across it.
Most of the components I found which bear 1kV voltage are through hole. Are there any SMD components that I can use?
There is the Bourns CHV series of high voltage resistors. The CHV2010 model can stand up to 2 kV and CHV2512 up to 3 kV continuous.
However, clearance and creepage requirements are often larger. For example, IEC 61010 specifies 5.0 mm creepage distance for 1 kV secondary circuits in normal indoor conditions. But that CHV2010 resistor only has 3.7 mm distance between its terminals. Thus it would require potting to actually pass the requirements of that standard.
As other answers have mentioned, putting multiple resistors and capacitors in series is often a better alternative. But when doing that, do also pay attention to the required insulation distances.
Is there any SMD component that I can use?
You have to employ tricks when you have 1 kV around like putting a bunch of lower voltage rated resistors in series (as per the light blue block below): -
Notice also the cut-out in the PCB directly below R104-106 - this allows you to get components a little closer. For capacitors (purple box) - these are 2 kV rated devices and have a cut-out on the PCB to to give a little more clearance and voltage withstand. Surface mount capacitors are commonly available over 1 kV rating.
There are some large case (e.g. 1206, 1210, 1812, 2512) capacitors in pF and nF range having at least 1kV rated voltage.
For resistors, things are a bit different. For example, today's 1206 case resistors do not withstand voltages higher than 200-300V (acc. to datasheets at least). So you need to put multiple resistors connected in series in any case taking the power dissipations and clearances into account as well.
You do place them in a series string, for example five of them. Also keep in mind that miliamperes on kV range is high power and dangerous.
HI Res photo - Courtesy of EEVblog
